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Randomized Controlled Trial
. 2022 Oct;61(7):3731-3739.
doi: 10.1007/s00394-022-02924-w. Epub 2022 Jun 15.

DHA status influences effects of B-vitamin supplementation on cognitive ageing: a post-hoc analysis of the B-proof trial

Annick P M van Soest  1 , Ondine van de Rest  2 , Renger F Witkamp  2 , Tommy Cederholm  3 , Lisette C P G M de Groot  2
Affiliations
Randomized Controlled Trial

DHA status influences effects of B-vitamin supplementation on cognitive ageing: a post-hoc analysis of the B-proof trial

Annick P M van Soest et al. Eur J Nutr. 2022 Oct.

Abstract

Purpose: Trials aiming to lower homocysteine by B-vitamin supplementation have reported mixed results on slowing cognitive decline. We investigated if efficacy of B-vitamin supplementation is affected by baseline plasma omega-3 fatty acid levels.

Methods: This post-hoc analysis of the B-proof trial included 191 adults aged 65 years or older with baseline plasma total homocysteine ≥ 12 μmol/L, randomly assigned to 400 µg folic acid and 500 µg vitamin B12 or placebo daily for 2 years. Global and domain-specific cognitive functioning were assessed at baseline and after 2 years. The effect of B-vitamin supplementation was analyzed according to tertiles of baseline plasma omega-3 fatty acids concentrations combined, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) individually using multiple linear regression analyses.

Results: The mean ± SD age of the participants was 71.6 ± 5.9 years and median [IQR] Mini-Mental State Examination was 29 [28-30]. The treatment effect of B-vitamins on global cognition was larger in participants in the high compared to the middle DHA tertile (difference in z-score, mean ± SE 0.22 ± 0.10, p = 0.03). There was no significant interaction between B-vitamin supplementation and combined omega-3 fatty acid (p = 0.49) and EPA (p = 0.99) tertiles. Similarly, the efficacy of B-vitamin treatment on domain-specific cognitive functioning did not link to omega-3 fatty acid, DHA, or EPA plasma levels.

Conclusion: This post-hoc analysis indicated that efficacy of B-vitamin supplementation in slowing cognitive decline relates to DHA status, with individuals with higher plasma DHA levels benefitting more from vitamin B12 and folic acid use. The results support earlier observations that positive effects of B-vitamins in cognitive ageing may be subgroup-specific.

Trial registration: Registered at clinicaltrials.gov (NCT00696514) on June 12, 2008.

Keywords: B-vitamins; Cognition; Elderly; Healthy ageing; Older adults; Omega-3 fatty acids.

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Conflict of interest statement

The authors have no relevant financial or non-financial interest to disclose.

Figures

Fig. 1
Fig. 1
Changes in Z-scores (mean β ± SE) in global cognition over the two year intervention period according to treatment group and A omega-3 fatty acid status, B eicosapentaenoic acid (EPA) status and C docosahexaenoic acid (DHA) status. *Significant (p < 0.05) difference in treatment effect between omega-3 fatty acid tertiles, as analyzed by linear multiple regression
See this image and copyright information in PMC

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