Fermented Soybean Suppresses Visceral Fat Accumulation in Mice

• Published in: Molecular nutrition & food research 2018-09, Vol.62 (17), p.e1701054-n/a
• Main Authors: Kushida, Mamoru, Okouchi, Ran, Iwagaki, Yui, Asano, Masaki, Du, Ming Xuan, Yamamoto, Kazushi, Tsuduki, Tsuyoshi
• Format: Article
• Language: English
• Subjects: Adipocytes; Adipose Tissue - cytology; Animals; Anti-Obesity Agents - pharmacology; Body Weight; Carbohydrate metabolism; Carbohydrates; Catabolism; Diet; Diet, High-Fat - adverse effects; Fatty acids; Fermentation; Fermented Foods; fermented soybeans; Gastrointestinal Microbiome - genetics; Gene Expression Regulation; gut microbiota; High fat diet; Hypertrophy; Intestinal microflora; Intra-Abdominal Fat - growth & development; Lipid Metabolism - genetics; Liver; Liver - metabolism; Male; Metabolism; Mice; Mice, Inbred C57BL; Microbiota; Natto; Oxidative metabolism; Oxidative stress; Soy Foods; Soybeans; visceral fat accumulation
• ISSN: 1613-4125; 1613-4133
• DOI: 10.1002/mnfr.201701054

Scope Mice are fed a soybean diet before or after fermentation in the present work to allow direct comparison of the antiobesity effect of fermentation. Methods C57BL6J mice were fed high‐fat diets containing boiled soybeans (prefermentation) or Natto (postfermentation) for 4 weeks. Prefermented cooked soybeans or Natto was added at levels of 2.5 and 5%, which are the amounts that can be ingested in a normal diet once and twice a day. In addition, mice gut microbiota from fecal samples were analyzed to explore the mechanisms of effects caused by fermentation. Results Natto intake significantly reduced visceral fat in a dose‐dependent manner, inhibited hypertrophy of adipocytes, improved carbohydrate metabolism, and reduced oxidative stress. These effects were seen in mice fed soybeans before fermentation, but were stronger in mice fed Natto. Therefore, soybean intake has beneficial effects and fermentation of soybeans enhances these effects. Natto was found to suppress fatty acid synthesis and promote fatty acid catabolism in the liver. These effects were also stronger with Natto compared with soybeans before fermentation. In addition, Natto had more potent beneficial effects on gut microbiota compared to soybeans. Conclusions These results suggest that Natto intake supports maintenance of health. The effect on obesity of dietary Natto intake in mice fed a high‐fat diet with that in mice fed the same amount of boiled soybeans are compared. Natto intake significantly reduces visceral fat in a dose‐dependent manner, inhibited hypertrophy of adipocytes, improved carbohydrate metabolism, and reduced oxidation stress.