A proteome-wide Mendelian randomisation study reports that genetically predicted branched-chain amino acid levels track with 40 circulating proteins, six of which, including PCSK9, SHBG and coagulation factor II, appear to partly mediate the link between BCAAs and ischaemic heart disease, accounting for 6.5% to 32.1% of the association. The pathways implicated involve inflammation, coagulation, lipid metabolism and cellular stress.
What it shows: Genetic (Mendelian randomisation) analysis of existing large datasets, not a feeding trial: it uses genetic proxies for BCAA levels, not measured dietary BCAA or supplement intake, and mediation estimates rest on modelling assumptions. Findings are mechanistic hypotheses needing experimental confirmation.Study · J Nutr