Do the Pros of Brown Rice Outweigh the Cons of Arsenic?

Are there unique benefits to brown rice that would justify keeping it in our diet despite the arsenic content?

For years, warnings had been given about the arsenic levels in U.S. rice potentially increasing cancer risk, but it had never been put to the test until a study out of Harvard. The finding? “Long-term consumption of total rice, white rice or brown rice[,] was not associated with risk of developing cancer in US men and women.” This was heralded as good news. Indeed, no increased cancer risk found even among those eating five or more servings of rice per week. But, wait a second: Brown rice is a whole grain, a whole plant food. Shouldn’t brown rice be protective and not just neutral? I discuss this in my video Do the Pros of Brown Rice Outweigh the Cons of Arsenic?.

If you look at whole grains in general, there is “a significant inverse”—or protective—“association between total whole-grain intake and risk of mortality from total cancers,” that is, dying from cancer. My Daily Dozen recommendation of at least three servings of whole grains a day was associated with a 10 percent lower risk of dying from cancer, a 25 percent lower risk of dying from heart attacks or strokes, and a 17 percent lower risk of dying prematurely across the board, whereas rice consumption in general was not associated with mortality and was not found to be protective against heart disease or stroke. So, maybe this lack of protection means that the arsenic in rice is increasing disease risk, so much so that it’s cancelling out some of the benefits of whole-grain brown rice.

Consumer Reports suggested moderating one’s intake of even brown rice, but, given the arsenic problem, is there any reason we should go out of our way to retain any rice in our diet at all? With all of the other whole grain options out there, should we just skip the rice completely? Or, are there some unique benefits we can get from rice that would justify continuing to eat it, even though it has ten times more arsenic than other grains?

One study showed that “a brown rice based vegan diet” beat out the conventional Diabetes Association diet, even after adjusting for the extra belly fat lost by the subjects on the vegan diet, but that may have been due to the plant-based nature of their diet rather than just how brown rice-based it was.

Another study found a profound improvement in insulin levels after just five days eating brown rice compared to white rice, but was that just because the white rice made people worse? No, the brown rice improved things on its own, but the study was done with a South Indian population eating a lot of white rice to begin with, so this may have indeed been at least in part a substitution effect. And yet another study showed that instructing people to eat about a cup of brown rice a day “could significantly reduce weight, waist and hip circumference, BMI, Diastole blood pressure,” and inflammation—and not just because it was compared to white. However, a larger, longer study failed to see much more than a blood pressure benefit, which was almost as impressive in the white-rice group, so, overall, not too much to write home about.

Then, another study rolled around—probably the single most important study on the pro-rice sideshowing a significant improvement in artery function after eight weeks of eating about a daily cup of brown rice, but not white, as you can see at 3:18 in my video, and sometimes even acutely. If you give someone a meal with saturated fat and white rice, you can get a drop in artery function within an hour of consumption if you have some obesity-related metabolic derangements. But, if you give brown rice instead of white, artery function appears protected against the adverse effects of the meal. Okay, so brown rice does show benefits in interventional studies, but the question is whether it shows unique benefits. Instead, what about oatmeal or whole wheat?

Well, first, researchers needed to design an artery-crippling meal, high in saturated fat. They went with a Haagen Daaz, coconut cream, and egg milkshake given with a bowl of oatmeal or “a comparable bowl of whole rolled wheat.” What do you think happened? Do you think these whole grains blocked the artery-damaging effects like the brown rice did? The whole oats worked, but the whole wheat did not. So, one could argue that brown rice may have an edge over whole wheat. Do oats also have that beneficial long-term effect that brown rice did? The benefit was of a similar magnitude but did not reach statistical significance.

So, what’s the bottom line? Until we know more, my current thinking on the matter is that if you really like rice, you can moderate your risk by cutting down, choosing lower arsenic varieties, and cooking it in a way to lower exposure even further. But, if you like other whole grains just as much and don’t really care if you have rice versus quinoa or another grain, I’d choose the lower arsenic option.

Tada! Done with arsenic in the food supply—for now. Should the situation change, I’ll produce another video on the latest news. Make sure you’re subscribed so you don’t miss any updates.


Here are all 13 videos in the series, in case you missed any or want to go back and review:

And you may be interested in Benefits of Turmeric for Arsenic Exposure.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Cancer Risk from Arsenic in Rice and Seaweed

A daily half-cup of cooked rice may carry a hundred times the acceptable cancer risk of arsenic. What about seaweed from the coast of Maine?

“At one point during the reign of King Cotton, farmers in the south central United States controlled boll weevils with arsenic-based pesticides, and residual arsenic still contaminates the soil.” Different plants have different reactions to arsenic exposure. Tomatoes, for example, don’t seem to accumulate much arsenic, but rice plants are really good at sucking it out of the ground—so much so that rice can be used for “arsenic phytoremediation,” meaning you can plant rice on contaminated land as a way to clear arsenic from the soil. Of course, you’re then supposed to throw the rice—and the arsenic—away. But in the South, where 80 percent of U.S. rice is grown, we instead feed it to people.

As you can see at 0:52 in my video Cancer Risk from Arsenic in Rice and Seaweed, national surveys have shown that most arsenic exposure has been measured coming from the meat in our diet, rather than from grains, with most from fish and other seafood. Well, given that seafood is contributing 90 percent of our arsenic exposure from food, why are we even talking about the 4 percent from rice?

The arsenic compounds in seafood are mainly organic—used here as a chemistry term having nothing to do with pesticides. Because of the way our body can deal with organic arsenic compounds, “they have historically been viewed as harmless.” Recently, there have been some questions about that assumption, but there’s no question about the toxicity of inorganic arsenic, which you get more of from rice.

As you can see at 1:43 in my video, rice contains more of the toxic inorganic arsenic than does seafood, with one exception: Hijiki, an edible seaweed, is a hundred times more contaminated than rice, leading some researchers to refer to it as the “so-called edible hijiki seaweed.” Governments have started to agree. In 2001, the Canadian government advised the public not to eat hijiki, followed by the United Kingdom, the European Commission, Australia, and New Zealand. The Hong Kong Centre for Food Safety advised the public not to eat hijiki and banned imports and sales of it. Japan, where there is actually a hijiki industry, just advised moderation.

What about seaweed from the coast of Maine—domestic, commercially harvested seaweed from New England? Thankfully, only one type, a type of kelp, had significant levels of arsenic. But, it would take more than a teaspoon to exceed the provisional daily limit for arsenic, and, at that point, you’d be exceeding the upper daily limit for iodine by about 3,000 percent, which is ten times more than reported in a life-threatening case report attributed to a kelp supplement.

I recommend avoiding hijiki due to its excess arsenic content and avoiding kelp due to its excess iodine content, but all other seaweeds should be fine, as long as you don’t eat them with too much rice.

In the report mentioned earlier where we learned that rice has more of the toxic inorganic arsenic than fish, we can see that there are 88.7 micrograms of inorganic arsenic per kilogram of raw white rice. What does that mean? That’s only 88.7 parts per billion, which is like 88.7 drops of arsenic in an Olympic-size swimming pool of rice. How much cancer risk are we talking about? To put it into context, the “usual level of acceptable risk for carcinogens” is one extra cancer case per million. That’s how we typically regulate cancer-causing substances. If a chemical company wants to release a new chemical, we want them to show that it doesn’t cause more than one in a million excess cancer cases.

The problem with arsenic in rice is that the excess cancer risk associated with eating just about a half cup of cooked rice a day could be closer to one in ten thousand, not one in a million, as you can see at 4:07 in my video. That’s a hundred times the acceptable cancer risk. The FDA has calculated that one serving a day of the most common rice, long grain white, would cause not 1 in a million extra cancer cases, but 136 in a million.

And that’s just the cancer effects of arsenic. What about all the non-cancer effects? The FDA acknowledges that, in addition to cancer, the toxic arsenic found in rice “has been associated with many non-cancer effects, including ischemic heart disease, diabetes, skin lesions, renal [kidney] disease, hypertension, and stroke.” Why, then, did the FDA only calculate the cancer risks of arsenic? “Assessing all the risks associated with inorganic arsenic would take considerable time and resources and would delay taking any needed action to protect public health” from the risks of rice.

“Although physicians can help patients reduce their dietary arsenic exposure, regulatory agencies, food producers, and legislative bodies have the most important roles” in terms of public health-scale changes. “Arsenic content in U.S.-grown rice has been relatively constant throughout the last 30 years,” which is a bad thing.

“Where grain arsenic concentration is elevated due to ongoing contamination, the ideal scenario is to stop the contamination at the source.” Some toxic arsenic in foods is from natural contamination of the land, but soil contamination has also come from the dumping of arsenic-containing pesticides, as well as the use of arsenic-based drugs in poultry production and then the spreading of arsenic-laced chicken manure on the land. Regardless of why south central U.S. rice paddies are so contaminated, we shouldn’t be growing rice in arsenic-contaminated soil.

What does the rice industry have to say for itself? Well, it started a website called ArsenicFacts. Its main argument appears to be that arsenic is everywhere, we’re all exposed to it every day, and it’s in most foods. But shouldn’t we try to cut down on the most concentrated sources? Isn’t that like saying look, diesel exhaust is everywhere, so why not suck on a tailpipe? The industry website quotes a nutrition professor saying, “All foods contain arsenic. So, if you eliminate arsenic from your diet, you will decrease your risk…and you’ll die of starvation.” That’s like Philip Morris saying that the only way to completely avoid secondhand smoke is to never breathe—but then you’ll asphyxiate, so you might as well just start smoking yourself. If you can’t avoid it, you might as well consume the most toxic source you can find?!

That’s the same tack the poultry industry took. Arsenic and chicken? “No need to worry” because there’s a little arsenic everywhere. That’s why it’s okay the industry fed chickens arsenic-based drugs for 70 years. If you can’t beat ’em, join ’em.

How can the rice industry get away with selling a product containing a hundred times the acceptable cancer risk? I cover that and so much more in my other videos on arsenic and rice, which also include concrete recommendations on how to mediate your risk.


Check out:

Pesticides were not the only source of arsenic. Poultry poop, too, if you can believe it! I cover that story in Where Does the Arsenic in Chicken Come From? and Where Does the Arsenic in Rice, Mushrooms, and Wine Come From?.

Chronic low-dose arsenic exposure is associated with more than just cancer. See The Effects of Too Much Arsenic in the Diet.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

The Effects of Too Much Arsenic in the Diet

Even at low-level exposure, arsenic is not just a class I carcinogen, but may also impair our immune function and increase our risk of cardiovascular disease and diabetes.

When people hear about arsenic, they think of it as an acute poison, and, indeed, a tiny amount—a hundred milligrams, about one-tenth the weight of a paperclip—could kill you in an hour. But, there is also chronic arsenic poisoning, where even a dose 10,000 times as small can be harmful if you’re exposed day-after-day for years at a time as I discuss in my video The Effects of Too Much Arsenic in the Diet. Chief among the concerns is cancer.

Arsenic is classified as a class I carcinogen, which is the highest level and includes things known to cause cancer in humans. Other class I carcinogens are asbestos, cigarette smoke, formaldehyde, plutonium, and processed meat (the consumption of bacon, ham, hot dogs, deli meat, and the like). So, arsenic is pretty bad, to say the least, implicated in tens of thousands—or even hundreds of thousands—of cancer cases worldwide every year.

Of course, cancer is our number-two killer. What about heart disease, our leading cause of death? “Long-term exposure to low to moderate arsenic levels was associated with cardiovascular disease incidence and mortality,” meaning heart attacks and strokes.

Arsenic is also considered an immunotoxicant, meaning it’s toxic to our immune system. How do we know that? There’s a virus called varicella, which is what causes chickenpox—the first time we get it. Our immune system is able to stamp it down but not stamp it out. The virus retreats into our nerve cells where it lies in wait for our immune function to dip. And, when it does, the virus re-emerges and causes a disease called shingles. We’ve all been exposed to the virus, but only about one in three of us will get shingles because our immune system is able to keep it at bay. However, the virus can slip its muzzle as we get older or immunosuppressed, for instance, if we’re given arsenic chemotherapy. Shingles is a common side effect, because the arsenic drugs not only kill the cancer but also some of our immune cells, too. That’s at high doses, though. Might even low doses of arsenic, like the kind we’re exposed to in our daily diet, impact our immune function? Researchers tested the levels of arsenic in the urine of thousands of Americans, along with their levels of anti-virus antibodies, and, indeed, they found that the more arsenic the subjects had flowing through their bodies, the lower their defenses.

