γ-Aminobutyric Acid-producing Lactic Acid Bacteria from Kimchi : Potential Psychobiotics

γ-Aminobutyric acid (GABA) functions as the primary inhibitory neurotransmitter in mammals, numerous studies have demonstrated that direct ingestion of GABA effectively induces natural sleep and alleviates stress. Low doses of GABA reduce stress by modulating the autonomic nervous system, while high doses do so by modulating the central nervous system. The oral administration of GABA-producing lactic acid bacteria (LAB) to experimental animals has been shown to promote mental health and ameliorate neurological disorders, such as essential tremor and depression, and to have positive effects on diabetes, fibromyalgia, chronic fatigue, and pain in experimental animals. Consequently, diet supplementation with GABA-producing LAB offers a potential means of treating mental health and neurological disorders in humans. Furthermore, supplementation with GABA-producing LAB might have sleep-inducing and stress-relieving effects akin to those observed after GABA consumption. Numerous LAB strains in kimchi produce diverse metabolites, and a significant proportion generate GABA. Although further animal and clinical studies are required, kimchi-sourced GABA-producing LAB appear to be potential psychobiotics.