Cognitive decline reduced by MIND diet, especially for women and Black people, study finds

Leafy green vegetables, berries, whole grains, seeds, and a bit of fish and poultry are staples of the MIND diet. (jenifoto/iStockphoto/Getty Images via CNN Newsource)

Following the MIND diet for 10 years produced a small but significant decrease in the risk of developing thinking, concentration and memory problems, a new study found.

The Mediterranean-DASH Intervention for Neurodegenerative Delay diet combines elements from the traditional Mediterranean diet and the Dietary Approaches to Stop Hypertension, or DASH diet, which focuses on reducing blood pressure.

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The MIND diet was specifically designed to combat cognitive decline, said lead study author Dr. Russell Sawyer, an assistant professor of clinical neurology and rehabilitation medicine at the University of Cincinnati Gardner Neuroscience Institute.

“Among the MIND diet components are 10 brain-healthyfood groups — green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, seafood, poultry, olive oil and wine,” Sawyer said in an email.

Five unhealthy food groups — red meats, butter and stick margarine, cheese, fried and fast foods, and pastries and sweets — are limited in the MIND diet, which helps reduce the intake of trans and saturated fats, Sawyer said.

“The MIND diet has all the key features — notably an emphasis on real food, mostly plants — required to reduce systemic inflammation, facilitate weight loss, improve the health of the microbiome, ameliorate insulin resistance, lower elevated blood lipids (fats), and slow atherogenesis (clogging of arteries),” said Dr. David Katz, a specialist in preventive and lifestyle medicine who founded the nonprofit True Health Initiative, a global coalition of experts dedicated to evidence-based lifestyle medicine. He was not involved in the study.

“That such effects would translate into protection of the brain is anything but a surprise,” Katz said in an email. “This study of association does not, by itself, prove that the MIND diet protects cognitive health, but given the clear mechanisms in play, it certainly suggests it does.”

A larger benefit for women and Black people

The study, published Wednesday in Neurology, the journal of the American Academy of Neurology, is part of an ongoing study called REGARDS, or Reasons for Geographic and Racial Differences in Stroke. Sponsored by the National Institutes of Health, REGARDS was created to examine why Southern American and Black American people have a higher incidence of stroke, and it has been following about 30,000 adults age 45 and older since 2003.

Of the more than 14,000 people in the study, 70 per cent were White and 30 per cent were Black. At the start of the study, and again at 10 years, participants were asked about their dietary intake and underwent electrocardiograms, blood pressure measurements and blood work.

Researchers then scored the diets on higher adherence to MIND diet parameters: eating more than three servings of whole grains per day, consuming more than six servings of green leafy vegetables each week, eating at least one other vegetable each day, eating more than two servings of berries each week, having a fish meal more than once and poultry more than twice a week, and eating beans more than three times per week. Eating nuts and using primarily olive oil were also scored more highly.

People who ate red or processed meats less than four times a week, fried or fast food less than once a week, and less than a tablespoon of butter or margarine a day were also scored higher.

People who followed the MIND diet more closely were 4 per cent less likely to develop memory and thinking problems than those who did not adhere to the diet, the study found. The finding remained even after mitigating factors such as exercise, education, smoking, body mass index, medical conditions, age, and anxiety or depression were factored out.

For women, the risk was even less — they were 6 per cent less likely to develop cognitive impairment. Men, however, saw no such benefit, the study found.

When it came to how quickly those with such memory and thinking issues declined, the study found that people who closely followed the MIND Diet regressed more slowly than those who did not. That association was stronger in Black participants than in White participants, Sawyer said.

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“These were surprising findings,” Sawyer said. “The benefits of the MIND diet may have a differential impact in women and Blacks and this is an area for future research.”

More research needed

A 2023 randomized controlled clinical trial found the MIND diet no better than the control diet in reducing signs of cognitive decline in the brain. However, experts were concerned the trial was not long enough to fully capture results.

“The three years follow up, while admirable for a randomized clinical trial provides less insights about the long-term benefits of diet compared to the 10+ years of follow up in our study,” Sawyer said.

In addition, only 66 people in the clinical trial were Black, which limits “the generalizability of this randomized control study compared to our cohort study, though both offer important information,” he said.