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Research Reveals Vegans Have Low Omega-3 Levels

A recent study on blood omega-3 levels in vegans was accepted and is in press for publication in the medical journal Clinical Nutrition.1 The fatty acid analysis data was presented on more than 160 vegans who were not supplementing with DHA and EPA. DHA plus EPA levels were reported as the ‘omega-3 index’; the omega-3 index is the proportion of DHA + EPA (out of total fatty acids) in red blood cell membranes. It has been proposed that a low omega-3 index (lower than 4%) is a risk factor for heart disease.2 The average omega-3 index of the vegans in the study was 3.7%, in that potential risk factor range. A total of 64% of the vegans had levels lower than 4%, 27 percent had levels lower than 3%, and a small number (about 1%) had very low levels—lower than 2%. These result confirmed my findings over the last twenty-five years, seeing thousands of vegans and near vegans, many with fatty acid deficiencies resulting in medical issues.

Were these vegans just not eating enough flax, chia and walnuts? ALA is the omega-3 fatty acid found in these foods, and it is the precursor to DHA and EPA. However, the efficiency of this conversion of ALA to DHA and EPA varies tremendously between individuals, based on a number of dietary and genetic factors.3,4 On average, ALA intake among the vegans in the study was quite high—3.4 grams/day—more than double the adequate intake set by the U.S. Institute of Medicine. Higher ALA intake was not correlated with higher omega-3 index, suggesting that conversion efficiency is a more important determinant of DHA and EPA than ALA intake. Other studies have reported similar findings, and I have frequently observed deficiencies in my patients, even those who eat excellent diets with plenty of ALA-rich foods.5 Eating plenty of ALA-rich foods is simply not enough for many people to achieve sufficient DHA and EPA levels—supplementation is often necessary.

The major concern of a lack of DHA and EPA in the diet coupled with a lower conversion rate from ALA is an increased risk of brain shrinkage with age. Omega-3 fatty acids are crucial components of cell membranes in the human brain.6 Low levels of DHA in the blood are associated with age-related cognitive decline and Alzheimer’s disease.7,8 Multiple studies have shown that higher blood DHA and/or EPA correlates with greater brain volume (less brain shrinkage) or better brain function. Most recently, as published in Neurology, a greater omega-3 index was associated with greater brain volume in older women—total brain volume and also volume of the hippocampus, an area of the brain involved in long-term memory formation and storage.9,10 Also, older adults taking omega-3 supplements have shown improvements in learning and memory.11

Maintaining adequate omega-3 stores is crucial for assuring the late life health of your t brain. It is too risky to just assume your body will make the right amount of DHA to protect you later in life, especially if you follow a Nutritarian diet and expect to live until an unusually late age. It is best to think ahead. Plan for the future of your brain, because once you develop dementia, it is too late to fix it. Bottom line, either check your omega-3 fatty acid levels with a blood test to assure that you are sufficient, or take the supplement, or both.


1. Sarter B, Kelsey KS, Schwartz TA, et al: Blood docosahexaenoic acid and eicosapentaenoic acid in vegans: Associations with age and gender and effects of an algal-derived omega-3 fatty acid supplement. Clin Nutr 2014.
2. Harris WS: The omega-3 index as a risk factor for coronary heart disease. Am J Clin Nutr 2008;87:1997S-2002S.
3. Harnack K, Andersen G, Somoza V: Quantitation of alpha-linolenic acid elongation to eicosapentaenoic and docosahexaenoic acid as affected by the ratio of n6/n3 fatty acids. Nutr Metab 2009;6:8.
4. Davis BC, Kris-Etherton PM: Achieving optimal essential fatty acid status in vegetarians: current knowledge and practical implications. Am J Clin Nutr 2003;78:640S-646S.
5. Fokkema MR, Brouwer DA, Hasperhoven MB, et al: Short-term supplementation of low-dose gamma-linolenic acid (GLA), alpha-linolenic acid (ALA), or GLA plus ALA does not augment LCP omega 3 status of Dutch vegans to an appreciable extent. Prostaglandins Leukot Essent Fatty Acids 2000;63:287-292.
6. Higdon J: Essential Fatty Acids. In An Evidence-Based Approach to Dietary Phytochemicals. New York, NY: Thieme; 2006: 78-99
7. Yurko-Mauro K: Cognitive and cardiovascular benefits of docosahexaenoic acid in aging and cognitive decline. Curr Alzheimer Res 2010;7:190-196.
8. Yurko-Mauro K, McCarthy D, Rom D, et al: Beneficial effects of docosahexaenoic acid on cognition in age-related cognitive decline. Alzheimers Dement 2010.
9. Bowman GL, Silbert LC, Howieson D, et al: Nutrient biomarker patterns, cognitive function, and MRI measures of brain aging. Neurology 2011.
10. Pottala JV, Yaffe K, Robinson JG, et al: Higher RBC EPA + DHA corresponds with larger total brain and hippocampal volumes: WHIMS-MRI study. Neurology 2014;82:435-442.
11. Quinn JF, Raman R, Thomas RG, et al: Docosahexaenoic acid supplementation and cognitive decline in Alzheimer disease: a randomized trial. JAMA 2010;304:1903-1911.


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