Objectives Low glycemic index（GI）foods would prevent metabolic diseases. Soybean, which is categorized as low GI food, is recognized its health advantages. Recently, a nutrition bar combined soybean（Soy）has been on the market. The aims of the present study were to investigate Soy's features of GI value（test1）,“second meal effect”to glucose tolerance（test2）, and dynamics of biochemical markers after ingestion of 80 kcal of Soy as a preliminary approach for diabetes care（test3）.
Methods Healthy volunteers were recruited for each test. In the test1 and test3, glucose, insulin, triglyceride（TG：test3）, free fatty acid（FFA）, and amino acids（AA）in the blood were determined for 2-hr after ingestion of test foods. In the test2, blood glucose level was determined after ingestion of an identical meal, which was followed by 3-hr earlier test food ingestions. Soy was ingested as a test food in each test. Additionally, reference food was glucose in test1. Rice cracker（Rice）or non-meal in test2 and isoenergetic（80-kcal）wheat products in test3 were ingested for control trials.
Results GI value of Soy was 6.2±1.8. Glycemic response after identical meal in test2 was lower in Soy than in Rice and non-meal. Serum TG and FFA were not changed and plasma AAs were maintained during the 2-hr in Soy（80-kcal）.
Conclusions These findings suggested that the low GI value in Soy contributed to the“second meal effect”. Furthermore, the present study suggested that Soy has potential to an advantage for diabetes care.