Thus, for example, Lactobacillus rhamnosus, usually to be found in commercially prepared Kefir, produces substantial quantities of the mammalian neuroinhibitor, gamma amino butyric acid, or GABA, with reportedly significant psychoactive effects. That chemicals produced by gut microorganisms have a sedative effect is not entirely surprising since emotion is a matter nor only of the head but of the heart, which term should be understood to include the gut where, as acknowledged in common speech, emotion is registered.
Anecdotal reports suggest that Kefir can be effective in the treatment of dermatitis, food allergies and some chronic gut-related disabilities including colitis and Krohn's disease. The cost of experiment by those so afflicted is slight, and the downside seemingly small, since the transformation of the gut flora achieved through the use of probiotics such as kefir seems to depend on continued consumption and is thus easily terminated if no benefit is experienced.
Gut Pathog. 2011; 3: 1
Acne vulgaris, probiotics and the gut-brain-skin axis - back to the future?
CanSpeccy: Guts and Gaba, Bugs and Brains, Allergies and Anxiety