Research Suggests Gut Microbiome Impacts Brain Health, Dementia Risk

New research from Baycrest Foundation suggests that the gut microbiome plays a role in how diet and exercise affect brain health and dementia risk. The findings could help experts optimize strategies to prevent dementia, according to the study authors.

Lifestyle interventions to reduce risk of dementia often include diet and exercise, which in turn affect the gut microbiome.

“We know that imbalances in the microbiome are associated with impaired cognition,” said lead author Noah Koblinsky, an exercise physiologist and project coordinator at Baycrest’s Rotman Research Institute (RRI), in a press release. “However, we don’t know much about the role of the microbiome when we use lifestyle interventions, such as diet and exercise, to support brain health. Can we tailor lifestyle interventions to specifically target the gut microbiome, and will this help to optimize their effects on cognition? In this review study, we aimed to address this gap in knowledge.”

The team reviewed any existing research on diet and exercise interventions that looked at both the microbiome and brain health and published their findings in Journal of Gerontology: Series A. According to the study, the gut microbiome does appear to play a role in how diet and exercise affect brain health, although more research is needed to understand exactly how.

Studies have shown that diets have a significant impact on the microbiome, with a Mediterranean-style diet appearing to have the greatest benefit to a healthy gut microbiome and brain, according to the study. For example, one study with 1200 older adults asked half the participants to follow a Mediterranean-style diet for 12 months, while the other half did not follow this diet. Those in the Mediterranean diet group showed significant improvements in cognition and had healthier microbiomes associated with better brain health.

In another study, investigators used antibiotics to “kill off” the gut microbiome in a sample of rats. They then gave the rats microbiome transplants from rats that had either been fed an unhealthy diet or a healthy diet. According to the study, the researchers found that the rats in the unhealthy diet group showed worse memory performance, as well as inflammation in the intestines and brain.

These findings support the idea that the microbiome plays a role in the way diet impacts brain health. The team found fewer studies examining exercise, but the studies that did suggest that starting exercise, specifically aerobic exercise, can lead to changes in the gut microbiome and brain health at the same time.

After this review of existing research, the team is now launching a randomized controlled trial focused on diet and exercise and are looking to secure funding to include analysis of microbiome changes.

“By better understanding how changes to the gut microbiome affect the relationship between lifestyle and brain health, we can strengthen existing lifestyle interventions and create new strategies to reduce dementia risk, helping older adults everywhere age fearlessly,” said senior author Nicole Anderson, PhD, senior scientist at the RRI, in the press release.

REFERENCE

Research suggests gut microbiome plays a role in lifestyle’s effects on dementia risk. News release. Baycrest; October 11, 2022. Accessed October 26, 2022. https://www.baycrest.org/Baycrest-Pages/News-Media/News/Research/Research-suggests-gut-microbiome-plays-a-role