Gut Microbes and Acetate Synergy Promote Fat Loss in Mice Without Muscle Wastage

Researchers led by Hiroshi Ohno at the RIKEN Center for Integrative Medical Sciences in Japan have uncovered a novel approach to combating obesity. Their recent study demonstrates that increasing acetate levels in the gut, coupled with the presence of specific bacteria from the Bacteroides genus, can significantly reduce fat deposits and liver mass in both normal and obese mice. This effect is achieved without the loss of muscle tissue, which is a common concern in weight loss strategies.

The team discovered that when mice are supplemented with an acetate-based compound called AceCel, they experience notable weight reduction. The key lies in the interaction with gut bacteria; the presence of Bacteroides enhances acetate’s ability to boost the fermentation of sugars in the intestines, leading to increased fat oxidation. Consequently, mice utilize more liver fat for energy instead of carbohydrates, mirroring metabolic states seen during fasting or ketogenic diets.

Further investigations revealed that the beneficial effects depend heavily on the gut microbiota's composition. In experiments where mice lacked Bacteroides bacteria, AceCel showed no impact on weight or liver health. Conversely, in mice with specific Bacteroides species, similar positive outcomes were observed, confirming that the synergy between acetate and these bacteria is essential.

At a mechanistic level, the combination promotes carbohydrate fermentation, reducing available sugars for energy conversion. This shifts the energy reliance toward fat burning and prevents excess sugar storage in the liver—a process that contributes to obesity.

Dr. Ohno emphasized the significance of these findings, stating, "Developing treatments that target the gut microbiome offers a promising avenue for obesity management. Our work with acetylated cellulose shows that modulating gut bacteria and their metabolic activities could be both effective and safe."

Looking ahead, the research team aims to investigate the safety and potential application of acetylated cellulose in humans, with hopes of developing functional foods that could serve as preventative or therapeutic options against obesity.

This groundbreaking research highlights the complex interplay between diet, gut microbiota, and metabolic health, paving the way for innovative interventions in obesity management.

For more information, see the original study: Tadashi Takeuchi et al, "Acetylated cellulose suppresses body mass gain through gut commensals consuming host-accessible carbohydrates," Cell Metabolism (2025). Source: https://medicalxpress.com/news/2025-05-gut-bacteria-acetate-team-fat.html