Scientists study the link between the gut and Alzheimer’s disease | Alzheimer's Prevention Registry

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July 22, 2020

Scientists study the link between the gut and Alzheimer’s disease

By Alzheimer's Prevention Bulletin

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Do you know that feeling you get in your gut? It turns out your gut may really be trying to tell you something.  Our microbiome - the 100 trillion bacteria and organisms living in our gut – appears to have a profound influence on our health and risk of disease. And early scientific studies show there may be a link between the microbiome and the brain that could impact the risk of Alzheimer’s and other brain diseases.

The microbiome is a collection of bacteria, viruses and fungi that live mostly in our intestinal system. They play an important role in digestion and the production of certain vitamins, and they support our immune system. Researchers around the world study the gut microbiome, especially those bacteria unique to individuals, to learn more about their influence on our overall health.

“Our research has found that people with Alzheimer’s disease have reduced diversity of microorganisms in their gut,” said Barbara B. Bendlin, Ph.D., Associate Professor at the University of Wisconsin-Madison School of Medicine and Public Health. “Some studies link changes in the gut microbiome to other neurologic diseases so perhaps there could be a link with Alzheimer’s disease as well.”

The University’s Bendlin Laboratory studies the interaction of factors that contribute to or protect against the development of Alzheimer’s disease. Their current studies are testing whether Alzheimer’s disease is caused, or at least influenced, by the gut microbiome. If so, this could possibly lead to new forms of treatment and prevention.

“In our latest study at the Wisconsin Alzheimer’s Disease Research Center, we compared the composition of the microbiome in people with and without Alzheimer’s disease,” said Bendlin. “The decreased diversity of gut organisms that we found in people with Alzheimer’s could be influenced by diet and medication.”  However, when Bendlin and her team studied proteins related to Alzheimer’s disease in the cerebral spinal fluid of these same participants, there seemed to be a link between the abundance of certain microbes in the gut, and brain changes related to Alzheimer’s as shown by the levels of protein in the cerebral spinal fluid. 

“The abundance of certain microbes was related to the degree of brain changes,” said Bendlin.  “This occurred even in the brains of cognitively healthy people with Alzheimer’s related proteins in their spinal fluid. This may suggest a link even before people exhibit symptoms of memory and thinking problems.”

The big question is whether the gut has an influence on the brain or the brain has an influence on the gut. While this is a young and growing area of study in Alzheimer’s disease, some studies have found abnormal proteins in the intestines of people with Parkinson’s disease.

“We are learning more every day about the gut and its relationship to our health and risk of disease,” said Bendlin. “Stay tuned for more information as these studies progress.”

To learn more about studies recruiting in your area, visit our Find a Study page.