Don’t Let the Pandemic Stop Your Shots

Even as older adults await the coronavirus vaccine, many are skipping the standard ones. That’s not wise, health experts say.

Don’t Let the Pandemic Stop Your Shots

Even as older adults await the coronavirus vaccine, many are skipping the standard ones. That’s not wise, health experts say.

¿Quién recibirá primero la vacuna contra el coronavirus en Estados Unidos?

Un panel asesor de los CDC decidirá sus recomendaciones el martes por la tarde. Esto es lo que esperamos, junto con las respuestas a otras preguntas sobre la nueva vacuna.

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:

Eating Seaweed Salad May Boost Immune Function

Eating seaweed salad may boost the efficacy of vaccinations and help treat cold sores, herpes, Epstein-Barr virus, and shingles.

Billions of pounds of seaweed are harvested each year, the consumption of which “has been linked to a lower incidence of chronic diseases,” both physical and mental. For example, women who eat more seaweed during pregnancy appear to be less depressed and experience fewer seasonal allergy symptoms. There’s a problem with these cross-sectional, correlational studies, however, in that they can’t prove cause and effect. Maybe seaweed consumption is just an indicator that people generally are following “traditional Japanese dietary customs,” which have lots of different aspects that could protect against disease. To know for certain whether seaweed can modulate immune function, you have to put it to the test.

As I discuss in my video How to Boost Your Immune System with Wakame Seaweed, typically, researchers start out with in vitro studies, meaning in a test tube or a petri dish, which make for quicker, cheaper, and easier experiments. One study, for example, took eight different types of seaweed and essentially made seaweed teas to drip onto human immune system cells in a petri dish. Studies like these showed that the seaweed wakame, which is the kind you find in seaweed salad, can quadruple the replication potential of T cells, which are an important part of our immune defense against viruses like herpes simplex virus.

No one actually gave seaweed to people with herpes until a study published in 2002. Researchers gave people suffering from various herpes infections about two grams a day of pure powdered wakame, which is equivalent to about a quarter cup of seaweed salad. “All fifteen patients with active Herpetic viral infections”—including herpes virus 1, the cause of oral herpes, which causes cold sores; herpes virus 2, which causes genital herpes; herpes virus 3, which causes shingles and chicken pox; and herpes virus 4, also known as Epstein-Barr virus, which causes mono—“experienced significant lessening or disappearance of symptoms,” as you can see at 2:06 in my video. There was no control group in the study, but with no downsides to eating seaweed, why not give it a try?

Researchers also found that wakame boosted antibody production, so could it be useful to boost the efficacy of vaccines? The elderly are particularly vulnerable to suffering and dying from influenza. While the flu vaccine can help, ironically, the elderly are less likely to benefit from it because immune function tends to decline as we get older. So, researchers took 70 volunteers over the age 60. As you can see at 2:50 in my video, their baseline level of antibodies against a flu virus was about 10 GMT. What you’re looking for in a vaccination is to get a two-and-a-half-fold response, so we’d like to see that antibody level get up to at least 25 GMT to consider it an effective response. The vaccine only boosted levels to 15 to 20 GMT, though. What happened after the subjects were given some wakame extract every day for a month before the vaccination? Their levels jumped up to 30 to 35 GMT. The researchers used an extract in a pill rather than the real thing, though, so they could perform this randomized placebo-controlled study. After all, it’s kind of hard to make a convincing placebo seaweed salad.

“It is hoped that the popular seaweeds eaten daily in Japan, though almost unknown around the world outside of Japanese restaurants, will be consumed…for possible immunopotentiation”—that is, immune-boosting potential—“and for attenuating the burden of infectious diseases in the elderly.”

What else can seaweed salad do (other than taste delicious)? See my video Wakame Seaweed Salad May Lower Blood Pressure.

In general, sea vegetables are good sources of iodine, as I discuss in Iodine Supplements Before, During, and After Pregnancy, and may also be one reason Japanese women have historically had such low rates of breast cancer, which I cover in Which Seaweed Is Most Protective Against Breast Cancer?.

What else can we do to boost our immunity? Check out my videos:

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:

Boosting Antiviral Immune Function with Green Tea

Unlike most antiviral drugs, green tea appears to work by boosting the immune system to combat diseases such as genital warts (caused by HPV) and the flu (caused by the influenza virus).

According to one study, “The belief in green tea as a ‘wonder weapon’ against diseases dates back thousands of years.” I’ve talked about it in relation to chronic disease, but what about infectious disease? I explore this in my video Benefits of Green Tea for Boosting Antiviral Immune Function. Interest in the antimicrobial activity of tea dates back to a military medical journal in 1906, which suggested that servicemen fill their canteens with tea to kill off the bugs that caused typhoid fever. “However, this effect of tea was not studied further until the late 1980s” when tea compounds were pitted against viruses and bacteria in test tubes and petri dishes, but what we care about is whether it works in people. I had dismissed this entire field of inquiry as clinically irrelevant until I learned about tea’s effect on genital warts. External genital warts, caused by human wart viruses, “are one of the most common and fastest-spreading venereal diseases worldwide.”

Patients with external genital warts “present with one or several cauliflower-like growths on the genitals and/or anal regions…associated with…considerable impairment of patients’ emotional and sexual well-being.” But rub on some green tea ointment, and you can achieve complete clearance of all warts in more than 50 percent of cases.

If it works so well for wart viruses, what about flu viruses? As you can see at 1:41 in my video, it works great in a petri dish, but what about in people? Well, tea-drinking school children seem to be protected, but you don’t know about the broader population until it’s put to the test. If you give healthcare workers green tea compounds, they come down with the flu about three times less often than those given placebo, as you can see at 2:02 in my video. In fact, just gargling with green tea may help. While a similar effect was not found in high school students, gargling with green tea may drop the risk of influenza infection seven or eight-fold compared to gargling with water in elderly residents of a nursing home, where flu can get really serious.

Unlike antiviral drugs, green tea appears to work by boosting the immune system, enhancing the proliferation and activity of gamma delta T cells, a type of immune cell that acts as “a first line defense against infection.” According to the researchers, “Subjects who drank six cups of tea per day had up to a 15-fold increase in [infection-fighting] interferon gamma production in as little as one week”—but why?

There is in fact a molecular pattern shared by cancer cells, pathogens, and “edible plant products such as tea, apples, mushrooms, and wine.” So, eating healthy foods may help maintain our immune cells on ready alert, effectively priming our gamma delta T cells so they “then can provide natural resistance to microbial infections and perhaps tumors.” I guess I shouldn’t have been so surprised; tea, after all, is a “vegetable infusion.” You’re basically drinking a hot water extraction of a dark green leafy vegetable.

For more on what green tea can (and cannot) do, check out videos such as:

How else can we improve our immune function? See, for example:

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:


Vitamin D Supplements for Increasing Aging Muscle Strength

We have known for more than 400 years that muscle weakness is a common presenting symptom of vitamin D deficiency. Bones aren’t the only organs that respond to vitamin D—muscles do, too. However, as we age, our muscles lose vitamin D receptors, perhaps helping to explain the loss in muscle strength as we age. Indeed, vitamin D status does appear to predict the decline in physical performance as we get older, with lower vitamin D levels linked to poorer performance. As I discuss in my video in my video Should Vitamin D Supplements Be Taken to Prevent Falls in the Elderly?, maybe the low vitamin D doesn’t lead to weakness. Rather, maybe the weakness leads to low vitamin D. Vitamin D is the sunshine vitamin, so being too weak to run around outside could explain the correlation with lower levels. To see if it’s cause and effect, you have to put it to the test.

