Does bacteria indicate that Alzheimer’s disease is imminent?

In the end everything is erased: himself, all memories, an entire life. More than 400,000 people in Germany develop Alzheimer’s dementia each year. The insidious process of destroying many neurons in the brain usually begins in middle age, and may take about 20 years before the first symptoms such as forgetfulness, confusion, and speech disturbances appear. Deposits of proteins such as beta-amyloid and tau fibers in the brain, and immune cells and inflammatory processes are involved in these processes. According to the latest research findings, the gut and the many bacteria that live in it, the intestinal microbiome, also play an important role.

The brain and intestines have been working together for a long time. “For hundreds of thousands of years, the human body has lived in a kind of symbiosis with intestinal bacteria,” says neurologist Thorsten Bartsch of the University Hospital Schleswig-Holstein in Kiel, who researches the gut-brain axis in Alzheimer’s disease. The gut has its own nervous system, the “gut brain,” which is connected to the nervous system in the brain via the vagus nerve. Intestinal bacteria process the leftovers you get. This results in products of metabolism reaching the brain directly through the intestinal wall and bloodstream or indirectly affecting the vagus nerve, the highway to the brain.