Effects of γ-Polyglutamic Acid on the Cecal Microbiota and Visceral Fat in KK-Ay/TaJcl Male Mice

Natto is a major functional food in Japan. γ-Polyglutamic acid (γ-PGA) is one of the main components of Natto, and beneficial effects of γ-PGA have been reported. We tested the hypothesis that γ-PGA alleviates metabolic syndrome in KK-Ay/TaJcl male mice. These mice were fed a diet containing 0.5% of γ-PGA or a control diet for 28 days. Visceral fat was significantly smaller in the PGA group than in the CON group. The amounts of lipids in feces (dry weight) sampled on the final day of the experiment and cecal Lactobacillus counts were significantly greater in the PGA group than in the CON group. Cecal Prevotella counts tended to be higher in the PGA group. These results suggest that dietary γ-PGA affects the cecal microbiota and ameliorates accumulation of visceral fat in the KK-Ay/TaJcl mouse model of type 2 diabetes mellitus.