And, if you’re pregnant, arsenic can pass to your baby, possibly increasing the risk of miscarriage or infant mortality, and “may affect an infant’s immune development and susceptibility to infections early in life.” Indeed, a study out of New Hampshire on infant infections in relation to prenatal arsenic exposure found that the more arsenic the mom was exposed to during pregnancy, the higher the baby’s risk of infection during infancy. However, “it’s unknown whether arsenic-induced epigenetic changes are transgenerational”—that is, whether changes in gene expression can impact the health of not only your own children but your grandchildren as well. Regardless, arsenic exposure isn’t good for mom’s own health, as it is associated with increasing blood pressure.

Hold on. If arsenic suppresses immune system function, then, as a silver lining, would we, for example, have fewer allergies, which is a kind of over-reaction of the immune system? Apparently not. Those with higher arsenic levels tend to have higher rates of food allergies, tend not to sleep as well, and tend not to feel as well. When people were asked how they would rate their health, those reporting “excellent” or “very good” tended to have lower levels of arsenic, compared to those who reported their general health condition as “good,” “fair,” or “poor,” who tended to have higher arsenic levels.

What about diabetes? You can see the results of two dozen population studies on arsenic exposure and confirmed diabetes at 4:07 in my video. Any result above one suggests increased risk for diabetes, and any result below one suggests lower risk. The findings? “Our results support an association between ingested arsenic and DM [diabetes] in humans.” Population studies can’t prove cause and effect, though. “While it would be nice to demonstrate a cause and effect relationship…is it necessary?”

We know arsenic is a carcinogen. We know it causes cancer. What more do we need to take steps to decrease our exposure?

Where is arsenic found in our diet? See my videos Where Does the Arsenic in Chicken Come From?  and Where Does the Arsenic in Rice, Mushrooms, and Wine Come From?.


 Ready for a deep dive into the rice issue? Check out:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

 

 

 

Açaí vs. Wild Blueberries for Artery Function

“Plant-based diets…have been found to reduce the risk of cardiovascular disease” and some of our other leading causes of death and disability. “Studies have shown that the longest living and least dementia-prone populations subsist on plant-based diets.” So why focus on açaí berries, just one plant, for brain health and performance?

Well, “foods rich in polyphenols…improve brain health,” and açaí berries contain lots of polyphenols and antioxidants, so perhaps that’s why they could be beneficial. If you’re only looking at polyphenols, though, there are more than a dozen foods that contain more per serving, like black elderberry, regular fruits like plums, flaxseeds, dark chocolate, and even just a cup of coffee.

As you can see at 1:02 in my video The Benefits of Açaí vs. Blueberries for Artery Function, in terms of antioxidants, açaí berries may have ten times more antioxidant content than more typical fruits, like peaches and papayas, and five times more antioxidants than strawberries. But blackberries, for instance, appear to have even more antioxidants than açaí berries and are cheaper and more widely available.

Açaí berries don’t just have potential brain benefits, however. Might they also protect the lungs against harm induced by cigarette smoke? You may remember the study where the addition of açaí berries to cigarettes protected against emphysema—in smoking mice, that is. That’s not very helpful. There is a long list of impressive-looking benefits until you dig a little deeper. For example, I was excited to see a “[r]eduction of coronary disease risk due to the vasodilation effect” of açaí berries, but then I pulled the study and found they were talking about a vasodilator effect…in the mesenteric vascular bed of rats. There hadn’t been any studies on açaí berries and artery function in humans until a study published in 2016.

Researchers gave overweight men either a smoothie containing about two-thirds of a cup of frozen açaí pulp and half a banana or an artificially colored placebo smoothie containing the banana but no açaí. As you can see at 2:26 in my video, within two hours of consumption of their smoothie, the açaí group had a significant improvement in artery function that lasted for at least six hours, a one or two point bump that is clinically significant. In fact, those walking around with just one point higher tend to go on to suffer 13 percent fewer cardiovascular events like fatal heart attacks.

As I show at 2:52 in my video, you can get the same effect from wild blueberries, though: about a one-and-a-half-point bump in artery function two hours after blueberry consumption. This effect peaks then plateaus at about one and a half cups of blueberries, with two and a half cups and three and a half cups showing no further benefits.

What about cooked blueberries? As you can see at 3:12 in my video, if you baked the blueberries into a bun, like a blueberry muffin, you get the same dramatic improvement in artery function.

Cocoa can do it, too. As shown at 3:30 in my video, after having one tablespoon of cocoa, you gain about one point, and two tablespoons gives you a whopping four points or so, which is double what you get with açaí berries.

One and a quarter cups’ worth of multicolored grapes also give a nice boost in artery function, but enough to counter an “acute endothelial insult,” a sudden attack on the vulnerable inner layer of our arteries? Researchers gave participants a “McDonald’s sausage egg breakfast sandwich and two hash browns.” They weren’t messing around! As you can see at 3:56 in my video, without the grapes, artery function was cut nearly in half within an hour, and the arteries stayed stiffened and crippled three hours later. But when they ate that McMuffin with all those grapes, the harmful effect was blunted.

Eat a meal with hamburger meat, and artery function drops. But if you eat that same meal with some spices, including a teaspoon and a half of turmeric, artery function actually improves.

What about orange juice? Four cups a day of commercial orange juice from concentrate for four weeks showed no change in artery function. What about freshly squeezed orange juice? Still nothing. That’s one of the reasons berries, not citrus, are the healthiest fruits.

For a beverage that can improve your artery function, try green tea. Two cups of green tea gives you that same effect we saw with cocoa, gaining nearly four points within just 30 minutes. And, as you can see at 5:05 in my video, that same crazy effect is also seen with black tea, with twice as powerful an effect as the açaí berries.

So, why all the focus on just that one plant? Why açaí berries? Well, the real reason may be because the author owns a patent on an açaí-based dietary supplement.


How do the antioxidant effects of açaí berries compare to applesauce? See The Antioxidant Effects of Açaí vs. Apples.

What about the effects of other foods on artery function? Coronary artery disease is, after all, our leading cause of death for men and women. See:

What else can blueberries do? Check out:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Kidney Toxins Created by Meat Consumption

As I discuss in my video How to Treat Heart Failure and Kidney Failure with Diet, one way a diet rich in animal-sourced foods like meat, eggs, and cheese may contribute to heart disease, stroke, and death is through the production of an atherosclerosis-inducing substance called TMAO. With the help of certain gut bacteria, the choline and carnitine found concentrated in animal products can get converted into TMAO. But, wait a second. I thought atherosclerosis, or hardening of the arteries, was about the buildup of cholesterol. Is that not the case?

“Cholesterol is still king,” but TMAO appears to accelerate the process. It seems that TMAO appears to increase the ability of inflammatory cells within the atherosclerotic plaque in the artery walls to bind to bad LDL cholesterol, “which makes the cells more prone to gobble up cholesterol.” So TMAO is just “another piece to the puzzle of how cholesterol causes heart disease.”

What’s more, TMAO doesn’t just appear to worsen atherosclerosis, contributing to strokes and heart attacks. It also contributes to heart and kidney failure. If you look at diabetics after a heart attack, a really high-risk group, nearly all who started out with the most TMAO in their bloodstream went on to develop heart failure within 2,000 days, or about five years. In comparison, only about 20 percent of those starting out with medium TMAO levels in the blood went into heart failure and none at all in the low TMAO group, as you can see at 1:21 in my video.

So, those with heart failure have higher levels of TMAO than controls, and those with worse heart failure have higher levels than those with lesser stage heart disease. If you follow people with heart failure over time, within six years, half of those who started out with the highest TMAO levels were dead. This finding has since been replicated in two other independent populations of heart failure patients.

The question is, why? It’s probably unlikely to just be additional atherosclerosis, since that takes years. For most who die of heart failure, their heart muscle just conks out or there’s a fatal heart rhythm. Maybe TMAO has toxic effects beyond just the accelerated buildup of cholesterol.

What about kidney failure? People with chronic kidney disease are at a particularly “increased risk for the development of cardiovascular disease,” thought to be because of a diverse array of uremic toxins. These are toxins that would normally be filtered out by the kidneys into the urine but may build up in the bloodstream as kidney function declines. When we think of uremic toxins, we usually think of the toxic byproducts of protein putrefying in our gut, which is why specially formulated plant-based diets have been used for decades to treat chronic kidney failure. Indeed, those who eat vegetarian diets form less than half of these uremic toxins.

Those aren’t the only uremic toxins, though. TMAO, which, as we’ve discussed, comes from the breakdown of choline and carnitine found mostly in meat and eggs, may be increasing heart disease risk in kidney patients as well. How? “The cardiovascular implication of TMAO seems to be due to the downregulation of reverse cholesterol transport,” meaning it subverts our own body’s attempts at pulling cholesterol out of our arteries.

And, indeed, the worse our kidney function gets, the higher our TMAO levels rise, and those elevated levels correlate with the amount of plaque clogging up their arteries in their heart. But once the kidney is working again with a transplant, your TMAO levels can drop right back down. So, TMAO was thought to be a kind of biomarker for declining kidney function—until a paper was published from the Framingham Heart Study, which found that “elevated choline and TMAO levels among individuals with normal renal [kidney] function predicted increased risk for incident development of CKD,” chronic kidney disease. This suggests that TMAO is both a biomarker and itself a kidney toxin.

Indeed, when you follow kidney patients over time and assess their freedom from death, those with higher TMAO, even controlling for kidney function, lived significantly shorter lives, as you can see at 4:44 in my video. This indicates this is a diet-induced mechanism for progressive kidney scarring and dysfunction, “strongly implying the need to focus preventive efforts on dietary modulation,” but what might that look like? Well, maybe we should reduce “dietary sources of TMAO generation, such as some species of deep-sea fish, eggs, and meat.”

It also depends on what kind of gut bacteria you have. You can feed a vegan a steak, and they still don’t really make any TMAO because they haven’t been fostering the carnitine-eating bacteria. Researchers are hoping, though, that one day, they’ll find a way to replicate “the effects of the vegetarian diet…by selective prebiotic, probiotic, or pharmacologic therapies.”


For more on this revolutionary TMAO story, see:

For more on kidney failure, see Preventing Kidney Failure Through Diet and Treating Kidney Failure Through Diet.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

What White Blood Cell Count Should We Shoot for?

At the start of my video What Does a Low White Blood Cell Count Mean?, you can see what it looks like when you take a drop of blood, smear it between two pieces of glass, and view at it under a microscope: a whole bunch of little, round, red blood cells and a few big, white blood cells. Red blood cells carry oxygen, while white blood cells are our immune system’s foot soldiers. We may churn out 50 billion new white blood cells a day. In response to inflammation or infection, that number can shoot up to a 100 billion or more. In fact, pus is largely composed of: millions and millions of white blood cells.

Testing to find out how many white blood cells we have at any given time is one of the most common laboratory tests doctors order. It’s ordered it hundreds of millions of times a year. If, for example, you end up in the emergency room with abdominal pain, having a white blood cell count above about 10 billion per quart of blood may be a sign you have appendicitis. Most Americans fall between 4.5 and 10, but most Americans are unhealthy. Just because 4.5 to 10 is typical doesn’t mean it’s ideal. It’s like having a “normal” cholesterol level in a society where it’s normal to die of heart disease, our number-one killer. The average American is overweight, so if your weight is “normal,” that’s actually a bad thing.

In fact, having excess fat itself causes inflammation within the body, so it’s no surprise that those who are obese walk around with two billion more white cells per quart of blood. Given that, perhaps obese individuals should have their own “normal” values. As you can see at 2:06 in my video, if someone with a 47-inch waist walks into the ER with a white blood cell count of 12, 13, or even 14, they may not have appendicitis or an infection. That may just be their normal baseline level, given all the inflammation they have in their body from the excess fat. So, normal levels are not necessarily healthy levels.

It’s like smoking. As you can see at 2:31 in my video, if you test identical twins and one smokes but the other doesn’t, the smoker is going to end up with a significantly higher white cell count. In Japan, for example, as smoking rates have steadily dropped, so has the normal white count range. In fact, it’s dropped such that about 8 percent of men who have never smoked would now be flagged as having abnormally low white counts if you used a cut-off of 4. But, when that cut-off of 4 was set, most people were smoking. So, maybe 3 would be a better lower limit. The inflammation caused by smoking may actually be one of the reasons cigarettes increase the risk of heart attacks, strokes, and other inflammatory diseases. So, do people who have lower white counts have less heart disease, cancer, and overall mortality? Yes, yes, and yes. People with lower white blood cell counts live longer. Even within the normal range, every one point drop may be associated with a 20 percent drop in the risk of premature death.

