Metabologenomic approach reveals the feature of intestinal environment associated with barley-induced blood parameter improvements in Japanese cohort: a randomised controlled trial

Consumption of barley has been known to have beneficial effects on metabolic disorders; however, the inter-individual difference in the response has also been reported. Recent evidences have suggested that such individually different effects are mediated by the intestinal environment. Therefore, to understand its mechanisms, evaluating both intestinal environment and metabolic disorders marker is crucial. Here we report a randomised controlled trial in Japanese subjects with 4-week consumption of barley or control-food. In this study, we analysed intestinal environment, which include both microbiota and their metabolites by metabologenomic approach, and blood parameter were integratedly assessed. We found that groups of subjects who exhibited the improvement in glucose tolerance and reduction of total cholesterol by barley consumption were predictable by machine learning from their intestinal metabologenomic data. Also, rate of increase in abundance of cholesterol-degrading bacteria ([Eubacterium] coprostanoligenes group) by barley consumption in subjects who showed decrease in total cholesterol was significantly higher than the other subjects, which may contribute to the reduction of blood total cholesterol. Our findings indicate the effects of barley consumption are partly defined by the intestinal environment of consumers, which shed light on quantitative measurement of dietary effect from intestinal environment.