A new study presented at the International Stroke Conference and published online in the Scientific Reports journal has found a correlation between dementia and gut bacteria – finding that the depletion of certain gut bacteria results in an increased risk of the disease.
Learn more about the study and what it means for the future of dementia research.
Dementia and Gut Bacteria
The study involved 128 outpatients visiting a memory care clinic. Researchers accounted for demographics, including other dementia risk factors, and used MRI brain scans and neuropsychological tests to assess cognitive function. To determine gut microbiota (organisms that live in the digestive tract and account for about a thousand different species of bacteria), researchers used fecal samples.
Study participants were divided into people with and without the disease. Their analysis revealed differences in components of gut microbiota between the two groups. For the group with dementia, levels of bactericides (enterotype I) was decreased compared to the group without dementia. Meanwhile, other bacteria types (enterotype II) were increased in the group with dementia. The fecal samples also revealed higher concentrations of ammonia, indole, phenol and skatole, in the group with dementia.
“Although our study has numerous limitations, the results suggest that the gut microbiome could be a new target for the management of dementia,” study author Naoki Saji, MD, Ph.D., vice director of the Center for Comprehensive Care and Research on Memory Disorders, National Center for Geriatrics and Gerontology in Japan, says.
Strong Evidence of Link Between the Two
While the study was unable to prove a causal relationship and had a small sample size, researchers believe the odds ratios in the study were high, suggesting an underlying mechanism in the effects of gut microbial composition on brain health.
Costantino Iadecola, MD, professor of neurology at Weill Cornell Medical College and director of the Feil Family Brain and Mind Research Institute in New York City, remarked, “It’s difficult for studies in this field to draw correlations. The microbiota is variable and it can be modified by a wide variety of factors….”
Acknowledging its limitations, the study still supports previous data linking brain health and diet. Some researchers believe a Mediterranean diet rich in fish, fruits and vegetables may be beneficial while others promote a traditional Japanese diet. Most agree that processed foods and sugars have a negative impact on brain health.
Have you seen a correlation between dementia and gut bacteria in your life? We’d like to hear your stories in the comments below.
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