As you can see at 3:39 in my video, there is an exponential increase in risk in men as white count goes up, even within the so-called normal range, and the same is found for women. The white blood cell count is a “stable, well-standardized, widely available and inexpensive measure of systemic inflammation.” In one study, half of the women around 85 years of age who had started out with white counts under 5.6 were still alive, whereas 80 percent of those who started out over 7 were dead, as you can see at 4:05 in my video—and white blood cell counts of 7, 8, 9, or even 10 would be considered normal. Being at the high end of the normal range may place one at three times the risk of dying from heart disease compared to being at the lower end.

The same link has been found for African-American men and women, found for those in middle age, found at age 75, found at age 85, and found even in our 20s and 30s: a 17 percent increase in coronary artery disease incidence for each single point higher.

As you can see at 5:00 in my video, the higher your white count, the worse your arterial function may be and the stiffer your arteries may be, so it’s no wonder white blood cell count is a useful predictor of high blood pressure and artery disease in your heart, brain, legs, and neck. Even diabetes? Yes, even diabetes, based on a compilation of 20 different studies. In fact, it may be associated with everything from fatty liver disease to having an enlarged prostate. And, having a higher white blood cell count is also associated with an increased risk of dying from cancer. So, what would the ideal range be? I cover that in my video What Is the Ideal White Blood Cell Count?.

A higher white blood cell count may be an important predictor for cardiovascular disease incidence and mortality, decline in lung function, cancer mortality, all-cause mortality, heart attacks, strokes, and premature death in general. This is no surprise, as the number of white blood cells we have circulating in our bloodstreams are a marker of systemic inflammation. Our bodies produce more white blood cells day to day in response to inflammatory insults.

We’ve known about this link between higher white counts and heart attacks since the 1970s, when we found that higher heart attack risk was associated with higher white blood cell counts, higher cholesterol levels, and higher blood pressures, as you can see at 0:53 in my video What Is the Ideal White Blood Cell Count?. This has been found in nearly every study done since then. There are decades of studies involving hundreds of thousands of patients showing dramatically higher mortality rates in those with higher white counts. But why? Why does white blood cell count predict mortality? It may be because it’s a marker of inflammation and oxidation in the body. In fact, it may even be a biomarker for how fast we are aging. It may be more than just an indicator of inflammation—it may also be an active player, contributing directly to disease via a variety of mechanisms, including the actual obstruction of blood flow.

The average diameter of a white blood cell is about seven and a half micrometers, whereas our tiniest vessels are only about five micrometers wide, so the white blood cell has to squish down into a sausage shape in order to squeeze through. When there’s inflammation present, these cells can get sticky. As you can see at 2:20 in my video, a white blood cell may plug up a vessel as it exits a small artery and tries to squeeze into a capillary, slowing down or even momentarily stopping blood flow. And, if it gets stuck there, it can end up releasing all of its internal weaponry, which is normally reserved for microbial invaders, and damage our blood vessels. This may be why in the days leading up to a stroke or heart attack, you may find a spike in the white cell count.

Whether white count is just a marker of inflammation or an active participant, it’s better to be on the low side. How can we reduce the level of inflammation in our body? Staying away from even second-hand smoke can help drop your white count about half of a point. Those who exercise also appear to have an advantage, but you don’t know if it’s cause and effect unless you put it to the test. In one study, two months of Zumba classes—just one or two hours a week—led to about a point and a half drop in white count. In fact, that may be one of the reasons exercise is so protective. But is that just because they lost weight?

Fitness and fatness both appear to play a role. More than half of obese persons with low fitness—51.5 percent—have white counts above 6.6, but those who are more fit or who have less fat are less likely to have counts that high, as you can see at 3:47 in my video. Of course, that could just be because exercisers and leaner individuals are eating healthier, less inflammatory diets. How do we know excess body fat itself increases inflammation, increases the white count? You’d have to find some way to get people to lose weight without changing their diet or exercise habit. How’s that possible? Liposuction. If you suck about a quart of fat out of people, you can significantly drop their white count by about a point. Perhaps this should get us to rethink the so-called normal reference range for white blood cell counts. Indeed, maybe we should revise it downward, like we’ve done for cholesterol and triglycerides.

Until now, we’ve based normal values on people who might be harboring significant background inflammatory disease. But, if we restrict it to those with normal C-reactive protein, another indicator of inflammation, then instead of “normal” being 4.5 to 10, perhaps we should revise it closer to 3 to 9.

Where do the healthiest populations fall, those not suffering from the ravages of chronic inflammatory diseases, like heart disease and common cancers? Populations eating diets centered around whole plant foods average about 5, whereas it was closer to 7 or 8 in the United States at the time. How do we know it isn’t just genetic? As you can see at 5:38 in my video, if you take those living on traditional rural African diets, who have white blood cell counts down around 4 or 5, and move them to Britain, they end up closer to 6, 7, or even 8. Ironically, the researchers thought this was a good thing, referring to the lower white counts on the “uncivilized” diet as neutropenic, meaning having too few white blood cells. They noted that during an infection or pregnancy, when more white cells are needed, the white count came right up to wherever was necessary. So, the bone marrow of those eating traditional plant-based diets had the capacity to create as many white cells as needed but “suffers from understimulation.”

As you can see at 6:26 in my video, similar findings were reported in Western plant eaters, with an apparent stepwise drop in white count as diets got more and more plant based, but could there be non-dietary factors, such as lower smoking rates, in those eating more healthfully? What we need is an interventional trial to put it to the test, and we got one: Just 21 days of removing meat, eggs, dairy, alcohol, and junk affected a significant drop in white count, even in people who started out down at 5.7.

What about patients with rheumatoid arthritis who started out even higher, up around 7? As you can see at 7:03 in my video, there was no change in the control group who didn’t change their diet, but there was a 1.5 point drop within one month on whole food plant-based nutrition. That’s a 20 percent drop. That’s more than the drop-in inflammation one might get quitting a 28-year pack-a-day smoking habit. The most extraordinary drop I’ve seen was in a study of 35 asthmatics. After four months of a whole food plant-based diet, their average white count dropped nearly 60 percent, from around 12 down to 5, though there was no control group nor enough patients to achieve statistical significance.

If white blood cell count is such a clear predictor of mortality and is so inexpensive, reliable, and available, why isn’t it used more often for diagnosis and prognosis? Maybe it’s a little too inexpensive. The industry seems more interested in fancy new risk factors it can bill for.

I touch on the health of the rural Africans I discussed in How Not to Die from Heart Disease.


For more on fighting inflammation, see:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

What About the Trans Fat in Animal Fat?

The years of healthy life lost due to our consumption of trans fats are comparable to the impact of conditions like meningitis, cervical cancer, and multiple sclerosis. But, if “food zealots” get their wish in banning added trans fats, what’s next? I explore this in my video Banning Trans Fat in Processed Foods but Not Animal Fat.

Vested corporate interests rally around these kinds of slippery slope arguments to distract from the fact that people are dying. New York Mayor Bloomberg was decried as a “meddling nanny” for his trans fat ban and attempt to cap soft drink sizes. How dare he try to manipulate consumer choice! But isn’t that what the food industry has done? “Soft drink portion sizes have grown dramatically, along with Americans’ waistlines.” In 1950, a 12-ounce soda was the king-sized option. Now, it’s the kiddie size. Similarly, with trans fats, it was the industry that limited our choice by putting trans fats into everything without even telling us. Who’s the nanny now?

New York City finally won its trans fat fight, preserving its status as a public health leader. “For example, it took decades to achieve a national prohibition of lead paint, despite unequivocal evidence of harm,” but New York City’s Board of Health led the way, banning it “18 years before federal action.”

There’s irony in the slippery slope argument: First, they’ll come for your fries; next, they’ll come for your burger. After the trans fat oil ban, one of the only remaining sources of trans fat is in the meat itself. “Trans fats naturally exist in small amounts in the fat in meat and milk,” as I’ve discussed before in my video Trans Fat in Meat and Dairy. Before the trans fat ban, animal products only provided about one fifth of America’s trans fat intake, but since the U.S. trans fat ban exempts animal products, they will soon take over as the leading source. As you can see at 2:09 in Banning Trans Fat in Processed Foods but Not Animal Fat, now that added trans fats are banned in Denmark, for example, the only real trans fat exposure left is from animal products found in the U.S. dairy, beef, chicken fat, turkey meat, lunch meat, and hot dogs, with trace amounts in vegetable oils due to the refining process.

The question is: Are animal trans fats as bad as processed food trans fats? As you can see at 2:38 in my video, a compilation of randomized interventional trials found that they both make bad cholesterol go up and they both make good cholesterol go down. So, both animal trans fats and processed food trans fats make the ratio of bad to good cholesterol go up—which is bad. Therefore, all trans fats cause negative effects “irrespective of their origin.” The researchers suspect that also removing natural trans fats from the diet could prevent tens of thousands of heart attacks, but unlike processed foods, you can’t remove trans fats from milk and meat because trans fats are there naturally.

The livestock industry suggests that a little bit of their trans fats might not be too bad, but you saw the same everything-in-moderation argument coming from the Institute of Shortening and Edible Oils after industrial trans fats were first exposed as a threat. The bottom line is “that intake of all sources of trans fat should be minimized.” The trans fat in processed foods can be banned, and just adhering to the current dietary guidelines to restrict saturated fat intake, which is primarily found in meat and dairy, would automatically cut trans fat intake from animal fats.

The reason no progress may have been made on animal trans fat reduction in Denmark is because The Danish Nutrition Council that pushed for the trans fat ban was a joint initiative of The Danish Medical Association and The Danish Dairy Board. They recognized that “the economic support from The Danish Dairy Council could be perceived as problematic” from a scientific integrity point of view, but, not to worry—“The Danish Medical Association expanded the Executive Board and the funding members to also include the Danish pork industry, the Danish meat industry, The Poultry and Egg Council and The Danish Margarine Industry Association.”

If people want to eat trans fat, isn’t that their right? Yes, but only if they’re informed about the risks—yet The Food Industry Wants the Public Confused About Nutrition.

For more on the industry pushback, see my video Controversy Over the Trans Fat Ban.

There does not appear to be a safe level of exposure to trans fat—or to saturated fat or dietary cholesterol, for that matter. See Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero.


If you find these videos about industry influence on public policy compelling, check out my many others, including:

Note that the concept of raising or lowering HDL (the so-called good cholesterol) playing a causal role in heart disease has come into question. See Coconut Oil and the Boost in HDL “Good” Cholesterol.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

The Food Industry’s “model of systemic dishonesty”

In 1993, the Harvard Nurses’ Health Study found that a high intake of trans fat may increase the risk of heart disease by 50 percent. That’s where the trans fat story started in Denmark, ending a decade later with a ban on added trans fats in 2003. It took another ten years before the United States even started considering a ban. All the while, trans fats were killing tens of thousands of Americans every year. With so many people dying, why did it take so long for the United States to even suggest taking action? I explore this in my video Controversy Over the Trans Fat Ban.

One can look at the fight over New York City’s trans fat ban for a microcosm of the national debate. Not surprisingly, opposition came from the food industry, complaining about “government intrusion” and “liken[ing] the city to a ‘nanny state.’” “Are trans fat bans…the road to food fascism?”

A ban on added trans fats might save 50,000 American lives every year, which could save the country tens of billions of dollars in healthcare costs, but not so fast! If people eating trans fat die early, think about how much we could save on Medicare and Social Security. Indeed, “smokers actually cost society less than nonsmokers, because smokers die earlier.” So, “we should be careful about making claims about the potential cost-savings of trans fat bans….more research is needed on the effects of these policies, including effects on the food industry.” Yes, we might save 50,000 lives a year, but we can’t forget to think about the “effects on the food industry”!

How about “education and product labeling” rather than “the extreme measure of banning trans fats”? As leading Danish cardiologist “puts it bluntly, ‘Instead of warning consumers about trans fats and telling them what they are, we’ve [the Danes] simply removed them.’” But we’re Americans! “As they say in North America: ‘You can put poison in food if you label it properly.’”

People who are informed and know the risks should be able to eat whatever they want, but that assumes they’re given all the facts, which doesn’t always happen “due to deception and manipulation by food producers and retailers.” And, not surprisingly, it’s the unhealthiest of foods that are most commonly promoted using deceptive marketing. It’s not that junk food companies are evil or want to make us sick. “The reason is one of simple economics”—processed foods simply “offer higher profit margins and are shelf-stable, unlike fresh foods such as fruit and vegetables.” The food industry’s “model of systemic dishonesty,” some argue, “justifies some minimal level of governmental intervention.”

