GABA (g-aminobutyric acid) An amino acid widely occurring in nature, is now attracting attention for its effect in suppression of blood pressure elevation and its tranquilizing action.

GABA is attracting attention for its effect in suppression of blood pressure elevation and its tranquilizing action. Rice germ-derived materials rich in GABA have been developed.

GABA (g-aminobutyric acid) is a naturally occurring amino acid widely distributed in nature from invertebrates to vertebrates, and then to plants. GABA is attracting attention for its effect in lowering blood pressure and its tranquilizing action. It was first discovered in an extracted mammal brain in 1950. Since then, it has been found highly concentrated in the encephalon and medulla oblongata, functioning as an inhibitory nerve transmitter and useful in stimulating blood circulation in the brain.

In Japan, Tsushida et al. of the former MAFF National Research Institute of Tea (currently the National Institute of Vegetables and Tea Science) began developing GABA-rich tea in 1984 and successfully produced a new type tea in which almost all glutamic acid has been converted to GABA without changing the content of catechin or caffeine through six to ten hours of nitrogen gas treatment.

Mori and Horino et al. at the MAFF Chugoku National Agricultural Experiment Station addressed the issue of GABA production from rice bran (containing rice germ) from about 1994, leading to the development of GABA-rich materials derived from rice germ. Subsequent development of food materials with enhanced physiological activity by adding GABA has been advanced. GABA has been applied to tea, rice, and then health foods.

The physiological actions of GABA thus far reported include improved cerebral blood circulation, the suppression of blood pressure elevation, tranquilization, activated renal and hepatic functions, stimulated alcohol metabolism, and deodorization. Inhibitory action regarding colon cancer is also expected.