Too sterile. It is believed that the dysfunction of the intestinal epithelium is favored by excess sterility – strong disinfectants commonly used in toilets and in the kitchen sterilize the environment from bacteria, including the “good” ones. Disturbances in the intestinal barrier can also occur as a result of shock, burns, chronic inflammation, intestinal infections, autoimmune and metabolic diseases, and obesity. Anything that disrupts microbiome homeostasis can affect the integrity of the blood-brain barrier.
And this barrier, created by tight connections between endothelial cells in blood vessels, is extremely selective – it prevents unwanted molecules and cells from entering the brain. Scientists point out that the transport of molecules across the blood-brain barrier can be modified by bacteria in the gut, so they play an important role in protecting the brain. It is already known that the microbes can influence the occurrence of depression, anxiety, chronic headaches, short-term memory disorders, schizophrenia, autism, Alzheimer’s disease or Parkinson’s disease.
Researchers also observed that short-chain fatty acids act as a signal between the gut flora and the microglia in the brain. Short chain fatty acids are the product of bacterial fermentation of fiber, dairy products and other food products. They can travel to the brain through the bloodstream, where they help the microglial cells find any inflammatory responses quickly and efficiently.