Journal pre-proof published online: 11 July 2026
Original research article
Vegan Multinutrient Supplementation Significantly Increases Omega-3 Index and 25-OH-Vitamin D Status: A Randomized, Double-Blind, Placebo-Controlled Trial in Healthy Young Vegans
Tim Zerback ∙ Christian Koeder ∙ Stine Weder ∙ Andreas Sputtek ∙ Gunter P Eckert ∙ Markus Keller
Highlights
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Vegan supplement improved omega-3-index and vitamin D in healthy vegans.
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Control group showed decline in omega-3-index and vitamin D status.
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Benefits achieved with modest daily EPA and DHA doses from algae oil.
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Novel use of estimated omega-3 index from serum validated against erythrocytes.
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4-month RCT demonstrates efficacy of vegan omega-3 supplementation.
Abstract
In this randomized, double-blind, placebo-controlled trial, 72 healthy vegan adults (aged 19–57 years) received a multinutrient supplement consisting of a vitamin and mineral supplement (providing 26 µg vitamin D) and an omega-3 supplement administered in either a single dose (EPA 98.7 mg, DHA 171.0 mg, additional vitamin D 36 µg, vitamin E 3.7 mg) or a double dose (EPA 197.4 mg, DHA 342.0 mg, additional vitamin D 72 µg, vitamin E 7.4 mg) or placebo capsules for 4 months. Nutrient biomarkers were assessed at baseline and at the end of the intervention after 4 months. An analysis of covariance was employed to test for between-group differences (p < 0.05) and adjusted for multiple testing using the Bonferroni-Holm method. Compared to the control group, which showed on average a significant decline in both the omega-3-index and 25-hydroxyvitamin D, participants in both intervention groups demonstrated significant increase in these parameters (p < 0.001). Although the double dose group exhibited numerically greater increases in omega-3 index and vitamin D compared to the simple dose group, the differences between these dosing regimens were not statistically significant. As expected, vitamin E levels remained unchanged, reflecting its inclusion solely for antioxidative protection in the omega-3 supplement rather than as a critical nutrient in vegan diets. In conclusion, supplementation significantly improved omega-3 and vitamin D status in healthy vegans, with no significant benefit from doubling the dose. Although clinical endpoints were not evaluated, improved nutrient status may have potential implications for health.
https://doi.org/10.1016/j.plefa.2026.102759
Alternative link: https://www.plefa.com/article/S0952-3278(26)00037-2/abstract
This article is not open access.
