"Much attention to nutrition in dementia research focuses on the way specific nutrients affect the brain" said Daniel Belsky, PhD, a senior author of the study. “We tested the hypothesis that healthy diet protects against dementia by slowing down the body's overall pace of biological aging."
The researchers used data from the second generation of the Framingham Heart Study, the Offspring Cohort. Originating in 1971, participants in the latter were 60 years of age or older, were free of dementia, and also had available dietary, epigenetic, and follow-up data. The Offspring Cohort were followed-up at nine examinations, approximately every 4 to 7 years.
At each follow-up visit, data collection included a physical examination, lifestyle-related questionnaires, blood sampling, and, starting in 1991, neurocognitive testing.
Of 1,644 participants included in the analyses, 140 of the participants developed dementia.
To measure the pace of aging, the researchers used an epigenetic clock called DunedinPACE which measures how fast a person's body is deteriorating as they grow older, "like a speedometer for the biological processes of aging," explained Belsky.
"We have some strong evidence that a healthy diet can protect against dementia," said Yian Gu, PhD, the other senior author of the study. "But the mechanism of this protection is not well understood." Past research linked both diet and dementia risk to an accelerated pace of biological aging.
Belsky noted that "Testing the hypothesis that multi-system biological aging is a mechanism of underlying diet-dementia associations was the logical next step.
The research determined that higher adherence to the Mediterranean-Dash Intervention for Neurodegenerative Delay diet (MIND) slowed the pace of aging as measured by DunedinPACE and reduced risks for dementia and mortality. Furthermore, slower DunedinPACE accounted for 27% of the diet-dementia association and 57% of the diet-mortality association.
"Our findings suggest that slower pace of aging mediates part of the relationship of healthy diet with reduced dementia risk, and therefore, monitoring pace of aging may inform dementia prevention," said first author Aline Thomas, PhD.
