Role of B vitamins in modulating homocysteine and metabolic pathways linked to brain atrophy: Metabolomics insights from the VITACOG trial

Abstract INTRODUCTION Elevated total homocysteine (tHcy) is a major predictor of brain atrophy, cognitive decline, and Alzheimer's disease (AD) progression. The VITACOG trial, a randomized, placebo‐controlled study in mild cognitive impairment (MCI), previously showed that B vitamin supplementation lowered tHcy, slowing brain atrophy and cognitive decline; however, the underlying mechanisms remained unclear. METHODS We used untargeted, multi‐platform metabolomics, with nuclear magnetic resonance and liquid chromatography‐mass spectrometry to analyze serum samples from 89 B vitamin–treated and 84 placebo‐treated MCI participants over a 2 year follow‐up period. RESULTS Multivariate modeling distinguished treated from placebo groups with 91.2 ± 1.8% accuracy. B vitamin supplementation induced significant metabolic reprogramming, lowering quinolinic acid, α‐ketoglutarate, α‐ketobutyrate, glucose, and glutamate. DISCUSSION These findings reveal that B vitamins influence metabolic pathways beyond tHcy reduction, particularly the tricarboxylic acid cycle and glutamine–glutamate cycling, critical for brain energy homeostasis and neurotransmission. This metabolic signature supports B vitamin supplementation as a strategy for slowing MCI progression. Highlights Nuclear magnetic resonance and multi‐platform liquid chromatography tandem mass spectrometry metabolomics were performed on serum samples from 89 B vitamin–treated and 84 placebo participants in the VITACOG trial. Multi‐platform metabolomics revealed B vitamin–driven metabolic reprogramming, achieving 91% classification accuracy. B vitamin supplementation modulates key neuroprotective metabolic pathways. Regulation of energy metabolism and neurotransmission by B vitamins contributes to brain health in elderly individuals. B vitamins demonstrate potential as an adjunct therapy in mild cognitive impairment, potentially mitigating progression to Alzheimer's disease.