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ISLAMABAD (Web-Desk); A new study has raised important questions about the benefits of the Mediterranean diet on brain health, suggesting it may not offer the same cognitive protection for all aging populations, particularly older African Americans.

The Mediterranean diet, rich in fruits, vegetables, whole grains, fish, and olive oil, has long been celebrated for lowering risks of heart disease, diabetes, obesity, and certain cancers. Previous research has also linked it to reduced chances of cognitive decline, Alzheimer’s disease, and other forms of dementia.

However, new findings published in Preventive Medicine Reports indicate otherwise for African American communities. Researchers tracked 185 participants, with an average age of 66 and mostly identifying as non-Hispanic Black or African American. Participants were randomly assigned to follow an eight-month Mediterranean diet intervention—focused either on weight loss or without it—followed by a six-month maintenance period.

At the end of the study, scientists found that although participants achieved meaningful weight loss and reduced visceral fat, there was no measurable improvement in cognitive function. “We believe longer interventions are necessary, similar to the five-year PREDIMED trial in Spain, to detect cognitive benefits,” explained lead author Dr. Andrew McLeod from the University of Illinois Chicago.

Interestingly, participants who adhered to the diet with weight loss lost an average of 3.8 kg over 14 months. Researchers see this as significant, suggesting that prolonged adherence could eventually yield cognitive, cardiovascular, and metabolic advantages, potentially extending both lifespan and healthspan.

Dr. McLeod noted that future research may explore why some participants adhered better to the diet than others, and whether factors like social support played a role. They also plan to investigate if smaller subgroups did experience cognitive gains.

Geriatric psychiatrist Dr. Rehan Aziz from Jersey Shore University Medical Center welcomed the study for prioritizing cultural representation, a rarity in dementia prevention trials. “I wasn’t surprised by the lack of short-term cognitive improvement,” he said. “Brain health takes years to change. A longer study with greater BMI reductions might have shown different results. Still, improved diet quality and weight loss are wins that could indirectly reduce dementia risk through better heart and metabolic health.”

Dr. Aziz pointed out why cognitive improvements weren’t observed: “The trial only lasted 14 months, and meaningful cognitive change often requires years. Also, while participants did improve diet and lose weight, the differences may not have been large enough to impact the brain. Deeper metabolic changes, like insulin sensitivity, might be key and didn’t shift much in this group.”

Dr. David Cutler of Providence Saint John’s Health Center in California agreed. “The Mediterranean diet still shows promise for overall health, especially fat reduction,” he said. “While this study didn’t capture cognitive benefits, it doesn’t rule them out—longer follow-ups might reveal them. Measuring cognition is also inherently more complex than tracking weight or waist size.”

Experts stress this shouldn’t discourage adoption of Mediterranean eating. “It remains vastly superior to high-fat, low-vegetable diets,” Dr. Cutler added. “Even if we didn’t see brain changes yet, the diet’s metabolic and cardiovascular perks shouldn’t be overlooked.”

Ultimately, researchers and clinicians agree: more long-term studies, especially centered on African American communities, are critical to uncover how diet impacts brain aging and to tailor effective prevention strategies.