Effects of co-ingestion of glucose with high-protein, high-fat milk products after exercise on glucose-dependent insulinotropic polypeptide and insulin secretions in collegiate students

Abstract

【Aim】

Because insulin promotes muscle glycogen and protein synthesis, post-exercise nutritional strategies designed to augment insulin secretion might be effective for athletes. We previously reported that co-ingestion of glucose and milk stimulates insulin secretion after exercise, possibly through enhancement of the secretion of glucose-dependent insulinotropic polypeptide （GIP） by the protein and fat intake. In this study, we examined whether co-ingestion of glucose and high protein and fat-containing milk products can further increase the secretions of GIP and insulin.

【Methods】

Eight collegiate students completed a 30-min cycle ergometer exercise on 3 separate occasions. Immediately after each exercise, they ingested either 1） a glucose solution, 2） glucose + high-fat milk, or 3） a high-protein, high-fat milk jelly containing glucose, water, whole-fat milk powder, fresh cream and gelatin. Blood samples were collected before and after intake of these supplements to determine the plasma GIP and insulin levels.

【Results】

While the areas under the curve for plasma GIP were significantly higher after the ingestion of glucose + high-fat milk and glucose + high-protein, high-fat milk jelly as compared with that after ingestion of glucose solution, no significant differences in the plasma insulin levels were observed among the trials.

【Conclusion】

These results suggest that co-ingestion of glucose and high protein and fat-containing milk products can induce further increase in the plasma GIP level, but not insulin, in healthy collegiate students.