Effects of co-ingesting glucose and whey protein on blood glucose, plasma insulin and glucagon concentrations, and gastric emptying, in older men with and without type 2 diabetes

Aim: To investigate whether co-ingestion of dietary protein with, or before, carbohydrate may be a useful strategy to reduce postprandial hyperglycaemia in older men with type 2 diabetes (T2D).Materials and Methods: Blood glucose, plasma insulin and glucagon concentrations were measured for 180 minutes following ingestion of a drink containing 30 g of glucose (G; 120 kcal), 30 g of whey protein (120 kcal), 30 g of glucose plus 30 g of whey protein (GP; 240 kcal), or control (similar to 2 kcal) in older men with T2D (n = 10, 77 +/- 1 years; 31 +/- 1.7 kg/m(2)) and without T2D (n = 10, 78 +/- 2 years; 27 +/- 1.4 kg/m(2)). Mixed model analysis was used.Results: GP versus G markedly reduced the increase in blood glucose concentrations (P < .001) and had a synergistic effect on the increase in insulin concentrations (P < .001), in men both with and without T2D. Glucose concentrations were higher in men with T2D compared with those without T2D, whereas insulin and glucagon concentrations were largely unaffected by the presence of T2D. Gastric emptying was faster in men with T2D than in those without T2D.Conclusions: The ability of whey protein to reduce carbohydrate-induced, postprandial hyperglycaemia is retained in older men with T2D compared with those without T2D, and whey protein supplementation may be a useful strategy in the prevention and management of T2D in older people.