The
antidiabetic effects of lactic acid bacteria were investigated using mice. In Experiment 1, normal ICR mice were loaded with
sucrose or
starch with or without viable Lactobacillus rhamnosus GG cells. GG significantly inhibited postprandial
blood glucose levels when administered with
sucrose or
starch. In Experiment 2, KK-A(y) mice, a model of genetic
type 2 diabetes, were given a basal diet containing viable GG cells or viable Lactobacillus delbrueckii subsp. bulgaricus cells for 6 weeks. Viable GG cells significantly inhibited fasting
blood glucose, postprandial
blood glucose in a
glucose tolerance test and HbA1c. Such effects were not shown by viable L. bulgaricus cells. In Experiment 3, the KK-A(y) mice were given a basal diet containing viable GG cells or heat-treated GG cells for 3 weeks. The viable GG cells significantly suppressed fasting
blood glucose and
impaired glucose tolerance, but the heat-treated GG showed no effects. These results demonstrated that GG decreased the postprandial
blood glucose in ICR mice, and that the
antidiabetic activity of lactic acid bacteria on the KK-A(y) mice differed depending on the bacterial strain and whether the bacterium is viable when it arrives in the intestine. In the present study, we conclude that the
antidiabetic activity may result from continuous inhibition of the postprandial
blood glucose through suppression of
glucose absorption from the intestine. These findings indicate that specific strains of
lactic acid bacterium can be expected to be beneficial for the management of
type 2 diabetes.