Hippocrates said, "All disease begins in the gut." Research has revealed that gut health is critical to overall health, and an unhealthy gut contributes to a wide range of diseases and associated symptoms. Two variables that are closely related that determine our gut health are the intestinal gut flora and the gut barrier. The role of intestinal gut flora or "microbiome" in human health and disease has been well studied and shown to promote normal gastrointestinal function, regulate metabolism, provide protection against infection by comprising 80 percent of our immune system and support a healthy gut barrier.

The gut barrier is a protective layer of epithelial cells lining the intestines that are connected by tight junctions. This gatekeeper selectively determines what gets into the body and what stays out. When this barrier becomes permeable (leaky) due to disruption of the junctions and tissue destruction, molecules can escape into the bloodstream where the body may mount an immune response and attack them. These attacks play a role in the development of inflammation and autoimmunity, and can contribute to disease in many organs, especially the brain.

Inflammation in the gut may contribute to inflammation in the brain and vice-versa. Problems in the gut like infection or inflammation can lead to a higher risk of problems associated with a leaky brain such as dementia, neurological conditions, depression, or anxiety. There is likely some contribution to this problem through the vagus nerve due to poor vagal tone. The vagus nerve establishes one of the connections between the brain and the gastrointestinal tract and sends information about the state of the inner organs to the brain via its afferent fibers.

Some known contributors to leaky gut and leaky brain include consuming inflammatory foods that are genetically modified or contain gluten; toxic exposure to herbicides and pesticides; artificial ingredients in food such as sweeteners or flavorings; highly processed diets of refined sugar, industrialized seed oils and high fructose corn syrup; disruption of the gut flora by medications like antibiotics and nonsteroidal anti-inflammatory drugs; a low-fiber diet; food sensitivity; high stress; poor sleep; and physical inactivity.

Phyllis Gee, M.D., is the owner of Willowbend Health & Wellness Integrative Functional Medicine.