But is there a slippery slope? “Today, trans fats; tomorrow, hot dogs.” Or, what about the reverse? What if the government makes us eat broccoli? This argument actually came up in the Supreme Court case over Obamacare. As Chief Justice Roberts said, Congress could start ordering everyone to buy vegetables, a concern Justice Ginsburg labeled “the broccoli horrible.” Hypothetically, Congress could compel the American public to go plant-based, however, no one can offer the “hypothetical and unreal possibility…of a vegetarian state” as a credible argument. “Judges and lawyers live on the slippery slope of analogies; they are not supposed to ski it to the bottom,” said one legal scholar.

If anything, what about the slippery slope of inaction? “Government initially defaulted to business interests in the case of tobacco and pursued weak and ineffective attempts at education” to try to counter all the tobacco industry lies. Remember what happened? “The unnecessary deaths could be counted in the millions. The U.S. can ill afford to repeat this mistake with diet.”

Once added trans fats are banned, the only major source in the American diet will be the natural trans fats found in animal fat. For more on this, see Banning Trans Fat in Processed Foods but Not Animal Fat and Trans Fat in Meat and Dairy.

Ideally how much trans fat should we eat a day? Zero, and the same goes for saturated fat and cholesterol. See Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero, Good, Great, Bad, and Killer Fats, and Lipotoxicity: How Saturated Fat Raises Blood Sugar.


More on industry hysterics and manipulation in:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

How to Treat Polycystic Ovary Syndrome (PCOS) with Diet

Given the role that oxidant free radicals are thought to play in aging and disease, one reason fruits and vegetables may be so good for us is that they contain antioxidant compounds. As you can see at 0:20 in my video Benefits of Marjoram for Polycystic Ovary Syndrome (PCOS), different vegetables and herbs have different antioxidant content. When making a salad, for example, spinach, arugula, or red leaf lettuce may provide twice the antioxidants as butterhead lettuce, and choosing purple cabbage over green, or red onions over white can also boost the salad’s antioxidant power.

Fresh herbs are so powerful that even a small amount may double or even quadruple the antioxidant power of the entire meal. For instance, as you can see at 0:50 in my video, the total antioxidants in a simple salad of lettuce and tomato jump up by adding just a tablespoon of lemon balm leaves or half a tablespoon of oregano or mint. Adding marjoram, thyme, or sage not only adds great flavor to the salad, but effectively quadruples the antioxidant content at the same time, and adding a little fresh garlic or ginger to the dressing ups the antioxidant power even more.

Herbs are so antioxidant-rich that researchers decided to see if they might be able to reduce the DNA-damaging effects of radiation. Radioactive iodine is sometimes given to people with overactive thyroid glands or thyroid cancer to destroy part of the gland or take care of any remaining tumor cells after surgery. For days after the isotope injection, patients become so radioactive they are advised not to kiss or sleep close to anyone, including their pets, and if they breathe on a phone, they’re advised to wipe it “carefully” or cover it “with an easily removed plastic bag.” Other recommendations include “avoid[ing] splatter of radioactive urine,” not going near your kids, and basically just staying away from others as much as possible.

The treatment can be very effective, but all that radiation exposure appears to increase the risk of developing new cancers later on. In order to prevent the DNA damage associated with this treatment, researchers tested the ability of oregano to protect chromosomes of human blood cells in vitro from exposure to radioactive iodine. As you can see at 2:25 in my video, at baseline, about 1 in 100 of our blood cells show evidence of chromosomal damage. If radioactive iodine is added, though, it’s more like 1 in 8. What happens if, in addition to the radiation, increasing amounts of oregano extract are added? Chromosome damage is reduced by as much 70 percent. Researchers concluded that oregano extract “significantly protects” against DNA damage induced by the radioactive iodine in white blood cells. This was all done outside the body, though, which the researchers justified by saying it wouldn’t be particularly ethical to irradiate people for experimental research. True, but millions of people have been irradiated for treatment, and researchers could have studied them or, at the very least, they could have just had people eat the oregano and then irradiate their blood in vitro to model the amount of oregano compounds that actually make it into the bloodstream.

Other in vitro studies on oregano are similarly unsatisfying. In a comparison of the effects of various spice extracts, including bay leaves, fennel, lavender, oregano, paprika, parsley, rosemary, and thyme, oregano beat out all but bay leaves in its ability to suppress cervical cancer cell growth in vitro while leaving normal cells alone. But people tend to use oregano orally—that is, they typically eat it—so the relevance of these results are not clear.

Similarly, marjoram, an herb closely related to oregano, can suppress the growth of individual breast cancer cells in a petri dish, as you can see at 3:53 in my video, and even effectively whole human breast tumors grown in chicken eggs, which is something I’ve never seen before. Are there any clinical trials on oregano-family herbs on actual people? The only such clinical, randomized, control study I could find was a study on how marjoram tea affects the hormonal profile of women with polycystic ovary syndrome (PCOS). The most common cause of female fertility problems, PCOS affects up to one in eight young women and is characterized by excessive male hormones, resulting in excess body or facial hair, menstrual irregularities, and cysts in one’s ovaries that show up on ultrasounds.

Evidently, traditional medicine practitioners reported marjoram tea was beneficial for PCOS, but it had never been put to the test…until now. Drinking two daily cups of marjoram tea versus a placebo tea for one month did seem to beneficially affect the subjects’ hormonal profiles, which seems to offer credence to the claims of the traditional medicine practitioners. However, the study didn’t last long enough to confirm that actual symptoms improved as well, which is really what we care about.

Is there anything that’s been shown to help? Well, reducing one’s intake of dietary glycotoxins may help prevent and treat the disease. Over the past 2 decades there has been increasing evidence supporting an important contribution from food-derived advanced glycation end products (AGEs)…[to] increased oxidative stress and inflammation, processes that play a major role in the causation of chronic diseases,” potentially including polycystic ovary syndrome (PCOS). Women with PCOS tend to have nearly twice the circulating AGE levels in their bloodstream, as you can see at 0:33 in my video Best Foods for Polycystic Ovary Syndrome (PCOS). 

PCOS may be the most common hormonal abnormality among young women in the United States and is a common cause of infertility, menstrual dysfunction, and excess facial and body hair. The prevalence of obesity is also higher in women with PCOS. Since the highest AGE levels are found in broiled, grilled, fried, and roasted foods of “mostly animal origin,” is it possible that this causal chain starts with a bad diet? For instance, maybe eating lots of fried chicken leads to obesity, which in turn leads to PCOS. In that case, perhaps what we eat is only indirectly related to PCOS through weight gain. No, because the same link between high AGE levels and PCOS was found in lean women as well.

“As chronic inflammation and increased oxidative stress have been incriminated in the pathophysiology [or disease process] of PCOS, the role of AGEs as inflammatory and oxidant mediators, may be linked with the metabolic and reproductive abnormalities of the syndrome.” Further, the buildup of AGE inside polycystic ovaries themselves suggests a potential role of AGEs contributing to the actual disease process, beyond just some of its consequences.

RAGE is highly expressed in ovarian tissues. The receptor in the body for these advanced glycation end products, the “R” in RAGE, is concentrated in the ovaries, which may be particularly sensitive to its effect. So, AGEs might indeed be contributing to the cause of PCOS and infertility.

Does this mean we should just cut down on AGE-rich foods, such as meat, cheese, and eggs? Or hey, why not come up with drugs that block AGE absorption? We know AGEs have been implicated in the development of many chronic diseases. Specifically, food-derived AGEs play an important role because diet is a major source of these pro-inflammatory AGEs. Indeed, cutting down on these dietary glycotoxins reduces the inflammatory response, but the “argument is often made that stewed chicken would be less tasty than fried chicken…” Why not have your KFC and eat it, too? Just take an AGE-absorption blocking drug every time you eat it to reduce the absorption of the toxins. What’s more, it actually lowers AGE blood levels. This oral absorbent drug, AST-120, is just a preparation of activated charcoal, like what’s used for drug overdoses and when people are poisoned. I’m sure if you took some ipecac with your KFC, your levels would go down, too.

There’s another way to reduce absorption of AGEs, and that’s by reducing your intake in the first place. It’s simple, safe, and feasible. The first step is to stop smoking. The glycotoxins in cigarette smoke may contribute to increased heart disease and cancer in smokers. Then, decrease your intake of high-AGE foods, increase your intake of foods that may help pull AGEs out of your system, like mushrooms, and eat foods high in antioxidants, like berries, herbs, and spices. “Dietary AGE intake can be easily decreased by simply changing the method of cooking from a high dry heat application to a low heat and high humidity…” In other words, move away from broiling, searing, and frying to more stewing, steaming, and boiling.

What we eat, however, may be more important than how we cook it. At 4:00 in my video, I include a table showing the amounts of AGEs in various foods. For instance, boiled chicken contains less than half the glycotoxins of roasted chicken, but even deep-fried potatoes have less than boiled meat. We can also eat foods raw, which doesn’t work as well as for blood pudding, but raw nuts and nut butters may contain about 30 times less glycotoxins than roasted, and we can avoid high-AGE processed foods, like puffed, shredded, and flaked breakfast cereals.

Why does it matter? Because study after study has shown that switching to a low-AGE diet can lower the inflammation within our bodies. Even just a single meal high in AGEs can profoundly impair our arterial function within just two hours of consumption. At 4:54 in my video, you can see the difference between a meal of fried or broiled chicken breast and veggies compared with steamed or boiled chicken breast and veggies. Same ingredients, just different cooking methods. Even a steamed or boiled chicken meal can still impair arterial function, but significantly less than fried or broiled.

“Interestingly, the amount of AGEs administered [to subjects] during the HAGE [high-AGE] intervention was similar to the average estimated daily intake by the general population,” who typically follow the standard American diet. This is why we can decrease inflammation in people by putting them on a low-AGE diet, yet an increase in inflammation is less apparent when subjects switch from their regular diet to one high in AGEs. Indeed, they were already eating a high-AGE diet with so many of these glycotoxins.

Do we have evidence that reducing AGE intake actually helps with PCOS? Yes. Within just two months, researchers found differences from subjects’ baseline diets switched to a high-AGE diet and then to a low-AGE diet, with parallel changes in insulin sensitivity, oxidative stress, and hormonal status, as seen at 5:54 in my video. The take-home learning? Those with PCOS may want to try a low-AGE diet, which, in the study, meant restricting meat to once a week and eating it only boiled, poached, stewed, or steamed, as well as cutting out fast-food-type fare and soda.

What if instead of eating steamed chicken, we ate no meat at all? Rather than measuring blood levels, which vary with each meal, we can measure the level of glycotoxins stuck in our body tissues over time with a high-tech device that measures the amount of light our skin gives off because AGEs are fluorescent. And, not surprisingly, this turns out to be a strong predictor of overall mortality. So, the lower our levels, the better. The “one factor that was consistently associated with reduced [skin fluorescence]: a vegetarian diet.” This “suggests that a vegetarian diet may reduce exposure to preformed dietary AGE…potentially reduc[ing] tissue AGE,” as well as chronic disease risk


What’s so great about antioxidants? See my videos:

Just how many antioxidants do we need? Check out:

For a few simple tips on how to quickly boost the antioxidant content of your food with herbs and spices, see my video Antioxidants in a Pinch.

I touched on the benefits of spearmint tea for PCOS in Enhancing Athletic Performance with Peppermint. Another sorely under-recognized gynecological issue is endometriosis, which I discuss in How to Treat Endometriosis with Seaweed.

Because of AGEs, I no longer toast nuts or buy roasted nut butters, which is disappointing because I really enjoy those flavors so much more than untoasted and unroasted nuts. But, as Dr. McDougall likes to say, nothing tastes as good as healthy feels. For more on why it’s important to minimize our exposure to these toxic compounds, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

 

 

Updating Our Microbiome Software and Hardware

Good bacteria, those living in symbiosis with us, are nourished by fruits, vegetables, grains, and beans, whereas bad bacteria, those in dysbiosis with us and possibly contributing to disease, are fed by meat, junk food and fast food, seafood, dairy, and eggs, as you can see at 0:12 in my video Microbiome: We Are What They Eat. Typical Western diets can “decimate” our good gut flora.

