A recent story by Rob Stein from NPR describes the relationship between gut flora, brain activity, and psychiatric symptoms. The implication is that someday we may be able to treat brain disorders such as autism, bipolarism, anxiety, and depression with probiotics. This is one of the most fascinating stories I’ve read for quite a while.
When we think of serotonin we think of the neurotransmitter in the brain that regulates mood, anxiety, etc… Selective Serotonin Re-uptake Inhibitors, SSRI’s, are used to treat anxiety and depression. But it turns out that >90% of our body’s serotonin is found in the gut. The enteric nervous system (ENS) of the gut is referred to as the second brain. The relationship between the gut and brain is complicated. Gut flora and serotonin both play a role in inflammatory bowel diseases. Current research now suggests that there is also a relationship between our gut flora and our brain function, moods, anxiety, and possibly certain psychological disorders such autism and bipolarism.
There’s no doubt that our ENS is really important for a lot of things, including regulating inflammatory conditions within the gut, possibly controlling our moods, and even regulating bone metabolism. For example, serotonin may play a key role in the development (or not) of osteoporosis. While we don’t yet know which cocktail or cocktails of bugs will to do the real magic, perhaps one day we’ll have probiotics with different cocktails of microbes to treat a variety of different diseases.
Tillisch K, Labus J, Kilpatrick L, Jiang Z, Stains J, Ebrat B, Guyonnet D, Legrain-Raspaud S, Trotin B, Naliboff B, Mayer EA. 2013. Consumption of fermented milk product with probiotic modulates brain activity. Gastroenterology 144(7):1394-401.
Bercik P, Denou E, Collins J, Jackson W, Lu J, Jury J, Deng Y, Blennerhassett P, Macri J, McCoy KD, Verdu EF, Collins SM. 2011. The intestinal microbiota affect central levels of brain-derived neurotropic factor and behavior in mice. Gastroenterology 141(2):599-609.