The organ whose health slows brain aging has been named

An international team of researchers has concluded that changes in the gut microbiome may slow cognitive decline in older adults. The study has been published in the journal Nutrition Research (NR).

The scientists analyzed 15 studies conducted between 2012 and 2025, involving 4,275 people over the age of 45 from Europe, Asia, North America, and the Middle East. Participants had dementia, mild cognitive impairment, or an elevated risk of developing these conditions. The studies employed various approaches to "modulating" the gut microbiota: from diets (Mediterranean, ketogenic, omega-3 supplementation) to probiotics, prebiotics, and even fecal microbiota transplantation.

Overall, participants who received such interventions showed an increase in gut bacterial diversity. This was accompanied by improvements in memory, executive functions, and overall cognitive ability. The most pronounced effect was observed in the early stages of impairment, while in advanced Alzheimer's disease the impact was limited.

According to the authors, the positive effect may be linked to bacterial metabolites — for example, short-chain fatty acids, which possess anti-inflammatory and neuroprotective properties.

One of the most notable yet still experimental methods turned out to be microbiota transplantation. In one of the studies, patients with Alzheimer's disease demonstrated improvements in memory and attention scores after the procedure, as well as a richer composition of gut microflora.

However, such interventions remain poorly studied in terms of safety and long-term effects.

More accessible methods — diet and dietary supplements — showed more moderate but consistent results. In particular, the Mediterranean diet with olive oil and nuts was associated with better cognitive outcomes. Prebiotics and probiotics also demonstrated improvements in memory and verbal functions in small randomized trials.

The authors emphasize that the available data are still preliminary and require confirmation in long-term clinical trials. Nevertheless, the results point to an important role of the "gut-brain" axis and open up prospects for new approaches to dementia prevention.

In the researchers' view, in the future, targeting the microbiome could become part of a comprehensive strategy for maintaining cognitive health and slowing brain aging.