γ -Polyglutamic acid ( γ -PGA) is a major component of Natto. We hypothesized that γ -PGA could reduce postprandial glucose rise and plasma glucose levels. Mice were fed a 0.1% γ -PGA — containing diet or control diet for 91 days. Maltose and starch tolerance tests were performed, and plasma lipids, glucose levels, and caecal short chain fatty acids (SCFAs) were measured. Mice were co-administered γ -PGA and starch to suppress the initial rise in blood glucose levels. Blood glucose levels at 15 min were significantly lower in the PGA group than in the Con group ( P < 0.05). The plasma glucose level and NEFA level were also significantly lower in the PGA group ( P < 0.05), and caecal acetic acid/total caecal SCFAs ratio was significantly increased in the PGA group ( P < 0.05) . Significant negative correlations existed between the caecal acetic acid/propionic acid ratio and the weight of visceral fat/BW (r = - 0.57, P = 0.0318). Our results suggest that γ -PGA may effectively prevent metabolic syndrome by lowering blood glucose levels.
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