Vegan diet: micro algae help against Omega-3 deficiency

In vegans, the level of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), quantified with the Omega 3 Index, is rather low. But there is a solution: in fact, in those who follow a diet without foods of animal origin, the lack of these fatty acids can be compensated by taking supplements derived from microalgae. 

This is what emerges from the research of a group of scientists from the University of San Diego and the University of North Carolina (USA) who, in a study published in the journal Clinical Nutrition, investigated the effectiveness of EPA and DHA supplements in vegans.

Diets beneficial for the heart

As reported by several studies, people who follow a vegan or vegetarian diet have a very low risk of being affected by heart disease, even if their intake of EPA and DHA (the heart-healthy Omega 3s ) is low.

The heart benefits of these diets may be due to the low intake of saturated fat and the high consumption of fiber, phytochemicals, and fatty acids such as ALA (alpha-linolenic acid), the main form of Omega 3 in the vegan diet; however, the human body is not able to efficiently convert ALA to EPA and DHA, and taking ALA supplements leads to only a small increase in plasma EPA levels, and an even smaller increase in DHA. Therefore, the question remains whether this reduced intake of EPA and DHA could translate into health risks.

Vegans respond effectively to Omega 3 treatment

The aim of the authors of the study published in Clinical Nutrition was twofold: to confirm the deficiency of Omega 3 in those who have been following a vegan diet for a long time, examining the influence of factors such as age and sex and comparing the levels of Omega 3 in vegans with those detectable in omnivores, and to verify whether any deficiency of Omega 3 found in vegans could be improved by taking an EPA and DHA supplement compatible with their dietary choices.

For this reason, the researchers measured the Omega 3 Index in a group of vegans and compared it with that previously detected in a group of omnivorous soldiers with similar characteristics, except for the fact that they followed a diet based on non-vegetarian military rations but not rich in Omega 3. 

The Omega 3 Index is a measure of the level of EPA and DHA and provides information on the intake of these two molecules; in practice, it corresponds to the percentage of EPA and DHA on the total fatty acids present in the membranes of red blood cells. Since 2004, this factor has represented a measure of the risk of death from coronary heart disease: a value below 4% indicates a high probability of cardiovascular disease, while values above 8% correspond to a low risk situation.

Measurements on the vegans involved in this study showed an average Omega 3 Index value of 3.7%, similar to that previously found in omnivorous soldiers (3.5%). However, the variety of results was greater in the vegan subjects: in 64% it was less than 4%, in 27% it was less than 3% and in 1% it did not even reach 2%; only in 2 cases was an Index higher than 8% (the minimum desirable value) detected. The values were generally higher in women than in men – probably due to the greater ability to obtain EPA and DHA from ALA typical of women before menopause. 

In the second phase of the study, a portion of the subjects in the vegan group, all with an Omega 3 Index lower than 4%, took a daily supplement of EPA and DHA (about 250 mg total) of microalgal origin. After 4 months, in 87% of cases the Omega 3 Index had exceeded 4%; the average value, equal to 3.1% before the supplement, had increased to 4.8%.

Algae-based supplements to increase the Omega 3 Index

Based on these results, the researchers concluded that most people who follow a diet free of animal products have very low levels of EPA and DHA (but not lower than omnivores who consume little Omega 3). 

The data obtained suggest that the response of vegans to the intake of microalgae-based supplements is very positive, although conditioned by factors such as age and sex, and allows to improve the levels of EPA and DHA in the body even at relatively low doses. Therefore, the use of Omega 3 supplements derived from microalgae, compatible with veganism, could actually mitigate any negative consequences of the lack of EPA and DHA due to the choice not to eat fish typical of vegan diets.

Confirmations from new studies

Subsequent studies have confirmed the results and conclusions reached by the authors of this research. In particular, a randomized controlled study published in 2023 in the European Journal of Nutrition by a group of researchers from the Department of Metabolism and Nutrition of the Institute of Food Science and Technology and Nutrition in Madrid (Spain) has shown that a microalgae supplement rich in DHA allows to increase the levels of DHA in the blood of those who follow a vegan diet.

The vegans in this study had higher blood levels of ALA and LA (linoleic acid, the progenitor of Omega 6 fats) than those found in a group of omnivores. Taking a DHA supplement from microalgae increased blood levels of this Omega 3 fat, increased the ratio of EPA to ALA, and improved the ratio of Omega 6 to Omega 3 in the blood – a parameter that, if excessively unbalanced in favor of Omega 6, is associated with a pro-inflammatory state and other unwanted health phenomena.

More generally, already in 2017 a review of the studies collected in the scientific literature, published in the Journal of Human Nutrition and Dietetics by a group of Australian researchers, came to the conclusion that the integration of DHA from microalgae improves the levels of this fat in the plasma, serum, platelets and red blood cells of vegetarian populations, confirming its potential as an ally against Omega 3 deficiencies often found in those who limit, or even eliminate, their intake of EPA and DHA from food.

Bibliographic references:

Craddock JC, Neale EP, Probst YC, Peoples GE. Algal supplementation of vegetarian eating patterns improves plasma and serum docosahexaenoic acid concentrations and omega-3 indices: a systematic literature review. J Hum Nutr Diet. 2017 Dec;30(6):693-699. doi: 10.1111/jhn.12474

García-Maldonado E, Alcorta A, Zapatera B, Vaquero MP. Changes in fatty acid levels after consumption of a novel docosahexaenoic supplement from algae: a crossover randomized controlled trial in omnivorous, lacto-ovo vegetarians and vegans. Eur J Nutr. 2023 Jun;62(4):1691-1705. doi: 10.1007/s00394-022-03050-3

Sarter B, Kelsey KS, Schwartz TA, Harris WS. 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. 2015 Apr;34(2):212-8. doi: 10.1016/j.clnu.2014.03.003