Does Gut Health = Brain Health?

Good diet good for brain health

June 28, 2023

Could changing your diet play a role in slowing or even preventing the onset of Alzheimer’s disease? We’re one step closer to finding out, thanks to a new study that provided new evidence about the link between gut health and brain health.

The analysis, led by a team of researchers at the University of Nevada, Las Vegas, looked at the gut microbiome, the trillions of bacteria, viruses, fungi and other microorganisms that live in our gastrointestinal tracts. A rich mix of “good” gut microbes promotes sound health, helping to digest food and unlock nutrients. A healthy gut microbiome also supports the body’s immune system and produces chemicals that bolster brain health, working through an intricate network of cells and proteins that comprise the gut-brain axis.

Normally, between 500 and 1,000 species of bacteria exist in the human gut at any one time. But a poor diet, aging, genetics and other factors can disrupt the balance of these and other microbes, setting the stage for poor health, including possibly Alzheimer’s disease.

For the current study, published in the Nature journal Scientific Reports, researchers examined data from dozens of past studies into the belly-brain connection. They identified six specific types of gut bacteria that were associated with protection against the likelihood of developing Alzheimer’s, and four specific types associated with an increased the risk of developing the disease. Having more or less of these specific types of bacteria, the researchers report, may interact with genes like APOE to increase or decrease your risk of developing Alzheimer’s disease.

“Most of the microorganisms in our intestines are considered good bacteria that promote health, but an imbalance of those bacteria can be toxic to a person’s immune system and linked to various diseases, such as depression, heart disease, cancer and Alzheimer’s disease,” said study author Jingchun Chen. 

The findings add to growing evidence linking the gut microbiome to the risk of Alzheimer’s disease. Eating a high-fiber diet, for example, is known to promote the health of the gut microbiome, and a fiber-rich diet is also associated with a decreased risk of developing Alzheimer’s disease. A Mediterranean-style diet, rich in whole grains, vegetables, fish and heart-healthy fats like olive oil, can likewise alter the makeup of the gut microbiome and is also known to lower the risk of Alzheimer’s disease. Regular exercise and sound sleep can also bolster the health of the gut microbiome and are similarly linked to a decreased risk of Alzheimer’s disease.

High-fat, high-sugar diets, or consumption of lots of highly processed foods, on the other hand, can alter the gut microbiome and disrupt the gut-brain axis, possibly increasing the risk of Alzheimer’s disease, other research suggests. Long-term use of laxatives, which can disrupt the gut microbiome, is similarly linked to an increased risk of developing Alzheimer’s disease.

Scientists continue to learn more about the gut microbiome and its role in health and illness, including Alzheimer’s disease. One day, doctors may be able to prescribe medications or personalized diets to promote gut health, and by extension brain health. In the meantime, strive for a heart-healthy diet rich in whole grains and unprocessed foods. It may help you live a longer life, with your cognitive abilities intact.

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.

Source: Davis Cammann, Yimei Lu, Melika J. Commings, et al: “Genetic correlations between Alzheimer’s disease and gut microbiome genera.” Scientific Reports, March 31, 2023


Alzheimer's Articles