As you can see at 1:01 in my video, about a dozen randomized controlled trials have tested vitamin D supplements versus sugar pills. After putting them all together, we can see that older men and women taking vitamin D get significant protection from falls, especially among those who had started out with relatively low levels. This has led the conservative U.S. Preventive Services Task Force, the official prevention guideline setting body, and the American Geriatric Society to “recommend vitamin D supplementation for persons who are at high risk of falls.”

We’re not quite sure of the mechanism, though. Randomized controlled trials have found that vitamin D boosts global muscle strength, particularly in the quads, which are important for fall prevention, though vitamin D supplements have also been shown to improve balance. So, it may also be a neurological effect or even a cognitive effect. We’ve known for about 20 years that older men and women who stop walking when a conversation starts are at particularly high risk of falling. Over a six-month timeframe, few who could walk and talk at the same time would go on to fall, but 80 percent of those who stopped walking when a conversation was initiated ended up falling, as you can see at 2:14 in my video.

Other high-risk groups who should supplement with vitamin D include those who have already fallen once, are unsteady, or are on a variety of heart, brain, and blood pressure drugs that can increase fall risk. There’s also a test called “Get-Up-and-Go,” which anyone can do at home. Time how long it takes you “to get up from an armchair, walk 10 feet, turn around, walk back, and sit down.” If it takes you longer than ten seconds, you may be at high risk.

So, how much vitamin D should you take? As you can see at 3:00 in my video, it seems we should take at least 700 to 1,000 units a day. The American Geriatric Society (AGS) recommends a total of 4,000 IU a day, though, based on the rationale that this should get about 90 percent of people up to the target vitamin D blood level of 75 nanomoles per liter. Although 1,000 IU should be enough for the majority of people, 51 percent, the AGS recommends 4,000 IU to capture 92 percent of the population. That way, you don’t have to routinely test levels, since 4,000 IU will get most people up to the target level and “is considerably below the proposed upper tolerable intake of 10,000 IU/d.” The AGS does not recommend periodic mega-doses.

Despite the AGS’s recommendation, because it’s hard to get patients to comply with pills, why not just give people one megadose, like 500,000 units, once a year, perhaps when they come in for their flu shot? That way, every year, you can at least guarantee an annual spike in vitamin D levels that lasts a few months, as you can see at 4:00 in my video. It’s unnatural but certainly convenient, for the doctor at least. The problem is that it actually increases fall risk, a 30 percent increase in falls in those first three months of the spike. Similar results were found in other mega-dose trials. It may be a matter of too much of a good thing. See, “vitamin D may improve physical performance, reduce chronic pain, and improve mood” so much that people start moving around more and, thereby, increase fall risk. When you give people a whopping dose of vitamin D, they get a burst in physical, mental, and social functioning, and it may take time for their motor control to catch up to their improved muscle function. It would be like giving someone a sports car when they’ve been used to driving a beater. You’ve got to take it slow.

It’s possible, too, that such unnaturally high doses may actually damage the muscles. The evidence the researchers cite in support is a meat industry study showing you can improve the tenderness of steaks by feeding cattle a few million units of vitamin D. The concern is that such high doses may be over-tenderizing our own muscles, as well. Higher vitamin D levels are associated with a progressive drop in fracture risk, but too much vitamin D may be harmful, as you can see at 5:29 in my video.

The bottom line is that vitamin D supplementation appears to help, but the strongest and most consistent evidence for prevention of serious falls is exercise. If you compare the two, taking vitamin D may lower your fall risk compared to placebo, but strength and balance training with or without vitamin D may be even more powerful, as you can see at 5:41 in my video.

Other studies in which vitamin D supplements have been put to the test in randomized placebo-controlled studies, effectively proving—or disproving—their efficacy, are featured in videos such as:

That brings up a number of important questions, which I answer in these videos:

Unfortunately, most supplements are useless—or worse. Here are some additional videos on supplements I’ve produced that may be of interest to you:

For more on the benefits of exercise, see Longer Life Within Walking Distance and How Much Should You Exercise?

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: