Unique diet slows brain aging by more than two years

The Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) diet are both considered healthy choices that reduce the odds of heart disease and several other ills.

But a new study published in the Journal of Neurology Neurosurgery & Psychiatry finds some magic in combining the two. The result, nicknamed the MIND diet, in a study of more than 1,600 people was credited with slowing brain structure changes associated with aging by two years.

The study’s background material reported that the diet “is associated with less tissue loss over time, especially gray matter — the brain’s information processing hub, with a key role in memory, learning, and decision-making — and less ventricular enlargement, which reflects brain atrophy, where tissue loss is accompanied by the enlargement of cerebrospinal fluid-filled spaces."

It’s not known, the researchers said, whether the diet has an impact on the age-related changes in the brain that are linked to neurodegenerative diseases like Alzheimer’s or Parkinson’s disease.

What is the MIND diet?

The aptly named MIND diet focuses on basing dietary decisions around consumption of vegetables, including especially leafy green vegetables, berries, nuts, whole grains, fish, poultry, beans and olive oil. A moderate amount of wine is allowed, but eating butter/margarine, cheese, red meat, pastries/sweets and fried fast foods is discouraged.

MIND is much-needed shorthand for the diet’s full name: The Mediterranean–Dietary Approaches to Stop Hypertension Diet Intervention for Neurodegenerative Delay. This isn’t the first study to herald MIND as possibly a boon to cognitive health.

Study nuts and bolts

The 1,647 middle-aged and older adults in the study were part of the long-term Framingham Heart Study Offspring cohort. At the start of the study, their average age was 60 and they each showed no signs on MRI of having had a stroke or dementia. Each had a health assessment every four to eight years, along with an MRI brain scan every two to six years, starting in 1999. They were followed for an average of just over 12 years.

They also had to fill out at least one food frequency survey showing what they ate at their checkups between 1991 and 1995, 1995 to 1998 and/or 1998 to 2001.

Adherence to the MIND diet was scored and on average they earned 7 out of a possible 15 points. Women and those with a college education, nonsmokers and people in the normal weight range were more likely to score in the top third for adherence than others. That group was also less likely than others to have brain-affecting health issues such as type 2 diabetes, high blood pressure or heart disease.

Per a news release, “During an average monitoring period of 12 years, reductions in total brain, gray matter, white matter and hippocampal volumes, alongside increased cerebrospinal fluid, ventricular volumes and white matter hyperintensities — bright spots indicative of tissue damage— were evident on the MRI scans of all the participants.“

No one escaped some effects of aging.

But more closely following the MIND diet was linked to slower gray matter shrinkage and loss equal to about 2.5 years of delayed brain aging. And each 3-point increase in the diet score was associated with about 8% less tissue loss and a year of delayed brain aging.

The researchers especially noted beneficial associations with eating berries and poultry.

At the same time, higher intake of sweets was associated with speedier ventricular expansion and atrophy in the hippocampus, which also was seen in those consuming fried fast food.

The researchers said that foods like berries that contain a lot of antioxidants and “high-quality” protein like chicken “may reduce oxidative stress and mitigate neuronal damage.” They noted that eating fried fast foods that have unhealthy fats might lead to inflammation and vascular damage.

Surprises and limitations

There were also a couple of surprises in the findings, they noted. “Unexpectedly, higher whole grain intake was associated with unfavorable structural changes, including faster declines in gray matter and hippocampal volume, and faster ventricular expansion, while higher cheese intake was associated with slower reductions in grey matter and hippocampal volume and less ventricular enlargement and fewer bright spots.”

The associations noted were clearer among older participants and also among those who were more physically active and had a healthy weight. That could suggest “combined lifestyle strategies” might lower risk of brain degeneration, the researchers said.

There are potential limitations, starting with the fact it’s an observational study, per the researchers. And food questionnaires can be subject to recall bias. Further, the study team reported it couldn’t “exclude mild cognitive impairment” when the brain scans were done. And dietary habits could have changed over time. Nor could they exclude genetic risks.

Dr. David Katz, a specialist in preventive and lifestyle medicine and who was not involved in the research, told CNN that the study could not prove cause and effect or reverse causality, “which occurs when the impact of an action is actually the cause.”

“In other words, people with healthier brain structure and function over time may have made better dietary choices,” he said in an email. “But the more obvious causal pathway — eating well is good for brain structure and function — is the more plausible.”

The researchers also noted that most of the participants were white, so it’s hard to say if findings would apply to other racial or ethnic groups. But they did conclude that the MIND diet has potential as a brain-healthy eating pattern that is among strategies designed to slow brain decline as people age.

The international study was led by researchers at Zhejiang University School of Medicine in Hangzhou, China. The Alzheimer’s Association, Zhejiang University Global Partnership Fund and Fundamental Research Funds for the Central Universities provided funding.