We live with trillions of symbionts, good bacteria that live in symbiosis with us. We help them, and they help us. A month on a plant-based diet results in an increase in the population of the good guys and a decrease in the bad, the so-called pathobionts, the disease-causing bugs. “Given the disappearance of pathobionts from the intestine, one would expect to observe a reduction in intestinal inflammation in subjects.” So, researchers measured stool concentrations of lipocalin-2, “which is a sensitive biomarker of intestinal inflammation.” As you can see at 1:13 in my video, within a month of eating healthfully, it had “declined significantly…suggesting that promotion of microbial homeostasis”—or balance—“by an SVD [strict vegetarian diet] resulted in reduced intestinal inflammation.” What’s more, this rebalancing may have played a role “in improved metabolic and immunological parameters,” that is, in immune system parameters.

In contrast, on an “animal-based diet,” you get growth of disease-associated species like Bilophila wadsworthia, associated with inflammatory bowel disease, and Alistipes putredinis, found in abscesses and appendicitis, and a decrease in fiber-eating bacteria. When we eat fiber, the fiber-munching bacteria multiply, and we get more anti-inflammatory, anti-cancer short-chain fatty acids. When we eat less fiber, our fiber-eating bacteria starve away.

They are what we eat.

Eat a lot of phytates, and our gut flora get really good at breaking down phytates. We assumed this was just because we were naturally selecting for those populations of bacteria able to do that, but it turns out our diet can teach old bugs new tricks. There’s one type of fiber in nori seaweed that our gut bacteria can’t normally breakdown, but the bacteria in the ocean that eat seaweed have the enzyme to do so. When it was discovered that that enzyme was present in the guts of Japanese people, it presented a mystery. Sure, sushi is eaten raw, so some seaweed bacteria may have made it to their colons, but how could some marine bacteria thrive in the human gut? It didn’t need to. It transferred the nori-eating enzyme to our own gut bacteria.

“Consequently, the consumption of food with associated environmental bacteria is the most likely mechanism that promoted this CAZyme [enzyme] update into the human gut microbe”—almost like a software update. We have the same hardware, the same gut bacteria, but the bacteria just updated their software to enable them to chew on something new.

Hardware can change, too. A study titled “The way to a man’s heart is through his gut microbiota” was so named because the researchers were talking about TMAO, trimethylamine N-oxide. As you can see at 3:33 in my video, certain gut flora can take carnitine from the red meat we eat or the choline concentrated in dairy, seafood, and eggs, and convert it into a toxic compound, which may lead to an increase in our risk of heart attack, stroke, and death.

This explains why those eating more plant-based diets have lower blood concentrations of TMAO. However, they also produce less of the toxin even if you feed them a steak. You don’t see the same “conversion of dietary L-carnitine to TMAO…suggesting an adoptive response of the gut microbiota in omnivores.” They are what we feed them.

As you can see at 4:17 in my video, if you give people cyclamate, a synthetic artificial sweetener, most of their bacteria don’t know what to do with it. But, if you feed it to people for ten days and select for the few bacteria that were hip to the new synthetic chemical, eventually three quarters of the cyclamate consumed is metabolized by the bacteria into another new compound called cyclohexylamine. Stop eating it, however, and those bacteria die back. Unfortunately, cyclohexylamine may be toxic and so was banned by the FDA in 1969. In a vintage Kool-Aid ad from 1969, Pre-Sweetened Kool-Aid was taken “off your grocer’s shelves,” but Regular Kool-Aid “has no cyclamates” and “is completely safe for your entire family.”

But, if you just ate cyclamate once in a while, it wouldn’t turn into cyclohexylamine because you wouldn’t have fed and fostered the gut flora specialized to do so. The same thing happens with TMAO. Those who just eat red meat, eggs, or seafood once in a while would presumably make very little of the toxin because they hadn’t been cultivating the bacteria that produce it.


Here’s the link to my video on TMAO: Carnitine, Choline, Cancer, and Cholesterol: The TMAO Connection. For an update on TMAO, see How Our Gut Bacteria Can Use Eggs to Accelerate Cancer, Egg Industry Response to Choline and TMAO, and How to Reduce Your TMAO Levels.

Interested in more on keeping our gut bugs happy? See:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

What Explains the Egg-Cancer Connection

The reason egg consumption is associated with elevated cancer risk may be the TMAO, considered the “smoking gun” of microbiome-disease interactions.

“We are walking communities comprised not only of a Homo sapiens host, but also of trillions of symbiotic commensal microorganisms within the gut and on every other surface of our bodies.” There are more bacterial cells in our gut than there are human cells in our entire body. In fact, only about 10 percent of the DNA in our body is human. The rest is in our microbiome, the microbes with whom we share with the “walking community” we call our body. What do they do?

Our gut bacteria microbiota “serve as a filter for our largest environmental exposure—what we eat”—and, “technically speaking, food is a foreign object that we take into our bodies” by the pound every day. The “microbial community within each of us significantly influences how we experience a meal…Hence, our metabolism and absorption of food occurs through” this filter of bacteria.

However, as you can see at 1:22 in my video How Our Gut Bacteria Can Use Eggs to Accelerate Cancer, if we eat a lot of meat, including poultry and fish, milk, cheese, and eggs, we can foster the growth of bacteria that convert the choline and carnitine in those foods into trimethylamine (TMA), which can be oxidized into TMAO and wreak havoc on our arteries, increasing our risk of heart attack, stroke, and death.

We’ve known about this “troublesome” transformation from choline into trimethylamine for more than 40 years, but that was way before we learned about the heart disease connection. Why were researchers concerned back then? Because these methylamines might form nitrosamines, which have “marked carcinogenic activity”—cancer-causing activity. So where is choline found in our diet? Mostly from meat, eggs, dairy, and refined grains. The link between meat and cancer probably wouldn’t surprise anyone. In fact, just due to the industrial pollutants, like PCBs, children probably shouldn’t eat more than about five servings a month of meats like beef, pork, or chicken combined. But, what about cancer and eggs?

Studies going back to the 1970s hinted at a correlation between eggs and colon cancer, as you can see at 2:45 in my video. That was based just on so-called ecological data, though, showing that countries eating more eggs tended to have higher cancer rates, but that could be due to a million factors. It needed to be put to the test.

This testing started in the 80s, and, by the 1990s, 15 studies had been published, of which 10 suggested “a direct association” between egg consumption and colorectal cancer, “whereas five found no association.” By 2014, dozens more studies had been published, confirming that eggs may indeed be playing a role in the development of colon cancer, though no relationship was discovered between egg consumption and the development of precancerous polyps, which “suggested that egg consumption might be involved in the promotional” stage of cancer growth—accelerating cancer growth—rather than initiating the cancer in the first place.

This brings us to 2015. Perhaps it’s the TMAO made from the choline in meat and eggs that’s promoting cancer growth. Indeed, in the Women’s Health Initiative study, women with the highest TMAO levels in their blood had approximately three times greater risk of rectal cancer, suggesting that TMAO levels “may serve as a potential predictor of increased colorectal cancer risk.”

As you can see at 4:17 in my video, though there may be more evidence for elevated breast cancer risk with egg consumption than prostate cancer risk, the only other study to date on TMAO and cancer looked at prostate cancer and did indeed find a higher risk.

“Diet has long been considered a primary factor in health; however, with the microbiome revolution of the past decade, we have begun to understand how diet can” affect the back and forth between us and the rest of us inside, and the whole TMAO story is “a smoking gun” in gut bacteria-disease interactions.

Since choline and carnitine are the primary sources of TMAO production, the logical intervention strategy might be to reduce meat, dairy, and egg consumption. And, if we eat plant-based for long enough, we can actually change our gut microbial communities such that we may not be able to make TMAO even if we try.

“The theory of ‘you are what you eat’ finally is supported by scientific evidence.” We may not have to eat healthy for long, though. Soon, Big Pharma hopes, “we may yet ‘drug the microbiome’…as a way of promoting cardiovascular health.”

What did the egg industry do in response to this information? Distort the scientific record. See my video Egg Industry Response to Choline and TMAO.


This is not the first time the egg industry has been caught in the act. See, for example:

For background on TMAO see my original coverage in Carnitine, Choline, Cancer, and Cholesterol: The TMAO Connection and then find out How to Reduce Your TMAO Levels. Also, see: Flashback Friday: How to Reduce Your TMAO Levels.

This is all part of the microbiome revolution in medicine, the underappreciated role our gut flora play in our health. For more, see: 

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

How to Lower Your Sodium-to-Potassium Ratio

The potassium content in greens is one of two ways they can improve artery function within minutes of consumption.

More than a thousand years ago, for the treatment of hypertension, an ancient Persian medical text advised lifestyle interventions, such as avoiding meat and pastries, and recommended eating spinach. A thousand years later, researchers discovered that a single meal containing spinach could indeed reduce blood pressure, thanks to its nitrate content. All green leafy vegetables are packed with nitrate, which our body can use to create nitric oxide that improves the flexibility and function of our arteries. This may be why eating our greens may be one of the most powerful things we can do to reduce our chronic disease risk.

As you can see at 0:54 in my video Lowering Our Sodium-to-Potassium Ratio to Reduce Stroke Risk, just switching from low-nitrate vegetables to high-nitrate vegetables for a week can lower blood pressure by about 4 points, and the higher the blood pressure people started out with, the greater benefit they got. Four points might not sound like a lot, but even a 2-point drop in blood pressure could prevent more than 10,000 fatal strokes every year in the United States.

Potassium-rich foods may also act via a similar mechanism. If we get even just the minimum recommended daily intake of potassium, we might prevent 150,000 strokes every year. Why? Potassium appears to increase the release of nitric oxide. One week of eating two bananas and a large baked potato every day significantly improved arterial function. Even a single high-potassium meal, containing the equivalent of two to three bananas’ worth of potassium, can improve the function of our arteries, whereas a high-sodium meal—that is, a meal with the amount of salt most people eat—can impair arterial function within 30 minutes. While potassium increases nitric oxide release, sodium reduces nitric oxide release. So, the health of our arteries may be determined by our sodium-to-potassium ratio.

As you can see at 2:30 in my video, after two bacon slices’ worth of sodium, our arteries take a significant hit within 30 minutes. However, if you add three bananas’ worth of potassium, you can counteract the effects of the sodium. As I show at 2:48 in my video, when we evolved, we were eating ten times more potassium than sodium. Now, the ratio is reversed, as we consume more sodium than potassium. These kinds of studies “provide additional evidence that increases in dietary potassium should be encouraged,” but what does that mean? We should eat more beans, sweet potatoes, and leafy greens, the latter of which is like giving you a double whammy, as they are high in potassium and nitrates. The recommendation from a thousand years ago to eat spinach is pretty impressive, though bloodletting and abstaining from sex were also encouraged, so we should probably take ancient wisdom with a grain of salt—but our meals should be added-salt free.

Why might abstaining from sex not be the best idea for cardiovascular health? Because the opposite may actually be true. See my video Do Men Who Have More Sex Live Longer?.


What else can we do about stroke risk? Check out:

For more on potassium, see in Potassium and Autoimmune Disease and 98% of American Diets Potassium-Deficient.

Interested in learning more about the dangers of sodium? See:

Sodium isn’t just bad for our arteries. Check out How to Treat Asthma with a Low-Salt Diet and Sodium and Autoimmune Disease: Rubbing Salt in the Wound?.

I further explore the wonders of nitrate-rich vegetables in:

Sweet potatoes are an excellent high-potassium, low-sodium choice, but what’s the best way to prepare them? Check out The Best Way to Cook Sweet Potatoes.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

 

What Exercise Authorities Don’t Tell You About Optimal Duration

Physical fitness authorities seem to have fallen into the same trap as the nutrition authorities, recommending what they think may be achievable, rather than simply informing us of what the science says and letting us make up our own minds.

Researchers who accept grants from The Coca-Cola Company may call physical inactivity “the biggest public health problem of the 21st century,” but, in actually, physical inactivity ranks down at number five in terms of risk factors for death in the United States and even lower in terms of risk factors for disability, as you can see at 0:17 in my video How Much Should You Exercise? What’s more, inactivity barely makes the top ten globally. As we’ve learned, diet is our greatest killer by far, followed by smoking.

Of course, that doesn’t mean you can just sit on the couch all day. Exercise can help with mental health, cognitive health, sleep quality, cancer prevention, immune function, high blood pressure, and life span extension, topics I cover in some of my other videos. If the U.S. population collectively exercised enough to shave just 1 percent off the national body mass index, 2 million cases of diabetes, one and a half million cases of heart disease and stroke, and 100,000 cases of cancer might be prevented.

