Gut microbiome, lipopolysaccharide and butyrate responses to cereal fibre-based interventions in overweight and obese adults: a pilot study

Cereal fibre modulates the gut microbiome and improves metabolic health. An understanding of any potential interaction between these effects is not yet clear, particularly, if there is a different effect with different cereal fibre types. This research aimed to measure changes to microbiome composition, butyrate and lipopolysaccharide levels in response to intake of specific cereal fibres. Overweight and obese healthy adults were provided with 45 g of four different cereal fibre interventions for three weeks each with three weeks washout between interventions in a randomised crossover design. Dietary intake was measured during each intervention period using a 3 day food record. Microbiome composition, serum butyrate and LPS levels were measured before and after each intervention. In ten subjects that completed all cereals, alpha diversity was reduced after moderate beta glucan intakes. Minor significant changes to microbiome composition were evident with different fibre types including increased Rhodospirillales post moderate beta glucan intake compared to only 2 percent post sorghum intake. No significant outcomes associated with beta-diversity, butyrate production or LPS levels were noted. This research provides evidence for different responses in microbiome composition with different cereal fibre types in overweight and obese adults and highlights the inter-individual responsiveness to diet. Further research is required before conclusions can be drawn regarding mechanistic links between cereal fibre, microbiome characteristics and metabolic risk.

谷物纤维可调节肠道菌群（gut microbiome）并改善代谢健康。目前尚不清楚这两类效应间是否存在潜在相互作用，尤其是不同谷物纤维类型是否会产生不同效应这一问题仍有待阐明。本研究旨在探究摄入特定谷物纤维后，肠道菌群组成、丁酸（butyrate）与脂多糖（lipopolysaccharide，LPS）水平的变化。本研究采用随机交叉试验设计，招募超重与肥胖健康成年人，为其提供四种不同的谷物纤维干预剂（每日45g），每种干预持续三周，且两次干预之间设置三周的洗脱期。在每个干预周期内，通过3天饮食记录法评估受试者的膳食摄入情况。在每次干预前后，分别检测受试者的肠道菌群组成、血清丁酸与脂多糖水平。在完成全部四种谷物纤维干预的10名受试者中，摄入适量β-葡聚糖（beta glucan）后，肠道菌群的α多样性出现降低。不同纤维类型可引起肠道菌群组成出现小幅但具有统计学意义的变化：例如，摄入适量β-葡聚糖后，受试者肠道内红螺菌目（Rhodospirillales）的相对丰度升高，而摄入高粱（sorghum）纤维后该菌目相对丰度仅升高2%。未观察到与β多样性、丁酸生成或脂多糖水平相关的显著变化。本研究证实，超重与肥胖成年人的肠道菌群组成对不同谷物纤维的响应存在差异，同时凸显了个体间对膳食干预的应答异质性。未来仍需开展更多研究，方能阐明谷物纤维、肠道菌群特征与代谢风险之间的潜在机制关联。