Potential mental and physical benefits of supplementation with a high-dose, B-complex multivitamin/mineral supplement: what is the evidence?

Objective: to perform a systematic literature review to examine the effects of high-dose, B-complex multivitamin/mineral supplementation on physical, mental, and energy outcomes in healthy and 'at-risk' (suboptimal nutritional status/subclinical symptoms at baseline) adult populations. Methods: PubMed was searched for relevant randomized controlled trials until January 2020. Results: overall, 136 publications were identified. In the seven randomised, double-blind, placebo-controlled studies considered eligible for inclusion, supplementation in healthy populations predominantly showed improvements in perceived stress, physical stamina, concentration, and general mental health, and significant reductions in anxiety and improvements in self-reported vigour. However, not all of these outcomes were significant, and statistical correction for multiple outcomes was not commonly employed. Studies investigating brain mapping following supplementation indicated increased functional activity in brain regions related to processing of attention, executive control, and working memory during cognitive tasks. Conclusions: while there is certainly a need for further studies on the neurocognitive and physical benefits of micronutrient supplementation, this review provides generally supportive evidence for the benefits of a high-dose, B-complex multivitamin/mineral supplement in healthy and at-risk populations in terms of physical, mental, and energy outcomes.