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:

Where Does the Arsenic in Rice, Mushrooms, and Wine Come From?

What happens when our crops are grown in soil contaminated with arsenic-based pesticides and arsenic drug-laced chicken manure?

When arsenic-containing drugs are fed to chickens, not only does the arsenic grow out into their feathers, which are then fed back to them as a slaughterhouse byproduct, but the arsenic can also get into their tissues and then into our tissues when we eat eggs or meat, a cycle depicted at the start of my video Where Does the Arsenic in Rice, Mushrooms, and Wine Come From?. This explains why national studies have found that those who eat more poultry have tended to have more arsenic flowing through their bodies. Why would the industry do that? In modern poultry farms, often called CAFOs for concentrated animal feeding operations, there can be 200,000 birds under one roof and the floors of these buildings become covered with feces. While this so-called factory farming decreases costs, it also increases the risk of disease. That’s where arsenic-containing drugs and other antibiotic feed additives can come in: to try to cut down the spread of disease in such an unnatural environment. If you’re feeling a little smug because you don’t eat chicken, what do you think happens to the poop?

As depicted at 1:17 in my video, from chicken manure, the arsenic from the drugs in the animal feed can get into our crops, into the air, and into the groundwater, and find its way into our bodies whether we eat meat or not. Yes, but how much arsenic are we really talking about? Well, we raise billions of chickens a year, and, if, historically, the vast majority were fed arsenic, then, if you do the math, we’re talking about dumping a half million pounds of arsenic into the environment every year—much of it onto our crops or shoveled directly into the mouths of other farm animals.

Most of the arsenic in chicken waste is water soluble, so, there are certainly concerns about it seeping into the groundwater. But, if it’s used as a fertilizer, what about our food? Studies on the levels of arsenic in the U.S. food supply dating back to the 1970s identified two foods, fish aside, with the highest levels—chicken and rice—both of which can accumulate arsenic in the same way. Deliver an arsenic-containing drug like roxarsone to chickens, and it ends up in their manure, which ends up in the soil, which ends up in our pilaf. “Rice is [now] the primary source of As [arsenic] exposure in a non seafood diet.”

I was surprised to learn that mushrooms are in the top-five food sources of arsenic, but then it made sense after I found out that poultry litter is commonly used as a starting material to grow mushrooms in the United States. As you can see at 2:58 in my video, over the years, the arsenic content in mushrooms has rivaled arsenic concentration in rice, though people tend to eat more rice than mushrooms on a daily basis. Arsenic levels in mushrooms seemed to be dipping starting about a decade ago, which was confirmed in a 2016 paper that looked at a dozen different types of mushrooms: plain white button mushrooms, cremini, portobello, shiitake, trumpet, oyster, nameko, maitake, alba clamshell, brown clamshell, and chanterelle. Now, mushrooms are only averaging about half the arsenic content as rice, as you can see at 3:37 in my video.

Just like some mushrooms have less arsenic than others, some rice has less. Rice grown in California has 40 percent less arsenic than rice grown in Arkansas, Louisiana, Mississippi, Missouri, and Texas. Why? Well, arsenic-based pesticides had been used for more than a century on millions of acres of cotton fields, a practice noted to be “dangerous” back in 1927. Arsenic pesticides are now effectively banned, so it’s not simply a matter of buying organic versus conventional rice because millions of pounds of arsenic had been laid down in the soil well before the rice was even planted.

The rice industry is well aware of this. There’s an arsenic-toxicity disorder in rice called “straighthead,” where rice planted in soil too heavily contaminated with arsenic doesn’t grow right. So, instead of choosing cleaner cropland, they just developed arsenic-resistant strains of rice. Now, lots of arsenic can build up in rice without the plant getting hurt. Can the same be said, however, for the rice consumer?

It’s the same story with wine. Arsenic pesticides were used, decade after decade, and even though they’ve since been banned, arsenic can still be sucked up from the soil, leading to “the pervasive presence of arsenic in [American] wine [that] can pose a potential health risk.” Curiously, the researchers sum up their article by saying that “chronic arsenic exposure is known to lower IQ in children,” but if kids are drinking that much wine, arsenic toxicity is probably the least of their worries.

Hold on. Chickens are being fed arsenic-based drugs? See Where Does the Arsenic in Chicken Come From? to find out more.


 I expect the arsenic-in-rice issue brought up a lot of questions, and giving you answers is exactly why I’m here! 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:

Why Was Chicken the Primary Source of Arsenic Exposure in Children?

