Green Mediterranean diet lowers brain-aging proteins, new study finds

A new study has linked a green Mediterranean diet to slower brain aging, which involves consuming green tea and the aquatic plant Mankai.

Specific proteins were found to be associated with brain aging, but the green-Mediterranean diet decreased their levels, say researchers from Ben-Gurion University (Israel), Harvard T.H. Chan School of Public Health (US), and the University of Leipzig (Germany).

The publication in Clinical Nutrition posits that the brain-protective benefits might come from the anti-inflammatory molecules in green tea and Mankai.

Testing various diets

Harvard University notes that neurological issues, such as mild cognitive impairment and Alzheimer’s disease, are linked to a higher brain-age gap, meaning the brain is much older than the individual’s chronological age.

The study examined data from 294 participants in the Direct Plus trial. It is dubbed the “longest-running study,” looking at the brain-diet connection over 18 months. 

Participants consumed either a standard healthy diet, a green Mediterranean diet, or a traditional calorie-restricted Mediterranean diet — low in simple carbohydrates and rich in vegetables, poultry, and fish. Both groups on the Mediterranean diet also consumed a daily portion of walnuts for their antioxidants. 

Specific proteins 

After testing participants’ blood, the researchers found specific proteins — galectin-9 and decorin — that accelerated brain aging, but those from participants on the green Mediterranean diets had low levels of these proteins. 

“Studying the circulating proteins in blood allows us to observe, in a real-life setting, how the brain’s aging processes are influenced by lifestyle and dietary changes,” says study co-led, Anat Meir, postdoctoral research fellow at Harvard Chan School. 

“This approach gives us a dynamic window into brain health, helping to reveal biological changes long before symptoms may appear. By mapping these protein signatures, we gain powerful new insight into how interventions, such as diet, may help preserve cognitive function as we age.”

However, the study details several limitations. “First, the high proportion of male participants (90%) may limit the generalizability of the findings to females. Additionally, the generalizability is further restricted since the participants had either abdominal obesity or dyslipidemia.”

“Moreover, our proteomic assessment was limited to 87 proteins. In addition, this study lacks data about the participants’ educational or cognitive status.”

Mediterranean diet in headlines

A recent study suggested that people with the highest genetic risk for Alzheimer’s disease benefited more from following a Mediterranean-style diet, showing a greater reduction in related dementia risk compared to those at lower genetic risk.

Another clinical trial found that following a Mediterranean diet while eating fewer calories, doing moderate exercise, and adhering to professional support for weight loss can lower type 2 diabetes risk by 31%.