Mediterranean diet may delay brain aging, study finds

Age-related brain atrophy, or the gradual loss of brain volume over time, is a natural part of aging that leads to cognitive decline and neurological issues. However, groundbreaking research has revealed that lifestyle changes, particularly diet, may hold the key to slowing this process.

An international team of scientists from Ben-Gurion University of the Negev, Harvard University, Leipzig University, and others have made significant strides in understanding how diet influences brain health. Their findings, published in The American Journal of Clinical Nutrition, suggest that better blood sugar control may be a powerful tool against age-related brain deterioration.

This study, part of the extensive DIRECT PLUS Brain MRI trial, focused on the biological age of the brain—distinct from chronological age—measured through brain imaging. Brain age represents the health of the brain and can sometimes deviate significantly from the actual age of an individual.

In aging, regions like the hippocampus tend to shrink, and the lateral ventricles expand, signaling a decline in cognitive function. People with healthier brains often have a “younger” brain age, while accelerated brain aging may indicate higher risks of cognitive issues.

The DIRECT PLUS trial stands as one of the most comprehensive brain MRI studies to date, involving 300 participants divided into three dietary groups. Over 18 months, each participant underwent whole-brain MRI scans, and their brain health was assessed using Hippocampal Occupancy (HOC) as a predictor of future dementia risk.

HOC, which decreases with age, served as a marker of how different diets impact brain aging. Using an advanced automated tool, NeuroQuant, the researchers analyzed the data and discovered notable improvements in participants who achieved better blood sugar control and followed specific dietary patterns.

The researchers linked reduced HbA1c levels, an indicator of blood sugar control, to positive changes in brain regions crucial for cognitive and motor functions. Specifically, lower HbA1c was associated with healthier changes in the thalamus, caudate nucleus, and cerebellum. This connection emphasizes the importance of blood sugar management in protecting brain health over time.

Building on past research, the DIRECT PLUS trial examined the effects of the Green Mediterranean (Green-Med) diet, which has already been associated with benefits like improved blood sugar control. This diet, rich in plant-based polyphenols from sources like Mankai (a high-protein aquatic plant) and green tea, limits red and processed meats. These polyphenols, the study suggests, may be especially beneficial as they cross the blood-brain barrier and reduce brain inflammation.

This is a promising finding because brain inflammation is a known contributor to cognitive decline. As Prof. Iris Shai from Ben-Gurion University explains, “Maintaining low blood sugar levels, even within the normal range, shows promise for preserving a younger brain, especially when combined with a healthy diet and regular physical activity.” She adds that the polyphenols found in these diets play a key role in reducing inflammation in the brain, which is crucial for maintaining memory and cognitive function.

Dafna Pachter, a Ph.D. student who led the research, noted the potential of diet as a strategy to slow brain aging. “This trial offers a safe approach to potentially slow down our brain aging—by adopting the components of a green-Mediterranean diet,” she said.

The DIRECT PLUS trial adds significant weight to the idea that simple dietary changes could help reduce the risk of age-related cognitive decline. This is especially valuable as age-related brain atrophy can often precede conditions like dementia and Alzheimer’s disease.

While the exact causes of age-related atrophy vary, factors such as type 2 diabetes, hypertension, high cholesterol, and inflammation are known contributors. Individuals with diabetes, in particular, face a heightened risk of structural brain changes, including hippocampal shrinkage.

Past studies have shown that people with type 2 diabetes exhibit greater structural brain abnormalities, with a higher likelihood of accelerated brain aging. This includes shrinkage of the hippocampus, a critical area for memory, and the enlargement of the lateral ventricles, both of which signal a risk of cognitive impairment. The Green-Med diet’s emphasis on blood sugar control and inflammation reduction may offer a pathway for slowing down these structural changes in the brain.

Funding for this study came from institutions including the German Research Foundation, the Israeli Ministry of Health, the Israeli Ministry of Science and Technology, and the California Walnuts Commission. However, none of these organizations influenced the study’s design, execution, or analysis, nor did they have access to the results before publication.

The Green-Med diet’s impact on brain aging was particularly evident in participants who consumed high amounts of green tea and Mankai duckweed shakes. These participants not only saw improvements in blood sugar control but also exhibited less brain shrinkage over the study period. This connection suggests that the Green-Med diet could be instrumental in promoting both metabolic and brain health.

This study marks one of the first large-scale trials to link dietary changes directly to improved glycemic control and reduced brain aging. While more research is necessary to fully understand the mechanisms involved, these results offer a hopeful avenue for preventing age-related cognitive decline through dietary adjustments. For those seeking a way to support long-term brain health, the Green-Med diet could be a beneficial approach.

Through studies like DIRECT PLUS, the scientific community continues to uncover the profound impact that diet and lifestyle have on brain health. Aging may be inevitable, but research suggests that adopting healthy dietary habits can make a difference in maintaining brain vitality.

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