Managing human microbiomes: Explaining heterogeneous responses in butyrate to dietary supplementation with resistant starch

Colonic bacteria produce the health-promoting metabolite butyrate. We sought to influence butyrate production in 20 healthy adults by supplementing their diet with resistant starch (RS). While average fecal butyrate increased from 8 to 12 mmol/kg wet feces, responses varied widely between individuals. Three types of responses were categorized: enhanced, high, and low (n = 11, 3, and 6 respectively). Fecal butyrate increased by 87% in the enhanced group, while it remained ≥12 mmol/kg in the high group and ≤8 mmol/kg in the low group. Microbiome analyses revealed that RS-degrading organisms increased from ~ 2 to 10% in the enhanced and high groups, but remained at ~ 2% in the low group. This lack of increase in RS-degrading microbes is likely why individuals in the low group do not benefit in butyrate with RS. This study underscores the importance of understanding inter-individual variability in managing ecosystem services from microbiomes.