What was the National Chicken Council’s response to public health authorities calling for the industry to stop feeding arsenic-based drugs to poultry?

“Dietary practices influence our exposure to pesticides, toxic heavy metals, persistent organic pollutants, and industrial pollutants….A diet high in fish and other animal products, for example, results in greater exposure to persistent organic compounds and metals than does a plant-based diet because these compounds bioaccumulate up the food chain.” Researchers at UC Davis analyzed the diets of children and adults in California to see just how bad things have gotten.

Cancer benchmark levels were exceeded by all children—100 percent of children—for arsenic, the banned pesticides dieldrin and DDT, metabolite DDE, as well as dioxins, and not just by a little. As you can see at 0:51 in my video Where Does the Arsenic in Chicken Come From?, researchers found more than a hundred times the acceptable daily exposure for arsenic in preschoolers, school-aged children, parents, and older adults, about ten times the acceptable levels for various pesticides, and up to a thousand times the daily dose for dioxins. Where are all these toxins coming from?

The number-one source of dioxins in the diets of Californian preschoolers, kids, parents, and grandparents appears to be dairy for all age groups, followed by meat, and then white potatoes, refined grains, mushrooms, poultry, and fish.

These days, our DDT legacy is also mostly from dairy. Dieldrin was created as a safer alternative to DDT, but it was banned just two years later, in 1974, though it’s still found in our bodies, mostly thanks to dairy, meat, and, evidently, cucumbers.

Chlordane made it into the 1980s before being banned, though we’re still exposed through dairy (and cukes). Lead is — foodwise — also mostly from dairy, and mercury is not surprisingly mostly from tuna and other seafood. But the primary source of arsenic in children? Surprisingly, mostly from chicken. Why?

Let me tell you a tale of arsenic in chicken. Arsenic is “well known as a poison by anyone who reads mysteries or the history of the Borgias, and with its long and colourful history, arsenic is not something that people want in their food.” So, when a biostatistics student went to the USDA in 2000 in search of a project for his master’s degree, he decided to look into it. He found a startling difference: Arsenic levels in chicken were three times higher than in other meats. His veterinary colleagues weren’t at all surprised and explained that four different types of arsenic-containing antibiotic drugs are fed to poultry—and have been fed to them since 1944.

“While arsenic-based drugs had been fed to poultry since the 1940s, recognition of this source of exposure [for humans] only occurred after appropriate statistical analysis of the data”—that is, after this student churned through the data. It was published in 2004 and expanded upon in 2006. The National Chicken Council (NCC) was none too pleased, saying lots of foods are contaminated with arsenic. “By focusing specifically on chicken, IATP [the Institute for Agriculture and Trade Policy] makes it clear that it is producing a publicity-oriented document focused on the objective of forcing [chicken] producers to stop using these safe and effective products”—by which the NCC means these arsenic-containing drugs. In fact, the NCC admits to using them but says we don’t need to worry because chicken producers use organic arsenic, “not the inorganic form made infamous in ‘Arsenic and Old Lace.’” Okay, so we don’t need to worry—until, apparently, we cook it. When chicken is cooked, it appears that some of the arsenic drug in the meat turns into the ”Arsenic and Old Lace” variety. So, the Poison-Free Poultry Act of 2009 was introduced into Congress, flopped, and was followed by the subsequent introduction of the Poison-Free Poultry Act of 2011. Did the second attempt fare any better? No, legislators once again said pish posh to poison-poor poultry. So, in 2013, a coalition of nine organizations got together and sued the FDA, and by December 31, 2015, all arsenic-containing poultry drugs were withdrawn. As of 2016, arsenic is no longer to be fed to chickens. The bad news is that without giving birds the arsenic-containing drug roxarsone, chicken may lose some of its “appealing pink color.”

In the end, the poultry industry got away with exposing the American public to arsenic for 72 years. “It should be noted that the European Union has never approved drugs containing arsenic for animal consumption” in the first place, saying, Hmm, feed our animals arsenic? No thanks, nein danke, no grazie, non, merci.

Europe has also long since banned the “urgent threat to human health” posed by feeding farm animals millions of pounds of human antibiotics. As you can see at 5:30 in my video, feeding chickens en masse literally tons of drugs like tetracyclines and penicillins to fatten them faster is a problem that gets worse every year instead of better and dates back to 1951 when drug companies whipped out the ALL CAPS in advertisements,  promising “PROFITS…several times higher!”, a dangerous practice the poultry industry has gotten away with for 68 years…and counting.


