Diets rich in Mediterranean components may lower the risk of dementia.

In a groundbreaking long-term study, researchers from leading universities and medical research institutes specialising in neurology and nutrition have explored the impact of the Mediterranean diet on dementia and cognitive functions, particularly in individuals with a high genetic risk.

The Mediterranean diet, rich in fruits, vegetables, nuts, whole grains, olive oil, and moderate amounts of fish and poultry, while limiting processed foods and red meat, appears to play a significant role in shaping brain outcomes, even for those with the strongest inherited risks.

Scientists caution that this type of research cannot prove cause and effect because it is based on observation, not direct intervention. However, the strength of the findings and the size of the study make it clear that genetics do not tell the whole story.

The study, which followed thousands of men and women over several decades, considered their eating patterns, genetic profiles, and blood chemistry. Blood samples were analysed to measure hundreds of metabolites, compounds that act like fingerprints of what is happening inside the body.

Among those with the highest genetic risk, those who stuck to the Mediterranean eating pattern showed fewer signs of memory decline over time. This could be due to the presence of protective compounds tied to the Mediterranean diet, such as healthy fats and plant-based molecules that help combat stress in the body.

Adding metabolite information to standard health data improves predictions of who would develop dementia better than family history alone. Among the intriguing findings was higher levels of a caffeine byproduct in the blood of high-risk individuals who followed the Mediterranean diet, which is thought to have antioxidant effects.

On the other hand, those who carried risky genes and ignored diet quality tended to have more harmful compounds in their blood. Harmful compounds in the blood of those with poor diet quality include forms of fat linked to inflammation and poor clearance of brain waste products.

While no single habit can erase genetic risk, the right choices may tilt the odds in a better direction and help preserve memory longer. Focusing on a balanced diet rich in plants, healthy fats, and whole foods remains one of the most practical steps for supporting brain health.

The study focused on the APOE4 gene, a strong risk marker for Alzheimer's disease, but also investigated other genes involved in brain tissue repair and metabolism. The study suggests that diet may influence how genes behave by changing the chemical environment in the body.

This does not mean blood tests can fully predict brain health yet, but hints at a future where doctors may combine genetic and chemical clues to give more personalised advice. Dementia, including Alzheimer's disease and related conditions, is a significant health issue, with another person being diagnosed every few seconds worldwide.