Scientists named the organ capable of slowing brain aging

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 individuals over the age of 45 from Europe, Asia, North America, and the Middle East. The 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, and omega-3 supplementation — to probiotics, prebiotics, and even fecal microbiota transplantation.

The results were encouraging. Participants who received such interventions showed a notable increase in gut bacterial diversity. At the same time, improvements were observed in memory, executive functions, and overall cognitive ability. The most pronounced effects were seen specifically in the early stages of impairment — in advanced Alzheimer's disease, the impact remained limited.

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

One of the most impressive 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. Nevertheless, such interventions remain poorly studied in terms of safety and long-term consequences.

More accessible methods — diet and dietary supplements — showed 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 in nature and require confirmation in large-scale, long-term clinical trials. However, the findings point to the crucial role of the gut–brain axis and open up prospects for fundamentally new approaches to dementia prevention.

In the researchers' view, targeted manipulation of the microbiome may in the future become a fully integrated component of a comprehensive strategy for maintaining cognitive health and slowing brain aging.