Dr. Greger Fan Questions Supplementing with EPA and DHA

Let me guess, you’re either plant-based or vegan, you follow Dr. Greger’s videos, and you’ve been taking (or considered taking) an EPA + DHA supplement, because Dr. Greger said so.

I have the greatest respect for the folks at NutritionFacts.org. Also, in good scientific spirit, this is my question to you: Have you looked more deeply into the studies Dr. Greger relies on for this specific recommendation? I have, and based on looking more closely, EPA + DHA supplements still have unproven necessity and safety. Let me develop.


Table of contents

  1. Some Basics
  2. What’s wrong with Dr. Greger’s recommendation to take an EPA + DHA supplement?
  3. Less is more – Understanding Omega-6 vs. Omega-3 metabolic pathways
  4. But do these simple dietary modifications provide enough EPA and DHA?
  5. Conclusions
  6. APPENDIX: Admiration, even well-deserved, can cloud critical thinking

Some Basics

Omega-3 fatty acids are important for health. The parent form of it, alpha-linolenic acid, (ALA) is an essential fatty acid, we must get that one from our food. The human body, depending on lifestyle and other factors, converts ALA more or less efficiently into other omega-3s: EPA, then DHA.

The omega you don’t need more of is omega-6. The parent form, linoleic acid (LA), is also essential but widely over-consumed, and is found typically in high-fat plant foods (vegetable oils, nuts and seeds, etc…). Both ALA and LA are found in every unprocessed plant food, in various amounts and ratios.


What’s wrong with Dr. Greger’s recommendation to take an EPA + DHA supplement?

Dr. Greger’s argument in favour of DHA for all vegans relies on one interventional study linking EPA+DHA intake with health benefits: slight improvement at a cognitive test + what’s interpreted as physically improved brain structure and lower grey matter loss. The supplement was fish oil (EPA + DHA), in high doses (per day: 1320 mg EPA + 880 mg DHA).

Any major flaws? Yes, many. The study published in 2013 was done on:

  • Healthy people? Unfortunately, no. Intentionally selected overweight people 25<BMI<30 with – not surprisingly – blood work that’s really not great (hypertension, borderline high cholesterol by the overly-lenient current official standards, etc.).
  • The general public? No. Seniors only (age 50-75).
  • People eating a healthy plant-based diet? No, people who often eat fish.
  • Identical groups? No, the experimental group (the ones taking the supplement) exercised more.
  • Was their diet well-controlled to ensure both groups ate the exact same food, and that the benefit comes only from the supplement? Again, no. The fish intake was measured only 3 one-off times in 26 weeks. Fish intake is also reported by frequency instead of by quantities of EPA/DHA content.
  • Was the intake of plant-based omega-3 from food recorded? No.

So yes, it is a double-blind, placebo-controlled study, and also serves a perfect example of how this “gold standard” can be far from enough. The design of the study matters as well. Here it is rather poor. More importantly this study really says nothing about vegans and people eating a low-fat whole food plant-based (WFPB) diet.

Moreover, and ironically: While the study uses 880 mg DHA per day, Dr. Greger himself reports that a similar dose (800 mg DHA) is dangerous, based on a study showing that in pregnant (omnivorous) women this DHA dose leads to having children with learning difficulties.

“In a study in which women were given a whopping 800 mg of DHA a day during pregnancy, infant girls exposed to the higher-dose DHA in the womb had lower language scores and were more likely to have delayed language development than girls from women in the control group.”

I am aware that Dr. Greger recommends much less than that toxic dose (250 mg of mixed EPA and DHA), but why is he resting his case on a study so poorly designed and using a toxic dose? Mystery.

Part of that mystery was unveiled since. That study actually isn’t the source of inspiration of his recommendation, although it may seem like it is. Dr. Greger’s recommendation for EPA or DHA precedes this 2013 study. Back in 2008 he was already advocating for DHA,  based on pregnancy/child cognition/child vision studies on omnivores. I looked into them, they display generally poorly controlled/documented diets and outcomes of questionable relevance.

His observation in another 2008 video, that “people who don’t eat animals (…) have very low levels of long-chain omega 3s”, and subsequent recommendation to supplement, is based on a study on high-fat vegans. Their diet was comprised of ~33% fat by % of total calories, in short a very high-fat and high-omega-6 diet, not a healthy low-fat, whole-food plant based one. In the section that follows I’ll explain why a low fat content in the diet matters to synthesize EPA and DHA from ALA.

Again, I have great respect for Dr. Greger and the NutritionFacts.org team of researchers.  Simply, at this point in time, the evidence to support necessity and safety of this supplementation regime is weak, and irrelevant to vegans or people on low-fat whole food plant-based (WFPB) nutrition.


Less is more – Understanding Omega-6 vs. Omega-3 metabolic pathways

Modern diets contain an excess of omega-6, typically from vegetable oils and excessive consumption of high-fat plant foods (nuts, avocados, etc…), and animal products. This interferes with our ability to convert ALA into EPA and DHA. Why? Because omega-6 conversions “steal” the enzymes that omega-3s need to convert ALA into EPA and DHA, and also the enzymes for the latter to be utilised.

Some enzymes in this process have a preference for converting omega-3s, but overwhelmed by a crowd of omega-6s (like in the average vegan or non-vegan diet) they process omega-6s. Also, the omega-3 conversions take more steps, which gives omega-3 an extra handicap in the competition against omega-6. Finally, these enzymes have nutrient “co-factors”, meaning that they need all sorts of nutrients to function well. Hence the importance of unprocessed diets, which are more nutrient-dense and less prone to nutrient deficiencies and the subsequent enzyme dysfunctions.

Cutting down our fat consumption, starting with oils and processed foods, and eating more of a low-fat, whole food plant-based (WFPB) diet does a number of good things with omega-3s:

  • reduces drastically omega-6s intake => omega-3s have less competition => more omega-3 converted and used
  • increases the intake of omega-3s (healthy fats like omega-3s, just like protein, are everywhere in low-fat, unprocessed plant foods)
  • increases the nutrient intake => the enzymes rely on those nutrients (co-factors) to convert ALA omega-3s into EPA and DHA.
  • For reasons unrelated to omega-3s, you’ll feel energetic, loose the extra pounds, and prevent or reverse illness. You wouldn’t read this article and wouldn’t have an interest in supplements if you didn’t to some extent value you health, would you?

Do these simple dietary modifications provide enough EPA and DHA?

This has already been discussed here by rockstar nutritionist Jeff Novick in this article (UPDATE: unfortunately the article was removed after I recently pointed out to Jeff that only a few lines of that old article had obsolete data. I’ll update with Jeff Novick’s analysis on omega-3 whenever I find it elsewhere, or with his updated article, whichever comes first. For now read this.)

Long story short, two scenarios:

A) If you eat a well-planned whole food plant-based (WFPB) diet:

  • We’re assuming your diet is low in fat (~10% of total calories), oil-free, varied, and you’re generally healthy and seldom drink alcohol (yep, alcohol affects omega-3 metabolism).
  • You should be fine and achieve similar excellent overall and brain health , just like the many WFPB populations documented throughout the world.
  • This diet should provide enough ALA to meet the Adequate Intake (AI): 1.1g/day for women and 1.6g for men  as set originally by the U.S. National Academy of Sciences; average Western body sizes. (I log my food very occasionally only for educational purposes, my omega-3 intakes as ALA always meets and exceeds the AI).
  • Enough DHA and EPA should be formed by conversion of ALA under those ideal conditions (low-fat, high-nutrient diet).
  • The studies saying that humans poorly convert ALA, or finding low serum levels in vegans are based on people eating unhealthy diets, typically a high-fat diet (>28–40% of energy as fat). There is a case for omega-3 studies done on people eating a WFPB diet, to reveal conversion rates, and perhaps point to optimal levels of ALA in the diet by looking at health outcomes of various intakes instead of comparing blood levels with fish-eaters. Realistically, we won’t see that data anytime soon…
  • To be on the extra-safe side, you can have (if you deem necessary) 1 or 2 Tbsp (tablespoons) of ground flaxseed daily.
    Note: Time, heat, and exposure to air make these healthy fats oxidise and turn into harmful fats. It can’t harm to blend a new batch as frequently as conveniently possible (we do weekly) and keep it in a closed container in the fridge. Although walnuts and chia seeds are also high in omega-3, I stick to using and advocating flaxseed because:

    • Walnuts are most often bought unshelled, prone to oxidation (going rancid), easily overeaten (health-wise counter-productive), and more expensive.
    • Chia seeds are most often eaten whole (they should be ground for any omega-3 benefit), and are more expensive.
    • Flaxseed conveniently has a thick shell that prevents oxidation until you grind on demand, has the highest content of omega-3, comes with other health benefits (high fiber content, plays a role in preventing/reversing prostate cancer with lignans, reduces blood pressure, etc.), and is the cheapest. Who wins? Flaxseed of course!

B) If you’re currently eating more of a “junk food” type of vegan/plant-based diet (processed foods, using oil/margarines, high-fat, etc) and/or consume alcohol frequently:

  • The odds are your diet is deficient in omega-3s, all of them.
  • Even if you were to have ground flaxseeds (high in ALA) or an omega-3 supplement (ALA, not EPA+DHA), you’d likely very poorly convert it to EPA and DHA because of the high-fat, processed and in some cases alcohol-abusing nature of the diet.
  • You might benefit from some sort of EPA+DHA omega-3 supplementation. Everybody agrees that evidence on benefits and risks is still not clear at this point.
  • An EPA+DHA supplement will, at best, only limit in a minor way the damage of this lifestyle.
  • Consider going at least oil-free/low-fat, and preferably also whole food plant-based.

Conclusions

While the West is pondering about EPA and DHA supplementation or not for vegans, in a short-sighted manner and based on reductionist studies, epidemiology has long demonstrated that quasi-fully plant-based societies that refrain from aquatic animals (fish, etc) have thrived, i.e. unmatched excellent health at all stages of life + long healthspan. This should be the reference, not fish-eaters with fish fat running in their blood. The low-fat WFPB societies achieved unmatched health with zero effort put into omega-3 supplementation, and without foods high in omega-3s like ground flaxseed, walnuts or ground chia seeds.

Additionally, before considering a supplement, it must in my view tick ALL these boxes:

  1. proven necessary (confers health benefits, prevents illness, essential nutrient not found in our diet)
  2. proven safe for long-term use
  3. proven irreplaceable: the active ingredient cannot realistically/practically be obtained in sufficient/safe amounts by dietary means within a plant-based diet.

At this point, nothing suggests EPA and DHA pass those tests.

A low-fat WFPB diet is what vegans should consider as a first line of action if they are concerned with their omega-3 status and the consequences it might have on overall health (including neurological/mental/cognitive).

The omega-3 talk among healthy “whole foodies” is at best one of fine-tuning and optimisation, not a matter or life, death or illness – at all. If you are consuming a low-fat, WFPB diet, with ground flaxseed, the precious time of a healthy person is best spent spreading health and helping other people know about WFPB, rather than worrying about any other nutrients than B12, and the nutrients deficient/unavailable in whatever soil your food grows.

This article was focused on assessing the grounds of Dr. Greger’s recommendation and offering an alternative. If you want to find out more details/debate about the relevance or not of EPA/DHA in a vegan or whole-food plant-based diet, Dietician Dominic Marro has written an excellent article below. It notably compiles the positions of notorious WFPB advocates and plant-based doctors:
Do You Need to Supplement With EPA and DHA If You Follow a Whole Food Plant-Based Lifestyle?

Disclaimer: There may be health conditions where omega-3s are poorly absorbed or poorly converted. In those cases the position shared here might not apply, but only concerns healthy individuals.


APPENDIX: Admiration, even well-deserved, can cloud critical thinking

It’s no surprise to anyone that Dr. Greger from Nutritionfacts.org is looked up to in the vegan and plant-based communities; Dr. Greger (learn the spelling folks, “reger” is symmetrical if that helps 😉 ) and his team of ~19 researchers, whom I would like to salute and acknowledge for a change). The NutritionFacts.org team has compiled countless highly educational videos on various aspects of health and nutrition. So it’s no wonder people having learned so much from them hold Dr. Greger and his team in high regard, he’s become a bit of a nutrition research God.

Like with all veneration, the downside of such admiration is that it clouds reason, and leads to something I jokingly coin as:

Gregerscepticopenia: The lack of healthy scepticism, commonly found in a Dr. Greger admirer, towards a view or position held by Dr. Greger.

Dr. Greger is a media. A media literally means an inter-media-ry, in this case between followers and the published science, itself a media between us readers and (when done honestly) a reality scientists observed through experiments they carried out and documented. Thankfully, in good scientific spirit, the website shares the sources so everybody can look into them. And if you do look into them, sometimes, especially when the supporting evidence is weak or preliminary, you’ll have good reasons to disagree with Dr. Greger’s positions, assumptions, interpretations, conclusions, practical advice.

Even true heroes have their flaws. Even the most genuinely truth-oriented people deserve some healthy scepticism, because humans are humans. Such scepticism is good because it would spot unwitting mistakes and get them corrected, raise the standards of scientific practice, and also because you might not agree with someone’s conclusions/convictions when looking at the same raw data.

Let’s all try to break out from the culture of “following” people, and instead be actors of truth-seeking. Let’s try to make a habit to question things even from our heroes, by going to the source of information and judging for ourselves.