Ideally, how much should we exercise? The latest official “Physical Activity Guidelines for Americans” recommends adults get at least 150 minutes a week of moderate aerobic exercise, which comes out to be a little more than 20 minutes a day. That is actually down from previous recommendations from the Surgeon General, as well as from the Centers for Disease Control and Prevention (CDC) and the American College of Sports Medicine, which jointly recommend at least 30 minutes each day. The exercise authorities seem to have fallen into the same trap as the nutrition authorities, recommending what they think may be achievable, rather than simply informing us what the science says and letting us make up our own minds. They already emphasize that “some” physical activity “is better than none,” so why not stop patronizing the public and just tell everyone the truth?

As you can see at 2:16 in my video, walking 150 minutes a week is better than walking 60 minutes a week, and following the current recommendations for 150 minutes appears to reduce your overall mortality rate by 7 percent compared with being sedentary. Walking for just 60 minutes a week only drops your mortality rate about 3 percent, but walking 300 minutes weekly lowers overall mortality by 14 percent. So, walking twice as long—40 minutes a day compared with the recommended 20 daily minutes—yields twice the benefit. And, an hour-long walk each day may reduce mortality by 24 percent. I use walking as an example because it’s an exercise nearly everyone can do, but the same applies to other moderate-intensity activities, such as gardening or cycling.

A meta-analysis of physical activity dose and longevity found that the equivalent of about an hour a day of brisk walking at four miles per hour was good, but 90 minutes was even better. What about more than 90 minutes? Unfortunately, so few people exercise that much every day that there weren’t enough studies to compile a higher category. If we know 90 minutes of exercise a day is better than 60 minutes, which is better than 30 minutes, why is the recommendation only 20 minutes? I understand that only about half of Americans even make the recommended 20 daily minutes, so the authorities are just hoping to nudge people in the right direction. It’s like the Dietary Guidelines for Americans advising us to “eat less…candy.” If only they’d just give it to us straight. That’s what I try to do with NutritionFacts.org.

Most of the content in my book How Not to Die came from my video research, but this particular video actually sprung from the book. I wanted to include exercise in my Daily Dozen list, but needed to do this research to see what was the best “serving size.”

I wish someone would start some kind of FitnessFacts.org website to review the exercise literature. I’ve got my brain full with the nutrition stuff—though there’s so much good information I don’t have time to review that there could be ten more sites just covering nutritional science!


For more on all that exercise can do for our bodies and minds, see

Some tips for maximizing the benefits:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Combating Air Pollution Effects with Food

There is a food that offers the best of both worlds—significantly improving our ability to detox carcinogens like diesel fumes and decreasing inflammation in our airways—all while improving our respiratory defenses against infections.

Outdoor air pollution may be the ninth leading cause of death and disability in the world, responsible for millions of deaths from lung cancer, emphysema, heart disease, stroke, and respiratory infection. In the United States, living in a polluted city was associated with 16, 27, and 28 percent increases in total, cardiovascular, and lung cancer deaths, compared to living in a city with cleaner air. As well, living in a city with polluted air may lead to up to a 75 percent increase in the risk of a heart attack. “Additionally, the possibility of dying in a traffic jam is two and a half times greater in a polluted city.” No one wants to be living in a traffic jam, but it’s better than dying in one.

In addition to causing deaths, air pollution is also the cause of a number of health problems. It may not only exacerbate asthma but also increase the risk of developing asthma in the first place. These pollutants may trigger liver disease and even increase the risk of diabetes. Indeed, “even when atmospheric pollutants are within legally established limits, they can be harmful to health.” So, what can we do about it?

Paper after paper have described all the terrible things air pollution can do to us, but “most…failed to mention public policy. Therefore, while science is making great strides in demonstrating the harmful effects of atmospheric pollution on human health, public authorities are not using these data” to reduce emissions, as such measures might inconvenience the population “and, therefore, might not be politically acceptable.” We need better vehicle inspections, efficient public transport, bus lanes, bicycle lanes, and even urban tolls to help clean up the air, but, while we’re waiting for all of that, is there anything we can do to protect ourselves?

As I discuss in my video Best Food to Counter the Effects of Air Pollution, our body naturally has detoxifying enzymes, not only in our liver, but also lining our airways. Studies show that people born with less effective detox enzymes have an exaggerated allergic response to diesel exhaust, suggesting that these enzymes actively combat the inflammation caused by pollutants in the air. A significant part of the population has these substandard forms of the enzyme, but, either way, what can we do to boost the activity of whichever detoxification enzymes we do have?

One of my previous videos Prolonged Liver Function Enhancement from Broccoli investigated how broccoli can dramatically boost the activity of the detox enzymes in our liver, but what about our lungs? Researchers fed some smokers a large stalk of broccoli every day for ten days to see if it would affect the level of inflammation within their bodies. Why smokers? Smoking is so inflammatory that you can have elevated C-reactive protein (CRP) levels for up to 30 years after quitting, and that inflammation can start almost immediately after you start smoking, so it’s critical to never start in the first place. If you do, though, you can cut your level of that inflammation biomarker CRP nearly in half after just ten days eating a lot of broccoli. Broccoli appears to cut inflammation in nonsmokers as well, which may explain in part why eating more than two cups of broccoli, cabbage, cauliflower, kale, or other cruciferous veggies a day is associated with a 20 percent reduced risk of dying, compared to eating a third of a cup a day or less, as you can see at 3:41 in my video.

What about air pollution? We know that the cruciferous compound “is the most potent known inducer” of our detox enzymes, so most of the research has been on its ability to fight cancer. But, for the first time, researchers tried to see if it could combat the pro-inflammatory impact of pollutants, such as diesel exhaust. They put some human lung lining cells in a petri dish, and, as you can see at 4:11 in my video, the number of detox enzymes produced after dripping on some broccoli goodness skyrocketed. Yes, but we don’t inhale broccoli or snort it. We eat it. Can it still get into our lungs and help? Yes. After two days of broccoli sprout consumption, researchers took some cells out of the subjects’ noses and found up to 100 times more detox enzyme expression compared to eating a non-cruciferous vegetable, alfalfa sprouts. If only we could squirt some diesel exhaust up people’s noses. That’s just what some UCLA researchers did, at an amount equal to daily rush hour exposure on a Los Angeles freeway. Within six hours, the number of inflammatory cells in their nose shot up and continued to rise. But, in the group who had been getting a broccoli sprout extract, the inflammation went down and stayed down, as you can see at 4:58 in my video

Since the dose in those studies is equivalent to the consumption of one or two cups of broccoli, their study “demonstrates the potential preventive and therapeutic potential of broccoli or broccoli sprouts,” but if broccoli is so powerful at suppressing this inflammatory immune response, might it interfere with normal immune function? After all, the battle with viruses like influenza can happen in the nose. So what happens when some flu viruses are dripped into the nostrils of broccoli-sprout eaters compared with people consuming non-cruciferous alfalfa sprouts? After eating broccoli sprouts, we get the best of both worlds—less inflammation and an improved immune response. As you can see at 5:55 in my video, after eating alfalfa sprouts, there is a viral spike in their nose. After eating a package of broccoli sprouts every day, however, our body is able to keep the virus in check, potentially offering “a safe, low-cost strategy for reducing influenza risk among smokers and other at risk populations.”

So, better immune function, yet less inflammation, potentially reducing the impact of pollution on allergic disease and asthma, at least for an “enthusiastic broccoli consumer.” But what about cancer and detoxifying air pollutants throughout the rest of our body? We didn’t know, until now. Off to China, where “levels of outdoor air pollution…are among the highest in the world.” By day one, those getting broccoli sprouts were able to get rid of 60 percent more benzene from their bodies. “The key finding…was the observed rapid and highly durable elevation of the detoxification of… a known human carcinogen.” Now, this was using broccoli sprouts, which are highly concentrated, equivalent to about five cups of broccoli a day, so we don’t know how well more modest doses would work. But if they do, eating broccoli could “provide a frugal means to attenuate…the long-term health risks” of air pollution. More on air pollution here.

I’ve been reading about the terrible effects of air pollution for a long time and I am thrilled there’s something we can do other than uprooting our families and moving out to the countryside.


For more on cruciferocity, see my videos Lung Cancer Metastases and Broccoli and Breast Cancer Survival Vegetable.

There’s a secret to maximizing broccoli’s benefits. See Flashback Friday:Second Strategy to Cooking Broccoli.

For more on Cooking Greens: How to Cook Greens and Best Way to Cook Vegetables.

What about broccoli sprout pills? See Broccoli: Sprouts vs. Supplements.

Speaking of respiratory inflammation, what about dietary approaches to asthma? Learn more:

There are sources of indoor pollution, too. See Throw Household Products Off the Scent.

There is one way what we eat can directly impact air pollution, beyond just personal protection. Check out Flashback Friday: Diet and Climate Change: Cooking Up a Storm.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Decreasing Inflammation and Oxidation After Meals

Within hours of eating an unhealthy meal, we can get a spike in inflammation, crippling our artery function, thickening our blood, and causing a fight-or-flight nerve response. Thankfully, there are foods we can eat at every meal to counter this reaction.

Standard American meals rich in processed junk and meat and dairy lead to exaggerated spikes in sugar and fat in the blood, as you can see at 0:13 in my video How to Prevent Blood Sugar and Triglyceride Spikes after Meals. This generates free radicals, and the oxidative stress triggers a biochemical cascade throughout our circulation, damaging proteins in our body, inducing inflammation, crippling our artery function, thickening our blood, and causing a fight-or-flight nerve response. This all happens within just one to four hours after eating a meal. Worried about inflammation within your body? One lousy breakfast could double your C-reactive protein levels before it’s even lunchtime.

Repeat that three times a day, and you can set yourself up for heart disease. You may not even be aware of how bad off you are because your doctor is measuring your blood sugar and fat levels while you’re in a fasting state, typically drawing your blood before you’ve eaten. What happens after a meal may be a stronger predictor of heart attacks and strokes, which makes sense, since this is where most of us live our lives—that is, in a fed state. And it’s not just in diabetics. As you can see at 1:30 in my video, if you follow non diabetic women with heart disease but normal fasting blood sugar, how high their blood sugar spikes after chugging some sugar water appears to determine how fast their arteries continue to clog up, perhaps because the higher the blood sugars spike, the more free radicals are produced.

So, what are some dietary strategies to improve the situation? Thankfully, “improvements in diet exert profound and immediate favorable changes…,” but what kind of improvements? “Specifically, a diet high in minimally processed, high-fiber, plant-based foods such as vegetables and fruits, whole grains, legumes, and nuts,”—antioxidant, anti-inflammatory whole plant foods—“will markedly blunt the post-meal increase” in sugar, fat, and inflammation.

But what if you really wanted to eat some Wonder Bread? As you can see at 2:23 in my video, you’d get a big spike in blood sugar less than an hour after eating it. Would it make a difference if you spread the bread with almond butter? Adding about a third of a cup of almonds to the same amount of Wonder Bread significantly blunts the blood sugar spike.

In that case, would any low-carb food help? Why add almond butter when you can make a bologna sandwich? Well, first of all, plant-based foods have the antioxidants to wipe out any excess free radicals. So, nuts can not only blunt blood sugar spikes, but oxidative damage as well. What’s more, they can even blunt insulin spikes. Indeed, adding nuts to a meal calms both blood sugar levels and insulin levels, as you can see at 3:02 in my video. Now, you’re probably thinking, Well, duh, less sugar means less insulin, but that’s not what happens with low-carb animal foods.

As you can see at 3:23 in my video, if you add steamed skinless chicken breast to your white rice, you get a greater insulin spike than if you had just eaten the white rice alone. So, adding the low-carb plant food made things better, but adding the low-carb animal food made things worse. It’s the same with adding chicken breast to mashed potatoes—a higher insulin spike with the added animal protein. It is also the same with animal fat: Add some butter to a meal, and get a dramatically higher insulin spike from some sugar, as you can see at 3:45 in my video.

If you add butter and cheese to white bread, white potatoes, white spaghetti, or white rice, you can sometimes even double the insulin reaction. If you add half an avocado to a meal, however, instead of worsening, the insulin response improves, as it does with the main whole plant food source of fat: nuts.


I’ve covered the effect adding berries to a meal has on blood sugar responses in If Fructose Is Bad, What About Fruit?, and that raises the question: How Much Fruit Is Too Much?

In addition to the all-fruit jam question, I cover The Effects of Avocados and Red Wine on Postprandial Inflammation.

Vinegar may also help. See Can Vinegar Help with Blood Sugar Control?.

Perhaps this explains part of the longevity benefit to nut consumption, which I discuss in Nuts May Help Prevent Death.

I also talk about that immediate inflammatory reaction to unhealthy food choices in Best Foods to Improve Sexual Function.

Surprised by the chicken and butter reaction? The same thing happens with tuna fish and other meat, as I cover in my video Paleo Diets May Negate Benefits of Exercise.

Also check:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

 

High Blood Pressure May Lead to Low Brain Volume

Having hypertension in midlife (ages 40 through 60) is associated with elevated risk of cognitive impairment and Alzheimer’s dementia later in life, even more so than having the so-called Alzheimer’s gene.

“It is clear that cerebral vascular disease”—that is, hardening of the arteries inside our brain—“and cognitive decline travel hand in hand,” something I’ve addressed before. “However, the independent association of AD [Alzheimer’s disease] with multiple AVD [atherosclerotic vascular disease] risk factors suggests that cholesterol is not the sole culprit in dementia.”

As I discuss in my video Higher Blood Pressure May Lead to Brain Shrinkage, one of the most consistent findings is that elevated levels of blood pressure in midlife, ages 40 through 60, is associated with elevated risk of cognitive impairment and Alzheimer’s dementia later in life—in fact, even more so than having the so-called Alzheimer’s gene.

“The normal arterial tree”—all the blood vessels in the brain—“is…designed as both a conduit and cushion.” But when the artery walls become stiffened, the pressure from the pulse every time our heart pumps blood up into our brain can damage small vessels in our brain. This can cause “microbleeds” in our brain, which are frequently found in people with high blood pressure, even if they were never diagnosed with a stroke.

These microbleeds may be “one of the important factors that cause cognitive impairments,” “perhaps not surprising[ly],” because on autopsy, “microbleeds may be associated with [brain] tissue necrosis,” meaning brain tissue death.

And speaking of tissue death, high blood pressure is also associated with so-called lacunar infarcts, from the Latin word lacuna, meaning hole. These holes in our brain appear when little arteries get clogged in the brain and result in the death of a little round region of the brain. Up to a quarter of the elderly have these little mini-strokes, and most don’t even know it, so-called silent infarcts. But “no black holes in the brain are benign.” As you can see at 2:12 in my video, it’s as though your brain has been hole-punched.

“Although silent infarcts, by definition, lack clinically overt stroke-like symptoms, they are associated with subtle deficits in physical and cognitive function that commonly go unnoticed.” What’s more, they can double the risk of dementia. That’s one of the ways high blood pressure is linked to dementia.

There’s so much damage that high blood pressure levels can “lead to brain volume reduction,” literally a shrinkage of our brain, “specifically in the hippocampus,” the memory center of the brain. This helps explain how high blood pressure can be involved in the development of Alzheimer’s disease.

As you can see at 3:02 in my video, we can actually visualize the little arteries in the back of our eyes using an ophthalmoscope, providing “a noninvasive window” to study the health of our intracranial arteries, the little vessels inside our head. Researchers “found a significant association” between visualized arterial disease and brain shrinkage on MRI. However, because that was a cross-sectional study, just a snapshot in time, you can’t prove cause and effect. What’s needed is a prospective study, following people over time. And that’s just what the researchers did. Over a ten-year period, those with visual signs of arterial disease were twice as likely to suffer a significant loss of brain tissue volume over time.


What can we do about high blood pressure? A lot! See, for example:

What else can we do to forestall cognitive decline or dementia? I referenced my video Alzheimer’s and Atherosclerosis of the Brain earlier, and here are other videos that offer information on treatment and prevention:

 

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Are the BPA-Free Plastics Like Tritan Safe?

Do BPA-free plastics such as Tritan, have human hormone-disrupting effects? And what about BPS and BPF?

Recent human studies indicate that exposure to the plastics chemical BPA may be associated with infertility, miscarriage, premature delivery, reduced male sexual function, polycystic ovaries, altered thyroid and immune function, diabetes, heart disease, and more. Yet, “[a]s recently as March 2012, FDA stated that low levels of BPA in food are considered safe.” However, just months later, to its credit, the agency banned the use of BPA plastics in baby bottles and sippy cups. Regulators standing up to industry? Maybe I shouldn’t be so cynical! But, wait. The ban was at the behest of the plastics industry. It had already stopped using BPA in baby bottles so it was their idea to ban it.

The industry had switched from BPA to similar compounds like BPF and BPS. So, our diets now contain everything from BPA to BPZ, and the majority of us have these new chemicals in our bodies as well. Are they any safer?

As I discuss in my video Are the BPA-Free Alternatives Safe?, based on the similarities of their chemical structures, they are all predicted to affect testosterone production and estrogen receptor activity, as you can see at 1:40 in my video. However, they were only recently put to the test.

As you can see at 1:50 in my video, we’ve known BPA significantly suppresses testosterone production, and, from “the first report describing BPS and BPF adverse effects on physiologic function in humans,” we know those compounds do, too. Well, kind of. The experiments were performed on the testicles of aborted human fetuses. But, the bottom line is that BPS and BPF seem to have “antiandrogenic anti-male hormone effects that are similar to those of BPA.” So when you’re assured you shouldn’t worry because your sales slip is BPA-free, the thermal paper may just contain BPS instead. What’s more, BPS receipts may contain up to 40 percent more BPS than they would have contained BPA. So BPA-free could be even worse. In fact, all BPA-replacement products tested to date released “chemicals having reliably detectable EA,” estrogenic activity.

This includes Tritan, which is specifically marketed as being estrogen-activity-free. As you can see at 3:06 in my video, however, researchers dripped an extract of Tritan on human breast cancer cells in a petri dish, and it accelerated their growth. This estrogenic effect was successfully abolished by an estrogen blocker, reinforcing it was an estrogen effect. Now, the accelerated growth of the cancer cells from the Tritan extract occurred after the plastic was exposed to the stressed state of simulated sunlight. Only one out of three Tritan products showed estrogen activity in an unstressed state, for instance when they weren’t exposed to microwaving, heat, or UV rays. “Because there would be no value in trading one health hazard for another, we should urgently focus on the human health risk assessment of BPA substitutes.”

In the meanwhile, there are steps we can take to limit our exposure. We can reduce our use of polycarbonate plastics, which are usually labeled with recycle codes three or seven, and we can opt for fresh and frozen foods over canned goods, especially when it comes to tuna and condensed soups. Canned fruit consumption doesn’t seem to matter, but weekly canned vegetable consumption has been associated with increased BPA exposure. If you do use plastics, don’t microwave them, put them in the dishwasher, leave them in the sun or a hot car, or use once they’re scratched. But using glass, ceramic, or stainless steel containers is probably best.


For more on BPA, check out my videos:

Unfortunately, BPA isn’t the only plastics chemical that may have adverse health effects. See:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Pill-Free Ways to improve Your Sex Life

“Sex is important to health,” according to the Harvard Health Letter. “Frequent sexual intercourse is associated with reduced heart attack risk.” But, as I discuss in my video Do Men Who Have More Sex Live Longer?, that seems to be the perfect case of reverse causation. They’re implying that more sex leads to healthier arteries, but isn’t the opposite more likely—that is, healthier arteries lead to more sex? Blood flow in the penis is so reflective of blood flow elsewhere that penile Doppler ultrasound can predict cardiovascular disease. However, low frequency of sexual activity may predict cardiovascular disease in men independently of erectile dysfunction. This suggests that sex may be more than “just fun” and may also be therapeutic, or at least so says an editor of the Journal of Sexual Medicine and colleagues in discussing whether or not “frequent sexual activity can be prescribed” to improve general health. In men, they suggest it’s because more sex means more testosterone.

When men have sex, they get a big spike in testosterone levels in their blood, but, interestingly, in contrast, they don’t get a testosterone boost when they masturbate, as you can see at 1:21 in my video. This may be because “testosterone increases with competitive success,” like if you win a sports game. While sex “is not usually regarded as a competitive event…one’s mental state following coitus could nevertheless be something like that of a winner,” as opposed to the mental state after masturbation.

As you can see at 2:00 in my video, the spike in sex hormones in the blood is so great that men’s beards actually grow faster on days they have sex. And, since low testosterone levels are associated with increased risk of mortality, this could help explain the health benefits of having sex.

So, do men who have more sex actually live longer? I searched Pubmed for sexual activity and longevity and found a study supported by the U.S. Department of Agriculture, titled “Sexual activity and longevity of the southern green stink bug”—clearly an example of our taxpayer dollars hard at work. I was less interested in whether or not screwworms live up to their namesake and more interested in a study on sex and death, in which the objective was “to examine the relation between frequency of orgasm and mortality.” The researchers found that men with “high orgasmic frequency” appeared to cut their risk of premature death in half and, apparently, the more, the better: There was an associated 36 percent drop in mortality odds for every additional 100 orgasms a year. “Conclusion: Sexual activity seems to have a protective effect on men’s health”—but, apparently, not if you cheat. “Unfaithfulness in men seems to be associated with a higher risk of major cardiovascular events,” like heart attacks and strokes. “Extramarital sex may be hazardous and stressful because the lover is often younger…[and] a secret sexual encounter” may be more stressful.

In a large autopsy series, the majority of cases of sudden death during sex occurred in men during extramarital intercourse. The absolute risk is low—“only one out of 580 men might be expected to suffer a sudden death attributable to sexual intercourse”—but for those at high risk, research shows that “[s]ex in familiar surroundings, in a comfortable room temperature, and with the usual partner adds less stress to the heart” and may be safer.

Speaking of safe sex, you thought drinking and driving was bad? “While it is generally assumed that sexual behavior happens in parked cars, there is little discussion…in the research literature of sexual activity in moving vehicles.” About one in five college students report engaging in sex while driving, nearly half while going more than 60 miles an hour. Researchers suggest maybe this is something students should be warned about in health class.

When done right, though, love may protect your lover’s life. Given the benefits of sexual activity, “intervention programmes could also be considered, perhaps based on the exciting ‘At least five a day’ campaign aimed at increasing fruit and vegetable consumption—although the numerical imperative may have to be adjusted.”

What are some pill-free ways to improve your sex life? Exercising, quitting smoking, not drinking too much alcohol, not weighing too much, and eating a healthy diet. But what does it mean to “eat a healthy diet”? As I discuss in my video Best Foods to Improve Sexual Function, heart-healthy lifestyle changes are sex-healthy lifestyle changes, which have been demonstrated in studies from around the world, including in women (for whom there is sadly a dearth of research about in the biomedical literature). “Sexual function in women is significantly affected” by coronary artery disease, atherosclerotic narrowing of blood flow through our arteries, including the arteries that supply our pelvis. So, high cholesterol may mean “lower arousal, orgasm, lubrication, and satisfaction,” and the same holds for high blood pressure.

Given this, putting women on a more plant-based diet may help with sexual functioning.   Researchers found that improvements in female sexual function index scores were related to an increased intake of fruits, vegetables, nuts, and beans, and a shift from animal to plant sources of fat. The same for men: a significant improvement in international Index of Erectile Function scores. In fact, the largest study on diet and erectile dysfunction found that each additional daily serving of fruits or vegetables may reduce the risk of ED by 10 percent. But why? It may be due to the anti-inflammatory effects. Two years on a healthier diet resulted in a significant reduction in systemic inflammation, as indicated by reduced levels of C-reactive protein. Fiber itself may play an anti-inflammatory role. Those who eat the most fiber tend to have significantly lower levels of inflammation in their bodies, as you can see at 2:06 in my video. The opposite was found for saturated fat, “associated with an increased likelihood of elevated CRP”, C-reactive protein levels.

We’re used to seeing changes in inflammatory markers over weeks, months, or years, but people don’t realize that the level of inflammation in our bodies can change after only a single meal. For example, there’s a pro-inflammatory signaling molecule in our bodies called interleukin 18, thought to play a role in destabilizing atherosclerotic plaque. As such, the level of interleukin 18 in the blood “ is a strong predictor” of cardiovascular death.

What would happen if you fed people one of three different types of meals: sausage-egg-butter-oil sandwiches, cheeseless pizza with white flour crust, or the same cheeseless pizza but with whole-wheat crust? Within hours of eating the sausage sandwich, interleukin 18 levels shot up about 20 percent, an effect not seen after eating the plant-based pizza. In contrast, those eating the whole food, plant-based pizza made with the whole-wheat crust had about a 20 percent drop in interleukin 18 levels within hours of consumption, reinforcing dietary recommendations to eat a diet high in fiber and starches, and low in saturated fat to prevent chronic diseases.

But the billions in profits are in pills, not plants, which is why the pharmacology of the female orgasm has been studied ever since 1972 when a researcher at Tulane University implanted tubes deep within the brain of a woman so he could inject drugs directly into her brain and was able to induce repetitive orgasms. A man who had electrodes placed into similar parts of his brain was given a device for a few hours that allowed him to press the button himself to stimulate the electrode. He pressed the button up to 1,500 times.


