Abstract
Oats have various positive effects on human health, but the underlying mechanisms are not fully understood. To determine the oat-microbiome-host interactions that contribute to metabolic improvements, we conducted a randomized, short-term dietary intervention with high-dose oat intake in individuals with metabolic syndrome (DRKS00022169). Thirty-two participants completed the trial. We find that the two-day oat diet improves lipid metabolism by lowering serum total cholesterol by 8 % and low-density lipoprotein cholesterol by 10 %, accompanied by distinct changes in plasma and fecal metabolomic profiles and gut microbiota. These induced alterations, particularly an increase in microbially produced phenolic compounds, correlate inversely with changes in cholesterol levels, suggesting that plasma phenolic compounds are driving factors for the cholesterol-lowering effect of oats, besides the known mechanisms of β-glucan. This newly identified mechanism might be of great potential since a short-term, high-dose oat diet is a suitable and rapid approach to alleviate obesity-related lipid disorders.