Intestinal Bacteria and the Gut-Brain Axis
Dysbiosis and the Development of Disease
The gut-brain axis is a complex system of communication between the gut and brain that is greatly influenced by an individual’s intestinal bacteria, also known as microbiota. Evidence indicates that the quantity and quality of a person’s microbiota has a direct effect on bowel function and mental health. Recent research is uncovering previously unknown links between microbiota imbalances (dysbiosis) and the development of conditions like irritable bowel syndrome, depression, autism, and even the diseases of Alzheimer’s and Parkinson’s.
The gut is a complicated organ intricately tied to the enteric nervous systems. Known as the body’s “second brain,” the enteric nervous system consists of a mesh of more than 100 million neurons embedded in the gastrointestinal tract from the esophagus to the anus. A main branch of the autonomic nervous system, the enteric nervous system can act independently or in concert with its sister branches, the sympathetic and parasympathetic systems, in communicating to and from the central nervous system (brain and spinal cord) along the gut-brain axis.
Both clinical and experimental research shows that gastrointestinal microbiota plays an important role in the gut-brain axis crosstalk, by assisting in the digestion and synthesis of nutrients, maintaining intestinal integrity and immunity, facilitating fecal transit, and in the production of neurotransmitters. Although tens of trillions of different microorganisms make up intestinal microbiota, each individual’s microbiota profile is distinct.
While researchers are still uncovering the exact mechanisms between intestinal microbiota and the gut-brain axis, there is clear evidence that imbalances in gut microbiota play a role in the development of health disorders, including those related to mood and cognition. Strong evidence suggests that intestinal microbiota interacts with the gut-brain axis by regulating brain chemistry and influencing neurotransmitter and hormonal responses to stress, anxiety and memory function. Macrobiotic dysbiosis can be caused by a number of factors including, destruction of bacterial habitat by overuse of antibiotics, invading strains of foreign bacteria, poor diet, and chronic stress.
Whatever the causes of the macrobiotic dysbiosis, there may be a therapeutic role for strain-specific probiotics in treating certain health disorders and diseases. Moreover, the regular consumption of foods rich in beneficial bacteria, like yogurt, kefir, miso, sauerkraut, kimchi, kombucha, and natto, may assist in maintaining health and function of the gut-brain axis, and in preventing the development of disease.
