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

Elena García-Maldonado, Alexandra Alcorta, Belén Zapatera, M Pilar Vaquero, Elena García-Maldonado, Alexandra Alcorta, Belén Zapatera, M Pilar Vaquero

Abstract

Purpose: To determine serum fatty acids of lacto-ovo vegetarian (LOV), vegan (VEG) and omnivorous (OMN) adults, and to analyse the effects of consuming a docosahexaenoic acid (DHA) supplement of vegetable origin on fatty acid profile.

Methods: A randomized, double-blind, placebo-controlled crossover design was conducted in healthy adults. Volunteers (n = 116) were randomly assigned to a DHA-supplement (dose 250 mg/day), made from the microalgae Schizochytrium sp., or a placebo during 5-week periods separated by a 5-week washout interim period. Compliance and dietary intake were estimated and serum fatty acids were determined by gas chromatography. Results were analysed by mixed linear models.

Results: Percentage of linoleic acid (C18:2n6) in serum was the highest among the fatty acids in the three diet groups, followed by oleic (C18:1n9) and palmitic (C16:0) acids. Linoleic (C18:2n6) and alpha-linolenic (C18:3n3) acids were higher in VEG compared to OMN (p < 0.001), while in LOV, their levels were intermediate between the other groups. Women presented higher DHA (C22:6n3) than men (p < 0.001). The DHA-supplement increased serum DHA compared to placebo in the three diet groups (p < 0.001), and a higher increase was observed in VEG followed by LOV (p < 0.001). The ratio serum n-6/n-3 improved by the supplementation but remained higher in LOV and VEG than in OMN. In contrast, the DHA-supplement decreased docosapentaenoic (C22:5n3) and docosatetraenoic (C22:4n6) acids in all diet groups (p < 0.001) and increased the eicosapentaenoic to alpha-linolenic fatty acids ratio (p = 0.016).

Conclusion: The DHA-supplement at dose of 250 mg/day was effective in increasing serum DHA either in omnivorous, lacto-ovo vegetarian and vegan adults.

Clinical trial registration: Registered at Clinicaltrials.gov ( www.

Clinicaltrials: gov ), NCT04278482.

Keywords: Docosahexaenoic acid; Fatty acids; Omega-3; Omega-6; Supplementation; Vegan; Vegetarian.

Conflict of interest statement

The authors declare that they have no conflicts of interest.

© 2022. The Author(s).

Figures

Fig. 1
Fig. 1
Consolidated Standards for Reporting Trials (CONSORT) flow diagram
Fig. 2
Fig. 2
Change in serum DHA after intake the DHA-supplement or placebo, according to diet group and gender. OMN omnivorous, LOV lacto-ovo vegetarian, VEG vegan. All three diet groups were significantly different after DHA-supplement (p < 0.001) and there were no significant differences between diet groups after placebo. The differences between men and women were not significant (ANOVA)
Fig.3
Fig.3
Biosynthesis of long chain polyunsaturated fatty acids in humans and changes due to vegetarian diets and DHA supplementation of the present randomized controlled trial. Fatty acids analyzed in this study are in bold. Δ6: desaturase Δ6; Δ5: desaturase Δ5; Δ: desaturase Δ9; Elon: elongase. Differences due to diet type: open arrows indicate significantly increased or decreased in lacto-ovo vegetarians and/or vegans compared to omnivorous. Changes due to the DHA supplementation: dark arrows indicate significant increase or decrease after consumption of the DHA-supplement in the three diet groups

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