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.

结肠菌群可产生具有健康促进作用的代谢产物丁酸（butyrate）。本研究旨在通过向20名健康成年人的膳食中补充抗性淀粉（resistant starch，RS），以调控其体内丁酸的生成水平。尽管受试者粪便中丁酸的平均水平从8 mmol/kg湿粪便升至12 mmol/kg湿粪便，但个体间的应答反应差异显著。根据应答反应将受试者分为三类：应答增强型、高应答型与低应答型，各组样本量分别为11、3和6。应答增强型组的粪便丁酸水平提升了87%，而高应答型组的该水平维持在12 mmol/kg，低应答型组则维持在8 mmol/kg。微生物组（microbiome）分析结果显示，应答增强型与高应答型组中，降解抗性淀粉的微生物占比从约2%升至10%，而低应答型组的该占比仍维持在约2%。降解抗性淀粉的微生物占比未出现提升，这或许正是低应答型组受试者无法通过补充抗性淀粉获得丁酸生成益处的原因。本研究凸显了明晰个体间差异的重要性，这对于调控菌群所提供的生态系统服务具有关键意义。