Effect of whey protein on glucose tolerance and insulin sensitivity in Zucker Diabetic rats

There is some evidence that whey protein, may increase insulin sensitivity and decrease the risk of, or modulate the severity of type 2 diabetes. To test the hypothesis that a high whey protein diet would be more beneficial for type 2 diabetics than a high soy protein diet, Zucker Diabetic rats were placed on test diets at 5 weeks of age. Rats were fed test diets of either high soy protein or high whey protein for 8 weeks. There were no significant differences in food consumption or weight gain between groups. Body composition was analyzed by DXA and whey fed rats had a greater percent body fat than soy fed rats ( p = 0.035). At the end of 8 weeks on test diets the rats were implanted with ultrafiltrate probes and jugular catheters. The average daily glucose measured in interstitial fluid samples obtained with the ultrafiltrate probe showed at trend toward lower glucose in the whey fed rats (p = 0.07). Glucose tolerance tests were performed and glucose and insulin were measured. Glucose values measured in blood were significantly lower (p < .05) at baseline, C max and at 3 hours. The area under the curve (AUC) showed a trend toward lower glucose for whey fed rats ( p = 0.059). The AUC for ISF was significantly lower for whey fed rats than soy fed rats. There were no significant differences in insulin concentrations or insulin sensitivity. Conclusion: Whey protein provided some improvement in glucose tolerance. Support: National Dairy Council.