Gut microbiota refer to the microorganisms inhabiting the intestinal tract and living in symbiosis with the host. There are trillions of microbes involved: mostly bacteria and also viruses and fungi [Citation1]. They influence metabolism and immune regulation, affecting mental function. Healthy gut microbiota is associated with more normal central nervous system action. However, a dysfunctional biota or dysbiosis can induce inflammation in the brain, yielding psychopathology, such as anxiety or depression; the microbiota mediate this bidirectional communication between gut and brain [Citation2].
Gut microbiota are established at birth by maternal transmission and later via exposure to environmental microbes. The composition of the flora changes over time. The gut of infants is dominated by the bacterial genera Bifidobacterium and Lactobacillus [Citation3]. Healthy adult intestines predominantly include firmicutes and bacteroidetes [Citation1]. Dysbiosis occurs because of improper or changed diet and other factors, like ingestion of antibiotic drugs.
Research with germ-free mice and human probiotic trials further support the role for gut microbiota in psychopathology and in intestinal conditions, like irritable bowel syndrome or inflammatory bowel diseases [Citation4]. Germ-free mice exhibit excessive responses to stress for unknown reasons [Citation5]. Yet, there are influential circulating inflammatory mediators such as cytokines, lipopolysaccharides, and neuroactive metabolites like gamma-aminobutyric acid or 5-hydorxytroptophan [Citation5]. There are neuroendocrine pathways between the gut and brain that regulate function, called the gut–brain axis. [Citation2]
There are ongoing research and clinical trials in the field of intestinal microbiota. Manipulating gut flora by administering probiotics might assist in the management of metabolic syndrome and prevent the emergence of diabetes in prediabetics Citation6]. There is a potential link between gut microbial composition and the onset of eczema in infants [Citation7]. A mice-model trial administered a mixture of phylogenetically diverse intestinal microbiota to minimize intestinal dysbiosis caused by Clostridium difficile infection [Citation8]. Thus, therapeutic gut microbial manipulation has the potential to be a treatment for people suffering from C. difficile colitis, a leading hospital-acquired infection in the United States [Citation8,Citation9].
Much of our understanding of microbiota comes from animal studies. A diet rich in plant-based products and fermented foods and a high-fiber intake with low fat content might foster a microbiome with positive effects on health. Diet therapy, probiotics, and/or fecal microbiota transplants might be potential treatments for patients with psychopathology, functional gastrointestinal disorders, metabolic syndrome, obesity, and/or C. difficile infections.
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References
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- Centers of Disease Control and Prevention. Nearly half a million Americans suffer from C. difficile infections in single year. [Cited 2019 Aug 18]. Available from: https://www.cdc.gov/hai/dpks/deadly-diarrhea/dpk-deadly-diarrhea.html.