Vegan Diet: Microalgae Help Against Omega-3 Deficiency

In vegans, the level of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), quantified by the Omega-3 Index, is quite low. But there is a solution: in those following a diet free of animal products, the deficiency of these fatty acids can be compensated by taking supplements derived from microalgae. 

This is the conclusion from research conducted by 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 efficacy of EPA and DHA supplements in vegans.

Heart-healthy diets

As reported by several studies, people following vegan or vegetarian diets have a very low risk of heart disease, even though their intake of EPA and DHA (the Omega 3 allies of the heart) is minimal. 

The cardiac benefits of these diets may be due to their low saturated fat intake and high consumption of fiber, phytochemicals, and fatty acids such as ALA (alpha-linolenic acid), the main form of Omega-3 in vegan diets; however, the human body cannot efficiently convert ALA into EPA and DHA, and ALA supplementation results in only a slight increase in plasma EPA levels and an even smaller increase in DHA. Thus, it remains unclear whether this reduced intake of EPA and DHA poses 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 Omega-3 deficiency in those following a long-term vegan diet, exploring the influence of factors such as age and sex and comparing Omega-3 levels in vegans with those found in omnivores; and to verify whether any detected Omega-3 deficiency in vegans could be improved by taking an EPA and DHA supplement compatible with their dietary choices.

To this end, the researchers measured the Omega-3 Index in a group of vegans and compared it with that previously measured in a group of omnivorous soldiers with similar characteristics, except that they followed a non-vegetarian military ration diet low in Omega-3. 

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

Measurements taken on the vegans involved in this study showed an average Omega-3 Index value of 3.7%, similar to that previously measured in omnivorous soldiers (3.5%). However, the variability of results was greater among vegans: in 64% it was below 4%, in 27% it was below 3%, and in 1% it did not even reach 2%; only in 2 cases was an Index above 8% (the minimum desirable value) detected. Values were generally higher in women than in men – probably due to women’s greater ability to obtain EPA and DHA from ALA, especially before menopause. 

In the second phase of the study, some subjects in the vegan group, all with an Omega-3 Index below 4%, took daily an EPA and DHA supplement (about 250 mg total) derived from microalgae. After 4 months, in 87% of cases the Omega-3 Index exceeded 4%; the average value, which was 3.1% before supplementation, rose to 4.8%.

Algal-based supplements to increase the Omega-3 Index

Based on these results, the researchers concluded that most people following a diet without animal products have very low levels of EPA and DHA (but not lower than omnivores with low Omega-3 intake). 

The data suggest that vegans respond very positively to microalgae-based supplements, although influenced by factors such as age and sex, and can improve their EPA and DHA levels even at relatively low dosages. Therefore, the use of Omega-3 supplements derived from microalgae, compatible with veganism, could effectively mitigate potential negative consequences of EPA and DHA deficiency due to the choice not to eat fish typical of vegan diets.

Confirmations from recent studies

Subsequent studies have confirmed the findings and conclusions reached by the authors of this research. In particular, a randomized controlled trial 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 Nutrition Technologies in Madrid (Spain) demonstrated that a microalgae supplement rich in DHA increases blood DHA levels in those following a vegan diet.

Vegans involved in this study showed higher blood levels of ALA and LA (linoleic acid, the progenitor of Omega-6 fats) compared to those observed in a group of omnivores. Taking a microalgae DHA supplement increased blood levels of this Omega-3 fat, increased the ratio of EPA to ALA, and improved the Omega-6 to Omega-3 ratio in the blood – a parameter that, if excessively skewed towards Omega-6, is associated with a pro-inflammatory state and other undesirable health effects.

More generally, as early as 2017 a review of studies collected in the scientific literature, published in the Journal of Human Nutrition and Dietetics by a group of Australian researchers, concluded that DHA supplementation from microalgae improves levels of this fat in 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 completely exclude EPA and DHA intake from foods.

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