Metabolic Effects of a Pre-meal Protein Drink With or Without Added Amino Acids at a Subsequent Composite Meal

Hyperglycaemia in type 2 diabetes (T2D) is associated with an increased risk of cardiovascular diseases, and it has been suggested that reduction of postprandial glycaemia is just as important as lowering fasting blood glucose levels to reach optimal metabolic control and reduce risk of complications in T2D. Observational studies indicate that milk consumption reduces the risk of developing T2D, obesity and cardiovascular disease, and a possible protective mechanism has been ascribed to the protein fraction. It has previously been demonstrated that addition of whey proteins, co-ingested with carbohydrates, stimulates insulin secretion and reduces postprandial glycaemia in both healthy subjects as well as in T2D patients. The effect is mediated through the insulinogenic properties of whey that appears to stem from a generation of a particular amino acid (AA) pattern in postprandial blood after ingestion of whey proteins. In the presently described project it is hypothesized that exchanging part of the whey protein for insulinogenic AA might be useful to optimize an insulinogenic effect. Additionally, soy protein has been suggested to have beneficial effects on insulin resistance and obesity as well on satiety. The possible effect of soy protein on insulin response and glycaemic regulation is therefore also of interest.

A randomized, single blind, within-subject trial was performed. The test meals were provided as breakfasts on 7 different occasions in random order with approximately 1 week between each test. The test subjects were instructed to drink the protein drink immediately prior to eating the standardized sandwich meal. Altogether, the protein drink and the sandwich meal were to be consumed within 12 min.

Inclusion criteria

• normal fasting blood glucose
• normal BMI

Exclusion criteria

• smokers
• vegetarians
• subjects who receives any drug treatment
• lactose malabsorption