Major milk proteins - casein and whey proteins - are high-quality proteins with unique insulinotropic property that do not increase postprandial blood glucose upon administration. It is believed that these proteins increase insulin secretion by both a direct effect of particulary branched chain amino acids on ß-cell of islets of Langerhans in pancreas and also by activation of incretin hormones.
However, due to a different amino acid profile and digestion, whey proteins achieve higher insulinotropic effect in comparison with casein proteins.