Does the Mind diet prevent dementia?

If you’re concerned about developing dementia later in life, it’s natural to wonder if you might be able to prevent it.

Experts have estimated that 40 per cent of dementia cases worldwide might be prevented or delayed with certain modifiable factors, such as by prioritizing exercise and sleep and addressing health conditions like hearing loss or high blood pressure.

But a growing body of evidence suggests that diet may play a role in dementia prevention, too, said Puja Agarwal, a nutritional health researcher at the Rush University Medical Centre in Chicago.

Agarwal’s work has focused on evaluating how the Mediterranean-DASH Intervention for Neurodegenerative Delay, or Mind diet, which highlights certain foods thought to protect the brain, might influence dementia risk.

What is the Mind diet?

The Mind diet was first described in a 2015 study led by Martha Clare Morris, a nutritional health researcher at Rush University, who died in 2020.

Morris and her colleagues noted that in research studies, people who followed the Dash and Mediterranean diets — which prioritise fruits, vegetables, whole grains, lean proteins and healthy fats — tended to have better cognition than those who did not. They also observed that specific foods such as leafy greens, berries, nuts and whole grains were associated with better brain health.

Using these findings, Morris and her team devised the Mind diet. Like the Dash and Mediterranean diets, it emphasises whole grains, vegetables, nuts, beans, healthy fats and lean protein sources like poultry and fish; and it suggests limiting red and processed meats, cheese, sweets, fried foods and butter or margarine. The Mind diet is unique, however, in that it calls for at least six servings of leafy greens and two servings of berries each week.

Does the Mind diet benefit the brain?

In various studies that have tracked older adults’ eating patterns across many years, researchers have found that those who adhere most closely to the Mind diet tend to have slower rates of cognitive decline, reduced risks of dementia and fewer signs of Alzheimer’s disease in their brains after death than those who don’t.

Such results have been “promising,” said Debora Melo van Lent, an assistant professor of population health sciences at the University of Texas Health Science Center at San Antonio. But these studies can’t prove that the Mind diet itself leads to better brain health. For that, she said, you’d need a clinical trial.

The first Mind diet clinical trial was published in The New England Journal of Medicine in August. In the three-year study, researchers instructed half of the 604 participants — aged 65 and up — to follow the Mind diet and the other half to follow their typical diets. The participants were also counselled on reducing calories for weight loss.

However, the results were disappointing, said Dr Hussein Yassine, an associate professor of neurology at the Keck School of Medicine at the University of Southern California. The two groups had similar improvements on cognitive tests, and brain scans did not find major differences associated with cognitive decline.

Agarwal, who was one of the study’s authors, said this may have been a result of the study’s design and factors outside of the researchers’ control. The group that followed their typical diet, for instance, ended up consuming many components of the MIND diet, and each group lost weight, which may have contributed to similar improvements in cognitive function.