Probiotics may help slow age-related cognitive decline, study finds

A new study suggests that taking a probiotic could help prevent the decline in memory and thinking that can accompany aging. The research, which was presented at the annual meeting of the American Society for Nutrition, found that when study participants with mild cognitive impairment received the probiotic Lactobacillus rhamnosus GG (LGG) for three months, their cognitive scores increased. This cognitive improvement was also associated with changes in their gut microbiome.

For study participants who had mild cognitive impairment and took the probiotic Lactobacillus rhamnosus GG (LGG) for three months, cognitive scores increased. This cognitive improvement was also associated with changes in their gut microbiome. Credit: Mashael Aljumaah, University of North Carolina at Chapel Hill and North Carolina State University

The researchers believe that these findings could pave the way for new, non-invasive treatments that leverage the gut microbiome to mitigate cognitive decline in the aging population.

"The implication of this finding is quite exciting, as it means that modifying the gut microbiome through probiotics could potentially be a strategy to improve cognitive performance, particularly in individuals with mild cognitive impairment," said Mashael Aljumaah, a microbiology doctoral candidate at the University of North Carolina at Chapel Hill and North Carolina State University. "This adds a new layer to our understanding of the microbiome brain-gut connection and opens up new avenues for combating cognitive decline associated with aging."

The study involved 169 participants between 52 and 75 years old who were divided into two groups depending on whether they had no neurological issues or mild cognitive impairment. Within each group, participants either received the LGG probiotic or a placebo in a double-blind, randomized clinical trial lasting three months.

The analysis revealed that microbes in the genus Prevotella were present in a higher relative abundance in participants with mild cognitive impairment than those with no cognitive impairment. This suggests that gut microbiome composition could serve as an early indicator for mild cognitive impairment, offering opportunities for earlier interventions to slow cognitive decline.

For study participants who had mild cognitive impairment and received the LGG probiotics, the Prevotella relative abundance decreased. This change coincided with improved cognitive scores, suggesting that cognitive health in older adults could be improved by manipulating the gut microbiota.

"By identifying specific shifts in the gut microbiome associated with mild cognitive impairment, we're exploring a new frontier in preventive strategies in cognitive health," said Aljumaah. "If these findings are replicated in future studies, it suggests the feasibility of using gut microbiome-targeted strategies as a novel approach to support cognitive health."

The researchers are now working to understand the specific mechanisms of how microbes like Prevotella influence the gut in a way that improves brain health. Specifically, they are exploring how certain molecules produced by these bacteria modulate the functionality of neuroprotective hormones that can cross the blood-brain barrier.

These findings are still preliminary, but they offer a promising new avenue for research into the prevention and treatment of cognitive decline. If further studies confirm these findings, probiotics could become a new standard of care for people who are at risk of developing cognitive impairment.