If you don’t eat poultry and are feeling a little cocky, you may want to check out my 12-video series on arsenic in rice before you gloat too much:

Think feeding arsenic to chickens is weird? Check out Illegal Drugs in Chicken Feathers.

And for more on the critical public health threat posed by antibiotic overuse in animal agriculture, 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:

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:

Fermented or Unfermented Soy?

As you can see at the start of my video Fermented or Unfermented Soy Foods for Prostate Cancer Prevention?, there is an enormous variation in the rates of prostate cancer around the globe, with among the highest rates in the United States and lowest rates in Asia—though that may be changing. The largest increase in prostate cancer rates in the world in recent decades has been in South Korea, for example: a 13-fold increase in prostate cancer deaths nationwide. Researchers suggested the increase in animal foods may have played a role, since that was the biggest change in their diet over that period, with nearly an 850 percent increase.

This is consistent with what we know in general about foods and the prevention and management of prostate cancer. Tomatoes, cruciferous vegetables like broccoli, and soy foods appear to decrease risk, there’s no clear benefit from fish, but there is an increased risk associated with meat and dairy, as you can see at 0:52 in my video. This may be because a diet based around whole plant foods “may effectively reduce inflammation in the body.”

There is also a genetic factor. If you have a first-degree relative with prostate cancer, you may be at three-fold higher risk, but non-genetic factors may increase your risk 300-fold. How do we know the low rates in Asia aren’t genetic? Because when Asians move to the United States, their rates shoot up, “and by the second generation, the incidence rate [is] already approaching that of average Americans.” This may be because of more Burger Kings and Dairy Queens, but could also be because of eating fewer protective foods, such as soy.

A systematic review of all soy and prostate cancer population studies to date confirmed that soy foods are associated with lower the risk, but that’s a relatively broad category. There are all sorts of soy foods. There are fermented soy foods, like miso and tempeh, and unfermented ones, like tofu and soy milk. Which are more protective? Researchers sifted through the studies, and it turns out that only the unfermented soy seemed to help. Tofu and soy milk consumption was associated with about a 30 percent reduction in risk, whereas there didn’t appear to be any protection linked to fermented soy foods.


What about other healthy plant foods, like broccoli and turmeric? See what they can do in Best Supplements for Prostate Cancer.

Dean Ornish and his colleagues got amazing results, apparently reversing the progression of prostate cancer with a plant-based diet and lifestyle program. Do you think it could be because of the soy? It wasn’t just a vegan diet, but a vegan diet supplemented with a daily serving of tofu and a soy protein isolate powder. Find out in The Role of Soy Foods in Prostate Cancer Prevention and Treatment.

More on the number-one cancer among men:

What about soy and breast cancer? I’m glad you asked!

Who Shouldn’t Eat Soy? 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:

Garlic Powder to Lower Lead Levels

There are so-called chelation drugs that can be taken for acute, life-threatening lead poisoning—for instance if your two-year-old swallowed one of the little lead weights her grandma was using while sewing curtains and the doctor happened to miss it on x-ray, so it stayed lodged inside her until she died with a blood lead level of 283 mcg/dcl, a case I discuss in my video Best Foods for Lead Poisoning: Chlorella, Cilantro, Tomatoes, Moringa?.

However, for lower grade, chronic lead poisoning, such as at levels under 45 μg/dL, there were no clear guidance as to whether these chelation drugs were effective. When they were put to the test, the drugs failed to bring down lead levels long term. Even when they worked initially, in dose after dose, the lead apparently continued to seep from the patients’ bones, and, by the end of the year, they ended up with the same lead levels as the sugar pill placebo group, as you can see at 0:50 in my video. It was no surprise, then, that even though blood lead levels dipped at the beginning, researchers found no improvements in cognitive function or development.

Since much of lead poisoning is preventable and the drugs don’t seem to work in most cases, that just underscores the need “to protect children from exposure to lead in the first place.” Despite the medical profession’s “best intentions to do something to help these kids…drug therapy is not the answer.” Yes, we need to redouble efforts to prevent lead poisoning in the first place, but what can we do for the kids who’ve already been exposed?

The currently approved method, these chelating drugs that bind and remove lead from our tissues, “lack[s]…safety and efficacy when conventional chelating agents are used.” So, what about dietary approaches? Plants produce phytochelatins. All higher plants possess the capacity to synthesize compounds that bind up heavy metals to protect themselves from the harmful effects, so what if we ate the plants? “Unlike other forms of treatment (e.g., pharmacotherapy with drugs), nutritional strategies carry the promise of a natural form of therapy that would presumably be cheap and with few to no side effects.” Yes, but would it work when the drugs didn’t?

