The human gastro-intestinal track is made of and shared by a multitude of species - a vast variety of bacteria (and other microbes) that have co-evolved with the complex ecosystem we call a human being. Measured in biomass, the human individual is 55% microbiota and 45% eukaryotic human cells.
The gut microbiome produces about 95% of the serotonin in the body. The relationship between serotonin and mood has been studied for long. Serotonin reuptake inhibitors have been effectively used in treating depression. We know now that that the gut microbiota exerts a strong influence on cognitive health and that manipulation of the microbiota could be a viable treatment option for depression, anxiety and many cognitive disorders.
We have begun to understand the relationship between gut microbiota and the brain, and we'd soon have a range of prebiotic and probiotic treatments to cure imbalances of the human microbiome.
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