Omega-3 Supplementation For Brain Health? Not Yet.

Dr. Greger is recommending that people consume a “contaminant-free EPA and DHA” supplement. (EPA and DHA are omega-3 fatty acids, the long-chain type):


His recommendation was based on several studies, some of which he highlights in his video. The clincher for him was this one:

Blood Docosahexaenoic Acid And Eicosapentaenoic Acid In Vegans: Associations With Age And Gender And Effects Of An Algal-Derived Omega-3 Fatty Acid Supplement, Clinical Nutrition, April 2015

Conclusions: We conclude that vegans have low baseline omega-3 levels, but not lower than omnivores who also consume very little docosahexaenoic and eicosapentaenoic acids. The vegans responded robustly to a relatively low dose of a vegetarian omega-3 supplement.

Should we take a vegetarian omega-3 (n3) supplement? I don’t think so. Some thoughts I have about this study:

  • The group of 167 vegans had an n3 index about equal to the omnivores (3.7%). If low n3 is a problem, it’s a problem for everyone, not just vegetarians.
  • In this study, vegans’ red blood cell membranes “responded robustly” to an omega-3 supplement. Did vegans’ brains respond robustly? Blood n3 may correlate with brain n3, but this particular study was not able to determine whether the supplement ended up in the brain, or whether taking a supplement can cause higher levels of n3 in the brain.
  • Changing the structure of the brain is not the same as changing the function of the brain. Does taking n3 change memory or cognition? In what way? Are the changes always desirable? Dr. Greger mentioned a study of 30 women who took 2.2 grams of fish oil a day and did see improvement in executive function after 6 months. But this larger, longer, and more recent study, in this report didn’t find benefit:

    While some research suggests that a diet high in omega-3 fatty acids can protect brain health, a large clinical trial by researchers at the National Institutes of Health found that omega-3 supplements did not slow cognitive decline in older persons. With 4,000 patients followed over a five-year period, the study is one of the largest and longest of its kind.

  • Will taking a vegetarian omega-3 supplement decrease risk for other diseases (diabetes, heart disease, cancer) in vegans? Vegans already have lower rates of these diseases than omnivores. This study didn’t elucidate.
  • There was no control group. On this topic of group comparison, there was no group that took the shorter-chain alpha-linolenic acid (ALA, the kind of n3 you find in flax). That would have been a good comparison because it might have shown you didn’t have to take an expensive n3 supplement to achieve the same effect. Why not include that group? Read on…
  • There may be conflicts of interest among the researchers. Dr. Joel Fuhrman provided the n3 supplement used in the study. He also sells the supplement and recommends taking it, as an “insurance policy.” One of the authors, William Harris, is the President of OmegaQuant Analytics which provided the fatty acid analyses for this study. OmegaQuant sells an omega-3 test kit and advocates “the use of omega-3 fatty acids to improve health.”
  • There are safety concerns involved in supplementing with omega-3. We know that omega-3s increase risk for prostate cancer. It may increase bleeding although this is still debated. It may lead to downregulation of ALA–>EPA+DHA. That means the n3 in the flax you eat might not easily get converted to EPA and DHA and might lead to dependency on the supplement.
  • The polyunsaturated fatty acids in the pill easily go rancid:

    So what’s wrong with eating rancid oils?

    “There are at least two,” says lipid specialist and University of Massachusetts professor Eric Decker. “One is that they lose their vitamins, but they also can develop potentially toxic compounds” that have been linked to advanced aging, neurological disorders, heart disease and cancer.

    “They’re carcinogenic, pro-inflammatory and very toxic,” says integrative medicine specialist Andrew Weil. “They are also widespread in the food chain.”

I think it’s a big deal to tell people to start taking an expensive supplement for the rest of their lives … a supplement that comes with increased risks for disease, a supplement that is poorly regulated. While I appreciate Dr. Greger’s work, and often agree with him, I have no plans to start taking vegan omega-3.


1 thought on “Omega-3 Supplementation For Brain Health? Not Yet.

  1. Pingback: Dr. Greger May Have Unwittingly Recommended Seafood Consumption | Fanatic Cook

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