We had learned that a meal could considerably cut down on lead absorption, but “the particular components of food intake that so dramatically reduce lead absorption” were uncertain at the time. Although the calcium content of the meal appeared to be part of it, milk didn’t seem to help and even made things worse. What about calcium supplements? Some assert that calcium supplements may help in reducing lead absorption in children, but “recommendations…must be based on evidence rather than conviction.” What’s more, those assertions are based in part on studies on rodents, and differences in calcium absorption and balance between rats and humans make extrapolation tricky. What you have to do is put it to the test. Researchers found that even an extra whopping 1,800 mg of calcium per day had no effect on blood lead levels. Therefore, the evidence doesn’t support conclusions that calcium supplements help.

What about whole foods? Reviews of dietary strategies to treat lead toxicity say to eat lots of tomatoes, berries, onions, garlic, and grapes, as they are natural antagonists to lead toxicity and therefore should be consumed on a regular basis. Remember those phytochelatins? Perhaps eating plants might help detoxify the lead in our own bodies or the bodies of those we eat.

These natural phytochelatin compounds work so well that we can use them to clean up pollution. For example, the green algae chlorella can suck up lead and hold onto it, so what if we ate it? If it can clean up polluted bodies of water, might it clean up our own polluted bodies? We don’t know, because we only have studies on mice, not men and women.

So, when you hear how chlorella detoxifies, they’re talking about the detoxification of rat testicles. Yes, a little sprinkle of chlorella might help your pet rat, or perhaps you could give them some black cumin seeds or give them a sprig of cilantro, but when you hear how cilantro detoxifies against heavy metals, I presume you don’t expect the researchers to be talking about studies in rodents. If we’re interested in science protecting our children, not just their pets, we’re out of luck.

The same is true with moringa, tomatoes, flaxseed oil, and sesame seed oil, as well as black grapes, and black, white, green, and red tea. There are simply no human studies to guide us.

Dietary strategies for the treatment of lead toxicity are often based on rodent studies, but, for tofu, at least, there was a population study of people that showed lower lead levels in men and women who ate more tofu. The researchers controlled for a whole bunch of factors, so it’s not as if tofu lovers were protected just because they smoked less or ate less meat, but you can’t control for everything.

Ideally, we’d have a randomized, placebo-controlled study. Researchers would take a group of people exposed to lead, split them into two groups, with half given food and the other half given some kind of identical placebo food, and see what happens. It’s easy to do this with drugs because you just use look-alike sugar pills as placebos so people don’t know which group they’re in, but how do you make placebo food? One way to do disguised food interventions is to use foods that are so potent they can be stuffed into a pill—like garlic. There had been various studies measuring the effects of garlic in rats and looking at garlic as a potential antidote for lead intoxication distributed among different mouse organs, but who eats mouse organs? One animal study did have some direct human relevance, though, looking at the effect of garlic on lead content in chicken tissues. The purpose was to “explore the possible use of garlic to clean up lead contents in chickens which”—like all of us on planet Earth—“had been exposed to lead pollution and consequently help to minimize the hazard” of lead-polluted chicken meat.

And…it worked! As you can see at 1:59 in my video Best Food for Lead Poisoning: Garlic, feeding garlic to chickens reduced lead levels in the “edible mass of chicken” by up to 75 percent or more. Because we live in a polluted world, even if you don’t give the chickens lead and raise them on distilled water, they still end up with some lead in their meat and giblets. But, if you actively feed them lead for a week, the levels get really high. When you give them the same amount of lead with a little garlic added, however, much less lead accumulates in their bodies.

What’s even more astonishing is that when researchers gave them the same amount of lead—but this time waited a week before giving them the garlic—it worked even better. “The value of garlic in reducing lead concentrations…was more pronounced when garlic was given as a post-treatment following the cessation of lead administration”—that is, after the lead was stopped and had already built up in their tissues. We used to think that “the beneficial effect of garlic against lead toxicity was primarily due to a reaction between lead and sulfur compounds in garlic” that would glom on to lead in the intestinal tract and flush it out of the body. But, what the study showed is that garlic appears to contain compounds that can actually pull lead not only out of the intestinal contents, but also out of the tissues of the body. So, the “results indicate that garlic contain chelating compounds capable of enhancing elimination of lead,” and “garlic feeding can be exploited to safeguard human consumers by minimizing lead concentrations in meat….”

If garlic is so effective at pulling lead out of chickens’ bodies, why not more directly exploit “garlic feeding” by eating it ourselves? Well, there had never been a study on the ability of garlic to help lead-exposed humans until…2012? (Actually, I’m embarrassed to say I missed it when the study was first published. That was back when I was just getting NutritionFacts.org up and running. Now that we have staff and a whole research team, hopefully important studies like this won’t slip through the cracks in the future.)

The study was a head-to-head comparison of the therapeutic effects of garlic versus a chelation therapy drug called D-penicillamine. One hundred and seventeen workers exposed to lead in the car battery industry were randomly assigned into one of two groups and, three times a day for one month, either got the drug or an eighth of a teaspoon of garlic powder compressed into a tablet, which is about the equivalent of two cloves of fresh garlic a day. As expected, the chelation drug reduced blood lead levels by about 20 percent—but so did the garlic. The garlic worked just as well as the drug and, of course, had fewer side effects. “Thus, garlic seems safer clinically and as effective,” but saying something is as effective as chelation therapy isn’t saying much. Remember how chelation drugs can lower blood levels in chronic lead poisoning, but they don’t actually improve neurological function?

Well, after treatment with garlic, significant clinical improvements were seen, including less irritability, fewer headaches, and improvements in reflexes and blood pressure, but these improvements were not seen in the drug group. They weren’t seen after treatment with the chelation therapy drug. So, garlic was safer and more effective. “Therefore, garlic can be recommended for the treatment of mild-to-moderate lead poisoning.


 There are also some human studieson vitamin C. Check out Can Vitamin C Help with Lead Poisoning?.

For even more lead videos, see:

To learn more about chlorella, 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:

What Happens if You Have Red Wine or Avocados with a Meal?

Whole plant sources of sugar and fat can ameliorate some of the postprandial (after meal) inflammation caused by the consumption of refined carbohydrates and meat.

Studies have shown how adding even steamed skinless chicken breast can exacerbate the insulin spike from white rice, but fish may be worse. At 0:18 in my video The Effects of Avocados and Red Wine on Meal-Induced Inflammation, you can see how the insulin scores of a low-carbohydrate plant food, peanuts, is lower compared to common low-carb animal foods—eggs, cheese, and beef. Fish was even worse, with an insulin score closer to doughnut territory.

At 0:36 in my video, you can see the insulin spike when people are fed mashed white potatoes. What do you think happens when they’re also given tuna fish? Twice the insulin spike. The same is seen with white flour spaghetti versus white flour spaghetti with meat. The addition of animal protein may make the pancreas work twice as hard.

You can do it with straight sugar water, too. If you perform a glucose challenge to test for diabetes, drinking a certain amount of sugar, at 1:10 in my video, you can see the kind of spike in insulin you get. But, if you take in the exact same amount of sugar but with some meat added, you get a higher spike. And, as you can see at 1:25 in my video, the more meat you add, the worse it gets. Just adding a little meat to carbs doesn’t seem to do much, but once you get up to around a third of a chicken’s breast worth, you can elicit a significantly increased surge of insulin.

So, a chicken sandwich may aggravate the metabolic harm of the refined carb white bread it’s on, but what about a PB&J? At 1:49 in my video, you can see that adding nuts to Wonder Bread actually calms the insulin and blood sugar response. What if, instead of nuts, you smeared on an all fruit strawberry jam? Berries, which have even more antioxidants than nuts, can squelch the oxidation of cholesterol in response to a typical American breakfast and even reduce the amount of fat in your blood after the meal. And, with less oxidation, there is less inflammation when berries are added to a meal.

So, a whole plant food source of sugar can decrease inflammation in response to an “inflammatory stressor” meal, but what about a whole plant food source of fat? As you can see at 2:38 in my video, within hours of eating a burger topped with half an avocado, the level of an inflammatory biomarker goes up in your blood, but not as high as eating the burger without the avocado. This may be because all whole plant foods contain antioxidants, which decrease inflammation, and also contain fiber, which is one reason even high fat whole plant foods like nuts can lower cholesterol. And, the same could be said for avocados. At 3:12 in my video, you can see avocado causing a significant drop in cholesterol levels, especially in those with high cholesterol, with even a drop in triglycerides.