For more on male reproductive health, see:

Also check out my other men’s health videos, such as:

What effect might that inflammation directly following an unhealthy meal have on our artery function? Check out my three-part endotoxins series starting with The Leaky Gut Theory of Why Animal Products Cause Inflammation.

And why exactly is fiber anti-inflammatory? Watch my video Prebiotics: Tending Our Inner Garden.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

What Meat and Eggs Do to Our Microbiome

As I’ve explored before, whether young or old, male or female, smoker or non-smoker, with high blood pressure or low blood pressure, high cholesterol or low, having high levels of a toxic compound called TMAO—trimethylamine oxide—in the bloodstream is associated with a significantly higher risk of having a heart attack, stroke, or dying over a three-year period. Where does TMAO come from? As I investigate in my video How to Develop a Healthy Gut Ecosystem, the choline in foods like eggs can be turned by gut bacteria into TMAO, which is then absorbed back into our system. And, the more eggs we eat, the higher the levels climb, as you can see at 0:41 in my video.

Given the similarity in structure between carnitine and choline, Cleveland Clinic researchers wondered if carnitine found in red meat, energy drinks, and supplements might also lead to TMAO production and put it to the test. As you can see at 1:00 in my video, if you feed omnivores, those who regularly eat meat, a steak, their TMAO levels shoot up. Those who eat strictly plant-based may start out with almost no TMAO in their system, presumably because they’re not eating any meat, eggs, or dairy. But, even if vegans eat a sirloin, still almost no TMAO is made. Why? Presumably, they don’t have steak-eating bacteria in their guts. Indeed, it was found that no TMAO is produced if you don’t have TMAO-producing bacteria in your gut. If you don’t regularly eat meat, then you’re not fostering the growth of the meat-eating microbes that produce TMAO.

This suggests that once we develop a plant-based gut ecosystem, our bacteria will not produce TMAO, even if we eat meat every once and awhile. However, we still don’t know how rapidly gut bacteria shift after a shift in our diet—but it does not appear to be all or nothing. If men eating the standard American diet are given two sausage, egg, and cheese biscuits before and after just five days of eating lots of similarly high-fat meals, their TMAO production boosts even higher, as you can see at 2:09 in my video. So, it’s not just whether we have the bad bugs or not. Apparently, we can breed more of them the more we feed them.

Meat-free diets, on the other hand, can also have been “demonstrated to have a profound influence on human metabolism.”Just by analyzing a urine sample, we can tell what kind of diet people eat, based on measurements like how low TMAO levels are in the urine of those eating egg-free vegetarian diets, as you can see at 2:26 in my video. At 2:43 in my video, you’ll see that we can even take the same people rotate them through three different diets, and determine who is on a high-meat diet, low-meat diet, or no-meat diet, based in part on the different compounds churned out by the different gut flora or different flora activity after just about two weeks on the different diets. It’s possible that some of the beneficial effects of whole plant foods may be mediated by the effects they have on our gut bacteria. At the same time, the standard American diet may increase the relative abundance of undesirables that produce toxic compounds including TMAO (as you can see at 3:07 in my video).

Strictly plant-based diets have gained acceptance as a dietary strategy for preventing and managing disease. Perhaps, in part, this is because of their rather unique gut flora, with less of the disease-causing bacteria and more of the protective species. So, all along, we thought the reason those eating plant-based had lower heart disease rates was because they were eating less saturated fat and cholesterol, but maybe their lower TMAO levels may also be contributing to their benefits, thanks to their reduced ingestion of carnitine and choline.

I talked about the egg industry response to the choline revelation in Egg Industry Response to Choline and TMAO. How has the carnitine supplement industry reacted? In response to the research implicating carnitine in TMAO production, the former vice president of AdvoCare—a multilevel marketing company that sells carnitine supplements like AdvoCare Slam while getting slammed with lawsuits finding them guilty of being “engaged in false, misleading or deceptive acts or practices” and forced to pay more than a million dollars—questioned whether there was a secret vegan conspiracy at the Cleveland Clinic. Restricting our intake of meat or carnitine supplements to prevent our gut bacteria from making TMAO, he argued, is like trying to prevent car accidents by restricting the sale of fuel.

Okay…but there are benefits to transportation. We’re talking about TMAO, which may be fueling our epidemic of heart disease, the number-one killer of men and women in this country. As far as I’m concerned, the more we can cut the fuel for that, the better.


For more background on TMAO, see Carnitine, Choline, Cancer, and Cholesterol: The TMAO Connection, then find out How to Reduce Your TMAO Levels.

Our gut flora are what we eat. Check out:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Using Green Tea to Help Prevent Cancer and Treat Cancer

Tea consumption is associated with a reduced risk of heart disease, stroke, and premature death in general, with each additional cup of green tea a day associated with a 4-percent lower mortality risk. So, perhaps “drinking several cups of tea daily can keep the doctor away,” as well as the mortician—but what about cancer?

As I discuss in my video Can Green Tea Help Prevent Cancer, there is “growing evidence from laboratory, epidemiologic [population], and human intervention studies that tea can exert beneficial disease-preventive effects” and, further, may actually “slow cancer progression.” Let’s review some of that evidence.

Not only do those who drink a lot of tea appear to live longer than those who drink less, as you can see at 0:49 in my video, drinking lots of tea may also delay the onset of cancer. At 0:56 in my video, you can see a table titled “Average age at cancer onset and daily green tea consumption.” The green tea intake is measured in Japanese tea cups, which only contain a half a cup, so the highest category in the table is actually greater than or equal to five full cups of tea, not ten as it appears in the table. Women who did get cancer appeared to get it seven years later if they had been drinking lots of tea compared to those who had consumed less. Men, however, had a three-year delay in cancer onset if they had consumed more than five full cups of green tea daily, the difference potentially “due to higher tobacco consumption by males.”

Green tea may be able to interfere with each of the stages of cancer formation: the initiation of the first cancer cell, promotion into a tumor, and then subsequent progression and spread, as you can see at 1:24 in my video. Cancer is often initiated when a free radical oxidizes our DNA, causing a mutation, but, as you can see at 1:44 in my video, we can get a nice “spike of antioxidant power” of our bloodstream within 40 minutes of drinking green tea. “This increase may, in turn, lower oxidative damage to DNA and so decrease risk of cancer.”

Furthermore, in terms of genoprotective effects—that is, protecting our genes—pre-existing oxidation-induced DNA damage was lower after drinking green tea, suggesting consumption can boost DNA repair as well. We didn’t know for certain, however…until now.

There is a DNA-repair enzyme in our body called OGG1. As you can see at 2:15 in my video, within one hour of drinking a single cup of green tea, we can boost OGG1’s activity, and after a week of tea drinking, we can boost it even higher. So, “regular intake of green tea has additional benefits in the prevention and/or repair of DNA damage.” In fact, tea is so DNA-protective it can be used for sperm storage for fresh samples until they can be properly refrigerated.

What’s more, tea is so anti-inflammatory it can be used for pain control as a mouthwash after wisdom tooth surgery, as you can see at 2:41 in my video. In terms of controlling cancer growth, at a dose of green tea compounds that would make it into our organs after drinking six cups of tea, it can cause cancer cells to commit suicide—apoptosis (programmed cell death)—while leaving normal cells alone. There are a number of chemotherapy agents that can kill cancer through brute force, but that can make normal cells vulnerable, too. So, “[g]reen tea appears to be potentially an ideal agent for [cancer] prevention”: little or no adverse side-effects, efficacious for multiple cancers at achievable dose levels, and able to be taken orally. We have a sense of how it works—how it stops cancer cells from growing and causing them to kill off themselves—and it’s cheap and has a history of safe, acceptable use. But, all of this was based on in-vitro studies in a test tube. “It needs to be evaluated in human trials,” concluded the researchers. Indeed, what happens when we give green tea to people with cancer? Does it help?

Tea consumption may reduce the risk of getting oral cancer. Not only may the consumption of tea boost the antioxidant power of our bloodstream within minutes and decrease the amount of free-radical DNA damage throughout our systems over time, but it can also increase the antioxidant power of our saliva and decrease the DNA damage within the inner cheek cells of smokers, though not as much as stopping smoking all together. You can see several graphs and tables showing these findings in the first 35 seconds of my video Can Green Tea Help Treat Cancer?.

Might this help precancerous oral lesions from turning into cancerous oral lesions? More than 100,000 people develop oral cancer annually worldwide, with a five-year overall survival rate of less than the flip of a coin. Oral cancer frequently arises from precancerous lesions in the mouth, each having a few percent chance of turning cancerous every year. Can green tea help?

Fifty-nine patients with precancerous oral lesions were randomized into either a tea group, in which capsules of powdered tea extract were given and their lesions were painted with green tea powder, or a control group, who essentially got sugar pills and their lesions painted with nothing but glycerin. As you can see at 1:23 in my video, within six months, lesions in 11 out of the 29 in the tea group shrunk, compared to only 3 of 30 in the placebo group. “The results indicate that tea treatment can improve the clinical manifestations of the oral lesions.”

The most important question, though, is whether the tea treatment prevented the lesions from turning cancerous. Because the trial only lasted a few months, the researchers couldn’t tell. When they scraped some cells off of the lesions, however, there was a significant drop in DNA-damaged cells within three months in the treatment groups, suggesting that things were going in the right direction, as you can see at 1:46 in my video. Ideally, we’d have a longer study to see if they ended up with less cancer and one that just used swallowed tea components, since most people don’t finger-paint with tea in their mouths. And, we got just that.

As you can see at 2:15 in my video, there were the same extraordinary clinical results with some precancerous lesions shrinking away. What’s more, the study lasted long enough to see if fewer people actually got cancer. The answer? There was just as much new cancer in the green tea group as the placebo group. So, the tea treatment resulted in a higher response rate, as the lesions looked better, but there was no improvement in cancer-free survival.

These studies were done on mostly smokers and former smokers. What about lung cancer? As you can see at 2:46 in my video, population studies suggest tea may be protective, but let’s put it to the test. Seventeen patients with advanced lung cancer were given up to the equivalent of 30 cups of green tea a day, but “[n]o objective responses were seen.” In a study of 49 cancer patients, 21 of whom had lung cancer, the subjects received between 4 and 25 cups worth of green tea compounds a day. Once again, no benefits were found. The only benefit green tea may be able to offer lung cancer patients is to help lessen the burns from the radiation treatments when applied on the skin. Indeed, green tea compresses may be able to shorten the duration of the burns, as you can see at 3:21 in my video.

The protective effects of green tea applied topically were also seen in precancerous cervical lesions, where the twice-a-day direct application of a green tea ointment showed a beneficial response in nearly three-quarters of the patients, compared to only about 10 percent in the untreated control group, which is consistent with the benefits of green tea compounds on cervical cancer cells in a petri dish. When women were given green tea extract pills to take, however, they didn’t seem to help.

I talked about the potential benefit of green tea wraps for skin cancer in Treating Gorlin Syndrome with Green Tea, but is there any other cancer where green tea can come into direct contact? Yes. Colon cancer, which grows from the inner surface of the colon that comes into contact with food and drink. As you can see at 4:13 in my video, in the colon, tea compounds are fermented by our good gut bacteria into compounds like 3,4DHPA, which appears to wipe out colon cancer cells, while leaving normal colon cells relatively intact in vitro. So one hundred thirty-six patients with a history of polyps were randomized to get green tea extract pills or not. Now, this study was done in Japan, where drinking green tea is commonplace, so, effectively, this was comparing those who drank three cups of green tea a day to subjects who drank four daily cups. A year later on colonoscopy, the added-green tea group had only half the polyp recurrence and the polyps that did grow were 25 percent smaller. With such exciting findings, why hasn’t a larger follow-up study been done? Perhaps due to the difficulty “in raising funds” for the study, “because green tea is a beverage but not a pharmaceutical.”

There is good news. Thanks to a major cancer charity in Germany, researchers are currently recruiting for the largest green tea cancer trial to date, in which more than 2,000 patients will be randomized. I look forward to presenting the results to you when they come in.


What about prostate cancer? See my videos Preventing Prostate Cancer with Green Tea and Treating Prostate Cancer with Green Tea.

You may also be interested in these somewhat older videos:

How interesting was that about wisdom teeth? Green tea can also be used as an anti-cavity mouth rinse, which I discuss in my video What’s the Best Mouthwash?.

Is Caffeinated Tea Dehydrating? Watch the video to find out.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations: