Accumulating evidence to date suggests that brown rice is superior to white rice in regards to its beneficial impact on a number of risk factors of the metabolic syndrome (MetS). However, little is known about the influence of fermented brown rice beverage on the gut microbiota in humans. We therefore hypothesized that its impact would beneficially alter the gut microbiota composition of patients with MetS. Employing a 4-week randomized, single-arm study design, subjects (n=40) were advised to consume a daily fermented brown rice beverage (BA) or fermented white rice beverage (WA) in replace of their main meal. Clinical and anthropometric measurements as well as fecal samples were collected at baseline and immediately at the completion of the intervention. Gut microbiota was analyzed using 16S rRNA sequencing and capillary electrophoresis-time-of-flight mass spectrometry (CE-TOFMS) was used to measure plasma levels of short chain fatty acids (SCFAs). Interestingly, ingestion of BA in contrast to WA, resulted in a unique elevation in the abundance of number of beneficial species belonging to the Clostridia class, associated with reduced inflammation, and increased short chain fatty acid production; Lactobacillales bacterium DJF B280 (P=0.005), Butyrate producing bacterium A2 207 (P=0.012) and Firmicutes bacterium DJF VP44 (P=0.038). This study demonstrates that consumption of BA is effective in beneficially modulating the gut microbiota compared to WA in patients with MetS. CLICK TO REVIEW