Vegans Should Consider Taking DHA Supplements

We are all fatheads.

Indeed, about half the dry weight of our brain is fat. Lower levels of the long-chain omega-3 fat DHA in some areas of Alzheimer’s brains got people thinking that perhaps DHA is protective. Since the level of DHA in the brain tends to correlate with the level of DHA in the blood, cross-sectional studies of dementia and pre-dementia patients have been done. The result? The dementia and pre-dementia subjects do tend to have lower levels of both long-chain omega-3s, EPA and DHA, circulating in their bloodstream. This doesn’t necessarily mean that lower omega-3 levels cause cognitive impairment, however. It was just a snapshot in time, so we don’t know which came first. As I discuss in my video Should Vegans Take DHA to Preserve Brain Function?, maybe the dementia led to a dietary deficiency, rather than a dietary deficiency leading to dementia.

What we need is to measure long-chain omega-3 levels at the beginning and then follow people over time, and, indeed, there may be a slower rate of cognitive decline in those who start out with higher levels. We can actually see the difference on MRI. Thousands of older men and women had their levels checked and were scanned and then re-scanned. The brains of those with higher levels looked noticeably healthier five years later.

The size of our brain actually shrinks as we get older, starting around age 20. Between ages 16 and 80, our brain loses about 1 percent of its volume every two to three years, such that by the time we’re in our 70s, our brain has lost 26 percent of its size and ends up smaller than that of 2- to 3-year-old children.

As we age, our ability to make long-chain omega-3s like DHA from short-chain omega-3s in plant foods, such as flaxseeds, chia seeds, walnuts, and greens, may decline. Researchers compared DHA levels to brain volumes in the famed Framingham Study and found that lower DHA levels were associated with smaller brain volumes, but this was just from a snapshot in time, so more information was needed. A subsequent study was published that found that higher EPA and DHA levels correlated with larger brain volume eight years later. While normal aging results in overall brain shrinkage, having lower levels of long-chain omega-3s may signal increased risk. The only thing we’d now need to prove cause and effect is a randomized controlled trial showing we can actually slow brain loss by giving people extra long-chain omega-3s, but the trials to date showed no cognitive benefits from supplementation…until now.

A “double-blind randomized interventional study provide[d] first-time evidence that [extra long-chain omega-3s] exert positive effects on brain functions in healthy older adults,” a significant improvement in executive function after six and a half months of supplementation, and significantly less brain shrinkage compared to placebo. This kind of gray matter shrinkage in the placebo might be considered just normal brain aging, but it was significantly slowed in the supplementation group. The researchers also described changes in the white matter of the brain, increased fractional anisotropy, and decreases in mean and radial diffusivity—terms I’ve never heard before but evidently imply greater structural integrity.

So, we know that having sufficient long-chain omega-3s EPA and DHA may be important for preserving brain function and structure, but what’s “sufficient” and how do we get there? The Framingham Study found what appears to be a threshold value around an omega-3 index of 4.4, which is a measure of our EPA and DHA levels. Having more or much more than 4.4 didn’t seem to matter, but having less was associated with accelerated brain loss equivalent to about an extra two years of brain aging, which comes out to about a teaspoon less of brain matter, so it’s probably good to have an omega-3 index over 4.4.

The problem is that people who don’t eat fish may be under 4.4. Nearly two-thirds of vegans may fall below 4.0, suggesting a substantial number of vegans have an omega-3 status associated with accelerated brain aging. The average American just exceeds the threshold at about 4.5, though if we age- and gender-match with the vegans, ironically, the omnivores do just as bad. There aren’t a lot of long-chain omega-3s in Big Macs either, but having a nutrient status no worse than those eating the Standard American Diet is not saying much.

What we need is a study that gives those with such low levels some pollutant-free EPA and DHA, and then sees how much it takes to push people past the threshold…and here we go: Phase 2 of the study gave algae-derived EPA and DHA to those eating vegan diets with levels under 4.0. About 250mg a day took them from an average of 3.1 over the threshold to 4.8 within four months. This is why I recommend everyone consider eating a plant-based diet along with contaminant-free EPA and DHA to get the best of both worlds—omega-3 levels associated with brain preservation while minimizing exposure to toxic pollutants.


A list of my recommendations can be found here: Optimum Nutrition Recommendations.

Why not just eat fish or take fish oil? I explain why in these videos:

How else can we protect our brains? 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, year-in-review presentations:

Should We Increase Our Protein Intake After Age 65?

A study that purported to show that diets high in meat, eggs, and dairy could be as harmful to health as smoking supposedly suggested that “[p]eople under 65 who eat a lot of meat, eggs, and dairy are four times as likely to die from cancer or diabetes.” But if you look at the actual study, you’ll see that’s simply not true: Those eating a lot of animal protein didn’t have four times more risk of dying from diabetes—they had 73 times the risk. Even those in the moderate protein group, who got 10 to 19 percent of calories from protein, had about 23 times the risk of dying of diabetes compared to those consuming the recommended amount of protein, which comes out to be about 6 to 10 percent of calories from protein, around 50 grams a day.

So, the so-called low protein intake is actually the recommended protein intake, associated with a major reduction in cancer and overall mortality in middle age, under age 65, but not necessarily in older populations. When it comes to diabetes deaths, lower overall protein intake is associated with a longer life at all ages. However, for cancer, it seems to flip around age 65. I discuss this in my video Increasing Protein Intake After Age 65.

“These results suggest that low protein intake during middle age followed by moderate to high protein consumption in old adults may optimize healthspan and longevity.” Some have suggested that the standard daily allowance for protein, which is 0.8 grams of daily protein for every healthy kilogram of body weight, may be fine for most, but perhaps older people require more. The study upon which the recommended daily allowance (RDA) was based indicated that, though there was a suggestion that the “elderly may have a somewhat higher requirement, there is not enough evidence to make different recommendations.” The definitive study was published in 2008 and found no difference in protein requirements between young and old. The same RDA should be adequate for the elderly. However, adequate intake is not necessarily optimal intake. The protein requirement “studies have not addressed the possibility that protein intake well above the RDA could prove beneficial,” or so suggests a member of the Whey Protein Advisory Panel for the National Dairy Council and a consultant for the National Cattlemen’s Beef Association.

A study followed sedentary individuals over the age of 65 for 12 years and found they lose about one percent of their muscle mass every year. If you force people to lie in bed for days at a time, anyone would lose muscle mass, but older adults on bedrest may lose muscle mass six times faster than young people also on bedrest. So, it’s use it or lose it for everyone, but the elderly appear to lose muscle mass faster, so they better use it. The good news is that in contrast to the 12-year U.S. study, a similar study in Japan found that the “[a]ge-related decreases in muscle mass were trivial.” Why the difference? It turns out that in the Japanese study, “the participants were informed about the results of their muscle strength, [so] they often tried to improve it by training before the next examination.” This was especially true among the men , who got so competitive their muscle mass increased with age, which shows that the loss of muscle mass with age is not inevitable—you just have to put in some effort. And, research reveals that adding protein doesn’t seem to help. Indeed, adding more egg whites to the diet didn’t influence the muscle responses to resistance training, and that was based on studies funded by the American Egg Board itself. Even the National Dairy Council couldn’t spin it: Evidently, strength “training-induced improvements in body composition, muscle strength and size, and physical functioning are not enhanced when older people…increase their protein intake by either increasing the ingestion of higher-protein foods or consuming protein-enriched nutritional supplements.”

Is there anything we can do diet-wise to protect our aging muscles? Eat vegetables. Consuming recommended levels of vegetables was associated with basically cutting in half the odds of low muscle mass. Why? “[T]he alkalizing effects of vegetables may neutralize the mild metabolic acidosis” that occurs with age, when that little extra acid in our body facilitates the breakdown of muscle. I’ve discussed before how “[m]uscle wasting appears to be an adaptive response to acidosis.” (See my video Testing Your Diet with Pee and Purple Cabbage for more on this.) We appear to get a chronic low-grade acidosis with advancing age because our kidney function starts to decline and because we may be eating an acid-promoting diet, which means a diet high in fish, pork, chicken, and cheese, and low in fruits and vegetables. Beans and other legumes are the only major sources of protein that are alkaline instead of acid-forming. And indeed, a more plant-based diet—that is, a more alkaline diet—was found to be positively associated with muscle mass in women aged 18 to 79.

So, if we are going to increase our protein consumption after age 65, it would preferably be plant-based proteins to protect us from frailty. No matter how old we are, a diet that emphasizes plant-based nutrition “is likely to maximize health benefits in all age groups.”


What was that about a study that purported to show that diets high in meat, eggs, and dairy could be as harmful to health as smoking? See my video Animal Protein Compared to Cigarette Smoking.

Protein is so misunderstood. For more on the optimal amount of protein, see Do Vegetarians Get Enough Protein? and The Great Protein Fiasco.

Interested in learning more about the optimal source of protein? See:

What about the rumors that plant protein is incomplete? See The Protein Combining Myth.

For information on buffering the acid in our blood, see Testing Your Diet with Pee and Purple Cabbage.

And, for more on acid/base balance, 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, year-in-review presentations:

The Best Dried Fruit for Osteoporosis

“We are in an epidemic of osteoporosis. There can be no doubt about that.” Ten million Americans have it, and one in three older women will get it. “We urgently need public health strategies to maintain bone health throughout the life cycle and to prevent osteoporosis in later life.” Might fruits and vegetables be the unexpected natural answer to the question of osteoporosis prevention? My video Prunes for Osteoporosis sought to find out.

Evidence from a variety of studies “strongly points to a positive link between fruit and vegetable consumption and indexes of bone health,” such as bone mineral density, and the “size of the effect in the older women [is] impressive: doubling the fruit intake” is associated with a 5 percent higher spine mineralization. The same relationship exists with young women, too. And, eating lots of fruit in childhood may protect bones throughout life—something that was not found for milk intake, as I’ve explored before in my video Is Milk Good For Our Bones?

Bone health isn’t just about calcium. There are several key nutrients found in vegetables, fruits, and beans that are associated with better bone mineral density, but does that translate into lower hip fracture risk? The Singapore Chinese Health Study found that a “diet rich in plant-based foods, namely vegetables, fruit, and legumes such as soy, may reduce the risk of hip fracture.” But, why?

“The underlying mechanism in postmenopausal osteoporosis (PO) is an imbalance between bone resorption [disappearance] and formation,” and oxidative stress may play a role in this balance.

There are two types of bone cells: “the bone-forming osteoblasts and the bone-dismantling osteoclasts.” Osteoblasts are continually laying down new bone, while osteoclasts chisel away old bone, using free radicals as the molecular chisel to chip away our bone. Too many free radicals in our system, though, may lead to excessive bone breakdown. Antioxidant defenses appear “markedly decreased in osteoporotic women,” and “elderly osteoporotic women had consistently lower levels of all natural antioxidants tested than controls.”

“Because excessive [free radicals] may contribute to bone loss, it is important to elucidate the potential role antioxidant-rich fruits play in mitigating bone loss that leads to the development of osteoporosis.” The thought is that fruits up-regulate the bone building cells, and down-regulate the bone-eating cells, tipping the balance towards greater bone mass. So, let’s put a fruit to the test. Which one do we pick? Dried plums were chosen because they have among the highest antioxidant ranking among commonly consumed fruits and vegetables—and because the researchers received a grant from the California Dried Plum Board!

When you think of prunes, you think of bowels, not bones, but, over a decade ago, researchers at Oklahoma State tried giving a dozen prunes a day to a group of postmenopausal women, using a dozen dried apple rings as a control. After three months, only the subjects who consumed the prunes had significant elevations in an enzyme marker of bone formation, although prunes didn’t seem to affect markers of bone breakdown. So, prunes may help more with building bones than preventing bone loss. However, the reverse was found with almonds, so maybe a little prune-and-almond trail mix is in order. 

With this bump in bone formation indices, one might expect that if they did a longer study, we would actually see an impact on bone mineral density. And nine years later, just such a study was done: 12 months on dried plums versus apples. Both dried fruit regimens appeared to have “bone-protective effects,” though the prunes seemed to work better in the arm bone and spine.

So, the dried plum marketing board wants everyone to know that dried plums are “the most effective fruit in both preventing and reversing bone loss,” but only two fruits have ever been tested: plums and apples. If this pans out for other plants, though, “a ‘fruit and vegetables’ approach may provide a very sensible (and natural) alternative therapy for osteoporosis treatment, one that is likely to have numerous additional health-related benefits.” All we have to do is convince people to actually do it.


For more on bone health, see:

What else can prunes do for us? Check out Prunes vs. Metamucil vs. Vegan Diet.

Apple rings have their own benefits. See Dried Apples vs. 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, year-in-review presentations: