Not just vegetarians and vegans: microalgae supplements effective for omnivores too

Often presented as an alternative to fish oil for those who don't consume animal products, microalgae supplements also represent a valid option for omnivores. Evidence in a study from the European Journal of Nutrition.

It's no longer news: even those who don't consume fish products (like vegans and some vegetarians) can obtain the bioactive Omega-3s present in these sources that are absent from plant-based foods. Microalgae contain EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) - the same Omega-3s found in fish - and can be used to produce vegetarian and vegan-compatible supplements.

Now we have proof these same supplements are good EPA/DHA sources for omnivores too. This was demonstrated in a study published in the European Journal of Nutrition by researchers from Madrid's Instituto de Ciencia y Tecnología de Alimentos y Nutrición (Spain) led by Pilar Vaquero.

This confirmation is good news for anyone avoiding fish-derived products for reasons beyond vegetarianism/veganism - like those who dislike even the taste of purified, flavored fish oil supplements.

Why prefer EPA/DHA supplements?

The need for preformed EPA/DHA supplements stems from humans' limited ability to produce them from their precursor, alpha-linolenic acid (ALA).

Unfortunately, Omega-3 sources compatible with fish-free diets (like often-cited walnuts, flaxseeds and their oils) contain ALA, not EPA/DHA. After absorption, ALA converts first to EPA then DHA through such inefficient reactions that <5% of available ALA becomes EPA; some studies suggest even lower conversion rates, especially in men.

Thus even with "land-based" plant supplements, vegetarians/vegans risk EPA/DHA deficiency - particularly during pregnancy or hypertriglyceridemia when bioactive Omega-3 requirements increase.

Fortunately, the alternative exists: microalgae oil. Like marine animal sources (fish oil, cod liver oil, krill oil), microalgae oil contains preformed bioactive Omega-3s, mainly DHA.

After all, microalgae form the food chain base enabling krill/fish to accumulate DHA/EPA. We now cultivate them for supplements whose ability to increase vegetarians'/vegans' blood DHA levels is well-documented.

A 2017 Journal of Human Nutrition and Dietetics analysis by Joel C Craddock et al. confirmed improvements in plasma/serum/platelet/red blood cell DHA concentrations and the Omega-3 Index (a heart health risk indicator) in fish-free diets. But are these products suitable for fish-eaters?

Omnivores: when isn't fish oil suitable?

This question matters because even omnivores sometimes avoid fish oil supplements. The most common reason is the fishy aftertaste, sometimes noticeable despite sophisticated purification processes.

Krill oil could be an alternative - unless you're allergic to shellfish, which would contraindicate it.

These and other reasons might lead fish-eaters to choose microalgae oil for Omega-3 supplementation.

Microalgae oil: supplementation for all

The European Journal of Nutrition study confirmed a Schizochytrium-algae DHA supplement's effectiveness at increasing blood DHA in vegan/lacto-ovo-vegetarian adults, adding two key details:

1) Just 250 mg daily DHA (the maximum allowed in EU-authorized Schizochytrium supplements) suffices;

2) The same supplement/dose also increases omnivores' blood DHA.

Vaquero's team randomly assigned 116 volunteers to receive either a Schizochytrium DHA supplement (625 mg total lipids, including 250 mg DHA) or indistinguishable olive oil placebo (625 mg).

Participants took one capsule daily with a main meal (for optimal absorption) for 5 weeks, then none for 5 weeks, then switched groups for 5 more weeks. Otherwise, they maintained normal lifestyles (diet/exercise).

All completed health/lifestyle questionnaires initially and at weeks 5, 10 and 15. Fasted blood DHA levels were measured initially and at weeks 5, 10 and 15. "Significant diet, treatment and diet×treatment effects were observed," the authors report.

Specifically, blood DHA levels:

1) Under placebo, were highest in omnivores, followed by lacto-ovo-vegetarians then vegans;

2) Increased significantly (vs placebo) in all groups with microalgae supplementation, with relatively greater effect in vegans (though neither vegetarian group reached omnivores' levels);

3) Increased similarly in men and women (who generally had higher DHA concentrations).

"These results," the authors state, "lead us to conclude all participants with low/no DHA intake would benefit from the tested DHA supplement."

Microalgae supplements are 'bioavailable and useful'

"These results," Vaquero's team concludes, "clearly demonstrate DHA supplements from Schizochytrium sp. microalgae are bioavailable and useful for increasing circulating levels of this important long-chain Omega-3."

Schizochytrium supplements "have great potential" both because "many plant-based diet consumers could benefit" and because "among omnivores, those not eating fish or who shouldn't consume seafood (e.g., due to Anisakis allergies) could likewise benefit, as could general population members open to [trying] new formulations, supplements and functional foods."

How much microalgae DHA for how long?

As noted, Vaquero's results used 250 mg daily microalgae DHA for 5 weeks.

The duration wasn't arbitrary: it's generally recognized that weeks are needed for dietary Omega-3s to incorporate into cell membranes.

Is the dose sufficient for health benefits? The Italian Society of Human Nutrition recommends all adults get 250 mg daily DHA+EPA, while EFSA states 250 mg DHA supports normal brain function and vision.

Want to optimize your Omega-3 intake with supplements? Ask our pharmacists for advice!

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

European Commission. Food and Feed Information Portal Database. Last accessed: 03/02/2025

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

Italian Society of Human Nutrition-SINU, 2014. LARN - Reference intake levels for the Italian population: LIPIDS. Last accessed: 03/02/2025