γ-Aminobutyric acid (GABA) , a nonprotein amino acid, possesses well-known physiological functions such as neurotransmission, induction of hypotension, and diuretic and tranquilizer effects. Recently, GABA has been recognized as a strong secretagogue of insulin from the pancreas, which may prevent symptoms of diabetes. Because of these physiological effects, several functional foods incorporating GABA have been manufactured.