What if your doctor told you that you could make your brain younger simply by eating more greens each week and avoiding high fat, high calorie foods? Would you?

Two healthy diets, the Mediterranean diet and the Mediterranean-DASH Intervention for Neurodegenerative Delay or MIND diet, appear to do that. Both have long been known to be associated with better heart and brain health. A recent study offers an even more concrete picture of how they benefit the brain.

Eating more fruits and vegetables and fewer foods high in fat and sugar appears to reduce the development of the beta-amyloid plaques and tau tangles connected to cognitive decline and Alzheimer’s disease.

Each one-point increase in the MIND diet score meant the number of plaques in the brain was equal to that of participants more than four years younger.

Researchers from Rush Medical College found that seniors who had most closely adhered to the Mediterranean diet or the MIND diet had fewer of the beta-amyloid plaques and tau tangles characteristic of Alzheimer’s disease in their brains at autopsy than those who did not closely follow those diets.

In particular, those who ate seven or more servings of leafy green vegetables per week had levels of plaques and tangles in their brains similar to those seen in people 18 years younger, compared to seniors who ate the just one or fewer servings per week.

“Our finding that eating more leafy green vegetables is associated with fewer signs of Alzheimer’s disease in the brain is intriguing enough for people to consider adding more of these vegetables to their diet,” lead author on the study, Puja Agarwal, an assistant professor at Rush Medical College, told TheDoctor.

More than 580 participants in the Rush Memory and Aging Project with an average age of 84 were enrolled in the study. Information about participants’ diets was collected annually over an average seven-year follow-up period. Participants filled out questionnaires asking how much food they consumed in certain categories.

Thirty-nine percent of participants had been diagnosed with dementia right before they died. Upon autopsy, the tau and beta-amyloid protein levels of 66 percent of them met the pathologic criteria for Alzheimer’s disease.

To get a picture of the effect diet had had on participants’ brains, researchers looked at the food questionnaires the seniors had filled out and ranked the quality of participants’ diets. Foods on the Mediterranean diet were divided into 11 categories, and participants were given a score of zero to 55.

Scores went up if a senior consumed whole grain cereals, fruits, vegetables, legumes, olive oil, fish and potatoes. Scores went down if they ate red meat, full fat dairy products and poultry.

Foods on the MIND diet were divided into 15 categories. Participants were given a score of zero to 15, and given one point for each food they consumed from 10 brain-healthy food groups that included nuts, berries, beans, whole grains, fish, poultry, olive oil and wine. They lost a point if they ate foods in five less healthy food groups like red meat, butter and margarine, cheese, pastries and sweets, and fried and fast food more often than recommended.

“Our finding that eating more leafy green vegetables is associated with fewer signs of Alzheimer’s disease in the brain is intriguing enough for people to consider adding more of these vegetables to their diet.”

Participants were divided into three groups for each diet based on their score. Those in the highest scoring group on the Mediterranean diet had an average score of 35, while those in the lowest scoring group had an average score of 26. Participants in the highest scoring group on the MIND diet had an average score of nine and those in the lowest scoring group had an average score of six.

Compared to those with less healthy diets and the lowest scores, people adhering most closely to the Mediterranean diet and having the highest scores had about the same number of beta amyloid plaques and tau tangles as people 18 years younger — even after taking into account their age at death, sex, education, total calorie intake and whether they had genes predisposing them to Alzheimer’s disease.

Similarly, participants with the highest scores for adhering to the MIND diet had amounts of plaques and tangles usually found in people 12 years younger. Each one-point increase in the MIND diet score meant the number of plaques in the brain was equal to that of participants more than four years younger. The study enrolled seniors who were mostly white, non-Hispanic older adults. Future studies will investigate more diverse populations and other pathways and mechanisms through which diet could help protect the brain, including vascular health and the role of inflammation.

The study is published in Neurology.