Gut microbiome changes may help reverse age-related memory loss: study
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Remotely altering the composition of the gut microbiome by stimulating the vagus nerve may help reverse age-related memory loss, according to a new study.
The vagus nerve carries signals from the gut to the brain, and researchers say modifying its activity could influence memory function. The study adds to growing research exploring the gut as a potential target for addressing health issues linked to ageing.
Senior author Christoph Thaiss, assistant professor of pathology at Stanford University, said the research aimed to understand why some people remain cognitively sharp even at an advanced age while others experience memory decline starting in their 50s or 60s.
He said the findings suggest the timeline of memory decline is not fixed but is actively influenced by processes in the body, with the gastrointestinal tract playing a critical role.
The study, conducted in mice and published in the journal Nature, found that the composition of the gut microbiome changes with age, favouring certain bacterial species over others.
Researchers said immune cells in the gastrointestinal tract detect these changes and trigger an inflammatory response. This inflammation interferes with the ability of the vagus nerve to send signals to the Hippocampus, a brain region involved in memory formation and navigation.
When researchers stimulated the vagus nerve in older mice, the animals showed significant improvement in memory and problem-solving tasks, performing similarly to younger mice.
Co-author Maayan Levy said the findings demonstrate that brain processes can be influenced through interventions outside the brain. Because the gastrointestinal tract can be easily accessed, adjusting gut microbiome-related metabolites could offer a promising approach to regulating brain function.
The study also identified increased levels of the bacterium Parabacteroides goldsteinii in ageing mice, which was associated with cognitive decline and higher levels of metabolites called medium-chain fatty acids that trigger inflammation. Researchers said this inflammation suppresses vagus nerve activity, reduces hippocampal function, and impairs the ability to form lasting memories.