Abstract
A study was conducted to examine the effects of simultaneous ingestion of protein and carbohydrate on plasma levels of glucose, insulin and free amino acids in 11 healthy women. The levels of plasma glucose, insulin and free amino acids were assayed at 30 and 150min after ingestion of rice, eggs and rice+eggs, respectively. The quantity of rice and eggs corresponded to an energy value of 50g of carbohydrate. 1) Plasma glucose and insulin levels at 30min after ingestion: The increase in the level of plasma glucose after ingestion of rice alone was suppressed significantly (p<0.01) by simultaneous ingestion of eggs. However, the increase in the level of insulin induced by rice was not affected by simultaneous ingestion of eggs. 2) Plasma free amino acid levels at 150min after ingestion: Upon ingestion of rice+eggs, the plasma levels of most amino acids increased significantly, as was the case for eggs alone. Consequently, we examined whether the difference in the increase of each amino acid between eggs alone and rice+eggs was significant. The increase induced by rice+eggs was significantly less marked than that induced by eggs alone for V, L and I (p<0.05 for V, p<0.01 for L and I). Therefore, we conclude that the increase of plasma branched chain amino acids induced by ingestion of protein is suppressed by simultaneous ingestion of carbohydrate.
