Effect of Low and High-Dose GABA from Unpolished Rice-Germ on Timing and Quality of Sleep: A Randomized Double-Blind Placebo-Controlled Trial

Objectives Gamma-aminobutyric acid (GABA) has potential benefits in counteracting the sleep disruption and potential therapeutic effects on blood pressure, stress, cancer, and inflammatory diseases. Recently, High-dose GABA can be extracted from fermented rice germ using lactic acid bacteria. This study aimed to evaluate the effects of GABA natural extracts from fermented rice-germ on sleep latency, subjective sleep quality and insomnia symptoms. Methods This was a prospective randomized double-blind placebo-controlled trial performed at Kyung-Hee University hospital at Gangdong from June 2013 to October 2013. Adult (age≥30) patients who was diagnosed of insomnia according to DSM-IV criteria was enrolled. They were randomized into three groups: high dose treatment group 300 mg; low-dose treatment group, 100 mg; and placebo group. Questionnaires including Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI), WHO-5 Well-Being Index were performed, and 1-week actigraphy was recorded before and 1 week after the treatment. Results Total of 114 patients were randomized into 3 groups: high-dose treatment (n=37), low-dose treatment (n=38), and placebo treatment group (n=39). At 1 week after the treatment, PSQI total score and C2 (sleep latency) score significantly decreased in low-dose and high-dose treatment group than the placebo groups [Repeated measures analysis of variance (ANOVA), p=0.017, 0.004 respectively]. ISI score also decreased in the two groups in dose-dependent manner (Repeated measures ANOVA, p=0.037). There were five (4.4%) patients who reported medication adverse events. Conclusions This study suggests that treatment of low and high-dose GABA from unpolished rice-germ decreases sleep latency and improve insomnia severity without severe adverse events. Keywords: Insomnia, GABA, Unpolished rice, Sleep quality