This study found significant differences in the gut microbiota composition between aged “Alzheimer’s mice” and age-matched control mice. These differences included a decrease in the species called Akkermansia, which can increase gut barrier integrity and thus control how much endotoxin is released into the blood stream.

Endotoxin has been shown to cause neuroinflammation and may explain why control mice that were given a fecal transplant with gut bacteria from “Alzheimer’s mice” had amyloid beta plaque accumulation in their brains.