There's a New Link Between Gut Health and Alzheimer's Disease

WIRED 

Researchers found that a metabolite produced by gut bacteria can weaken the barrier that protects the brain and promote changes associated with the cognitive disease. For years, scientists have known that the gut microbiome of people with Alzheimer's differs from that of healthy people. What remains unclear is whether these differences are a consequence of the disease, contribute to it, or simply accompany it. It is possible that part of the puzzle lies not in the gut bacteria themselves but in the molecules they produce, which end up circulating throughout the body. A team of scientists believes it has found one such molecule.