#Japan #Kyoto #Gut Microbiome #Kyoto University #Noster Inc

Research Overview

A research collaboration between Kyoto University and Noster Inc. has provided groundbreaking insights into the relationship between gut bacteria and obesity, particularly in the context of high-sugar diets. Focused on a specific gut bacterium, Streptococcus salivarius, the study reveals this bacterium's unique ability to transform sucrose, a type of sugar, into beneficial exopolysaccharides (EPS). These EPS are subsequently metabolized into short-chain fatty acids (SCFAs) by other gut microbes, playing a crucial role in metabolic health.

Key Findings

The Fight Against Obesity

Obesity is a pressing global health issue, driven in part by increased sugar consumption. The researchers identified a prominent protective role for S. salivarius against the adverse effects of consuming high amounts of sucrose. Unlike other bacteria, S. salivarius produces large quantities of EPS, which are complex carbohydrates that the human body cannot digest but act as prebiotics. These prebiotics nourish beneficial gut microorganisms that produce SCFAs, critical compounds for regulating energy metabolism, reducing fat accumulation, and enhancing insulin sensitivity.

Detailed Research Steps

1. Microbial Screening: The research team screened over 470 human donors for gut bacteria and identified S. salivarius as a significant EPS producer in individuals with lower body mass index (BMI). In contrast, obese individuals exhibited significantly reduced levels of this beneficial bacterium.
2. Mouse Models: The study included experiments on obese mice subjected to high-fat diets. When supplemented with S. salivarius-derived EPS, these mice demonstrated considerable reductions in weight gain and fat deposition, alongside lowered blood glucose levels compared to control groups, underscoring the protective effects of this bacterium.
3. SCFA Production: The team discovered that the EPS produced by S. salivarius are further fermented by gut microbes such as Bacteroides into SCFAs like acetate and propionate. These SCFAs interact with host receptors to help regulate metabolism and energy balance.
4. Genomic Analysis: Utilizing advanced sequencing methods, researchers identified specific genes in S. salivarius responsible for EPS production, including glycosyltransferases and levansucrases, crucial enzymes for building these polysaccharides.

Implications for Health

This discovery positions S. salivarius as a potential biomarker for metabolic health and resistance to obesity. Its ability to convert sucrose into health-boosting compounds opens the door for the development of probiotic supplements and functional foods designed to enhance gut health and improve metabolic balance. According to Ikuo Kimura, the leading researcher from Kyoto University, leveraging the properties of S. salivarius can pave the way for innovative solutions to tackle obesity and associated metabolic disorders.

Glossary

• - Exopolysaccharides (EPS): Complex sugar molecules produced by certain bacteria that serve as food for beneficial gut bacteria.
• - Short-Chain Fatty Acids (SCFAs): Important compounds created during the fermentation of dietary fibers by gut bacteria, which help regulate metabolism and inflammation.
• - Glycosyltransferases and Levansucrases: Enzymes that enable bacteria to assemble polysaccharides from simple sugars like sucrose.
• - Prebiotics: Non-digestible components of food that promote the growth of beneficial gut bacteria.

Research Reference

Shimizu, H., Miyamoto, J., Hisa, K. et al. Sucrose-preferring gut microbes prevent host obesity by producing exopolysaccharides. Nat Commun 16, 1145 (2025). https://doi.org/10.1038/s41467-025-56470-0.

Company Overview

Noster Inc.: Conducting pioneering research related to biopharmaceuticals and functional foods, with its headquarters in Kyoto, Japan. For further inquiries, contact Public Relations at Noster Inc.