Dietary bacterial cellulose modulates gut microbiota and increases bile acid excretion in high-fat diet-induced obese mice

• Bacterial cellulose (BC) suppresses weight gain, fat accumulation, and cholesterol. • BC has a high bile acid (BA) binding capacity and increases the excretion of BA. • BC increases beneficial gut bacteria such as Bacteroides and Ruminococcus . • BC does not enhance the production of short-chain fatty acids. Bacterial cellulose (BC), with its unique and highly viscous nanofiber structure, was the focus of this study. We investigated BC supplementation's potential for body weight management and its effects on gut microbiota and bile acid metabolism in high-fat diet (HFD)-fed mice. Mice were categorized into four groups: BC-untreated group on a control-fat diet (CF), BC-untreated group on an HFD (UHF), medium BC-treated group on an HFD (MHF), and high BC-treated group on an HFD (HHF). Over 12 weeks, BC supplementation significantly reduced body weight gain, fat accumulation, and plasma total cholesterol levels compared to the UHF group. Metabolomic analysis revealed that BC intake upregulated the bile acid biosynthesis pathway. The fecal analysis confirmed that bile acid excretion was highest in the HHF group, with increased plasma bile acid levels. BC's bile acid-binding capacity was 3.2 times greater than that of cellulose, contributing to these metabolic effects. Gut microbiota analysis showed that BC increased beneficial bacteria, including Bacteroides and Ruminococcus , which are involved in polysaccharide metabolism. However, BC intake did not enhance short-chain fatty acid production. These findings highlight BC's potential as a dietary intervention for obesity and cholesterol management through its effects on bile acid metabolism and gut microbiota.