Effects of mastication on glucose metabolism in rats, with emphasis on differences in properties of food consumed whilst breeding

Objective: In this study, to elucidate the effects of preferred properties of food that affect the daily masticatory habits on the onset of lifestyle-related disease, we investigated whether groups of rats continuously fed with diet having distinct properties show differences in glucose metabolism. Design: Thirty-six male Wistar rats aged 4 weeks were divided into two groups; only the pellet type feed was given to one (solid diet group), and the powdered feed to the other (powder diet group). The oral glucose tolerance test (OGTT) was performed to measure glucose metabolism. For the determination of statistical significance (p < 0.05), blood glucose level and areas under the blood glucose response curve (AUC) were analysed using the Mann-Whitney U-test. Results: The AUC values were significantly different between the two diet groups when the animals were 45 and 51 weeks of age. The median blood glucose level in 45-week-old rats fed with the powder diet was significantly higher than those in age-matched rats fed with solid diet 45 and 120 min after glucose load. Similarly, the median blood glucose level in the 51-week-old rats in the powder diet group was significantly higher than those in the solid diet group at 30, 45, 60, and 120 min after glucose load. Conclusions: We showed that the rats which had been fed with solid diet and therefore had been masticating the feed plentifully enhanced glucose metabolism. This can suggest the possible use of masticatory and dietary intervention, which promotes sufficient mastication of hard food, in the prevention and cure of human lifestyle-related diseases. (C) 2011 Elsevier Ltd. All rights