Tailored effects of coarse grain substitution on blood pressure via gut microbiota-metabolite networks and host gene variants: a randomized controlled trial

We previously reported inverse associations of coarse grain (CG) intake with blood pressure, mediated by metabolites and gut microbiota. In this 12-week randomized controlled trial among 172 prehypertension participants, both the CG (100 g/day) group and the control group (refined grain) showed significant reductions in systolic blood pressure (SBP) and diastolic blood pressure (DBP) over 12 weeks, with no significant time by group interaction. In the exploratory analyses of secondary outcomes, significant time by group interactions were detected for 26 taxa (such as g__Lactococcus and g__Faecalibacterium), associated with 23 differential fecal metabolites, which in turn were correlated with blood pressure changes over the CG intervention. Microbial ATP-binding cassette transporter was highlighted in the pathway annotation for the CG-derived differential microbial taxa. Baseline gut microbiota exhibited predictive potential for blood pressure reduction, while host ABO variance rs514659 modulated the intervention effect on SBP and DBP (P interaction < 0.05), providing preliminary evidence for the tailored nutrition strategies optimizing blood pressure and gut microbiota profiles.