It’s well known that gut health can impact many aspects of health. A 24-week clinical trial found that taking daily probiotics was linked to better results on some cognitive tests. The supplement takers also had a significant reduction in a biomarker linked to Alzheimer’s. All the participants in the study were older and had early cognitive impairment.
The South Korean study started with 100 participants, but had 87 people by the end of the 24 weeks. Out of those, 40 took probiotics for 24 weeks, and 47 took a placebo. After 24 weeks, people taking the probiotics had significantly better scores on the Clinical Dementia Rating scale. They also improved at interpreting visual information, spatial organization and drawing complex figures.
“Collectively,” the trial authors wrote, “these findings indicate that maintaining or restoring the gut microbial balance through probiotic supplementation may represent a promising strategy to mitigate early Alzheimer’s disease-related pathological processes during the prodromal stage of Alzheimer’s.”
The probiotics had modest impact on inflammatory markers. However, the probiotic group did have significantly lower levels of one biomarker of inflammation. Other studies have sown that gut health impacts inflammation. If poor gut health weakens the blood-brain barrier it can contribute to stress on the brain.
Another study, from Cardiff Univ. and Imperial College London, found that gut bacteria may be used to spot people with mild cognitive impairment and predict the speed of people’s mental decline. The research used fecal samples from 35 adults, mostly cohabiting couples where one person had mild cognitive impairment and their partner didn’t.
The researchers found that the people with cognitive impairment had different gut bacteria from the people without it. After following the participants for a year, the researchers saw that having higher levels of some bacteria and chemicals in the gut was linked to faster decline. It’s possible that this could be a key to predicting future mental decline.
“Mild cognitive impairment affects around one in four older adults worldwide, but we have no simple way of telling who will go on to decline quickly. This was a small study and the findings need confirming in larger groups, but they point towards simple, non-invasive tests that could one day support earlier diagnosis,” said study co-author Dr. You Zhou, of Cardiff Univ.
“Gut bacteria and chemicals are increasingly recognized as an important link between the gut and the brain,” said co-author Prof. Julian Marchesi, of Imperial College London. “By looking at both together, we get a much fuller picture of what’s changing in people with mild cognitive impairment. Future studies on larger groups of patients will help pinpoint exactly which microbes and chemicals matter most.”