If eating berries with a meal decreases inflammation, what about drinking berries? Sipping wine with your white bread significantly blunts the blood sugar spike from the bread, but the alcohol increases the fat in the blood by about the same amount. As you can see at 3:40 in my video, you’ll get a triglycerides bump when you eat some cheese and crackers, but if you sip some wine with the same snack, triglycerides shoot through the roof. How do we know it was the alcohol? Because if you use dealcoholized red wine, the same wine but with the alcohol removed, you don’t get the same reaction. This has been shown in about a half dozen other studies, along with an increase in inflammatory markers. So, the dealcoholized red wine helps in some ways but not others.

A similar paradoxical effect was found with exercise. If people cycle at high intensity for about an hour a half-day before drinking a milkshake, the triglycerides response is less than without the prior exercise, yet the inflammatory response to the meal appeared worse, as you can see at 4:18 in my video. The bottom line is not to avoid exercise but to avoid milkshakes.

The healthiest approach is a whole food, plant-based diet, but there are “promising pharmacologic approaches to the normalization” of high blood sugars and fat by taking medications. “However, resorting to drug therapy for an epidemic caused by a maladaptive diet is less rational than simply realigning our eating habits with our physiological needs.”

Protein from meat can cause more of an insulin spike than pure table sugar. See the comparisons in my video Paleo Diets May Negate Benefits of Exercise.

Interested in more information on the almond butter study I mentioned? I discuss it further in How to Prevent Blood Sugar and Triglyceride Spikes After Meals.

Berries have their own sugar, so how can eating berries lower the blood sugar spike after a meal? Find out in If Fructose Is Bad, What About Fruit?


For more on avocados, check out:

And here are more videos on red wine:

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 Sodium in Miso?

According to the second World Cancer Research Fund/American Institute for Cancer Research expert report, “[s]alt is a probable cause of stomach cancer,” one of the world’s leading cancer killers. If the report’s estimate of an 8 percent increase in risk for every extra gram of salt a day is correct, then in a country like the United Kingdom, nearly 1,700 cases of stomach cancer happen every year just because of excess salt intake, as you can see at 0:27 in my video Is Miso Healthy?, and, in a country like the United States, it would be thousands more annually.

The risk of stomach cancer associated with salt intake appears on par with smoking or heavy alcohol use, but may only be half as bad as opium use or increased total meat consumption, as you can see at 0:43 in my video. These findings were based on a study of more than a half million people, which may explain why those eating meatless diets appear to have nearly two-thirds lower risk.

We know dietary salt intake is directly associated with the risk of stomach cancer, and the higher the intake, the higher the risk. A meta-analysis went one step further and looked at specific salt-rich foods: pickled foods, salted fish, processed meat, and miso soup. Habitual consumption of pickled foods, salted fish, and processed meat were each associated with about a 25 percent greater risk of stomach cancer. The pickled foods may explain why Korea, where the pickled cabbage dish kimchi is a staple, appears to have the highest stomach cancer rates in the world, as you can see at 1:39 in my video. But researchers found there was no significant association with the consumption of miso soup. This may be because the carcinogenic effects of the salt in miso soup are counteracted by the anti-carcinogenic effects of the soy, effectively canceling out the risk. And, if we made garlicky soup with some scallions thrown in, our cancer risk may drop even lower, as you can see at 2:06 in my video.

Cancer isn’t the primary reason people are told to avoid salt, though. What about miso soup and high blood pressure? Similar to the relationship between miso and cancer, the salt in miso pushes up our blood pressures, but miso’s soy protein may be relaxing them down. If we compare the effects of soy milk to cow’s milk, for example, and, to make it even more fair, compare soy milk to skim cow’s milk to avoid the saturated butter fat, soy milk can much more dramatically improve blood pressure among women with hypertension, as you can see at 2:43 in my video. But would the effect be dramatic enough to counter all the salt in miso? Japanese researchers decided to put it to the test.

For four years, they followed men and women in their 60s, who, at the start of the study, had normal blood pressure, to see who was more likely to be diagnosed with hypertension in that time: those who had two or more bowls of miso soup a day or those who had one or less. Two bowls a day may add a half teaspoon of salt to one’s daily diet, yet those who had two or more bowls of miso soup every day appeared to have five times lower risk of becoming hypertensive. So, maybe the anti-hypertensive effects of the soy in the miso exceed the hypertensive effects of the salt.


Indeed, miso paste, a whole soy food, can be used as a “green light” source of saltiness when cooking. That’s why I used it in my pesto recipe in How Not to Die and in my How Not to Die Cookbook. It can help you in Shaking the Salt Habit.

Not convinced that salt is bad for you? Check out these videos:

Not convinced that soy is good for you? 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: