Gamma-aminobutyric acid (GABA)—a type of amino acid the brain makes naturally—helped people relax, reduced anxiety and increased immune strength in two new studies.
In a brain-wave study, researchers recruited 13 participants who took water, GABA or the amino acid L-theanine. After waiting 60 minutes, using electroencephalography (EEG), doctors attached electrodes to the scalp to detect electrical wave activity in the brain. Compared to water only or L-theanine, GABA increased alpha brain waves, which occur when people are not aroused, are resting or meditating, and decreased beta brain waves, which occur when people are aroused, actively engaged or hyperactive.
In an immune system study, researchers recruited eight people who were afraid of heights and who took GABA or a placebo before walking across a narrow bridge suspended 150 feet above a canyon to induce stress. Halfway across the bridge, researchers measured blood pressure and an immune antibody (saliva Immunoglobulin A or sIgA), which protects the body from microbes and infection. Under stress, the body typically produces less sIgA, but participants who had taken GABA had normal sIgA levels midway across the bridge and higher levels after crossing the bridge, while the placebo group had significantly lower sIgA levels.
Doctors believe that GABA discourages seizures and encourages relaxation and sleep by reducing nerve cell activity. Prescription drugs for insomnia and epilepsy increase GABA activity, but have many side effects including addiction. Yale University School of Medicine in New Haven, Connecticut, recently reported that GABA levels are typically lower in clinical or major depression. The typical dosage range for GABA is 100 mg to a maximum of 1,200 mg per day in divided doses.