New research has linked a healthier diet to a reduced risk of dementia and a deceleration in the pace of aging. This study, published in the Annals of Neurology, provides new insights into how diet can influence the complex mechanisms of aging and cognitive health.
Dementia is a term used to describe a group of symptoms affecting memory, thinking, and social abilities severely enough to interfere with daily functioning. It’s not a single disease but rather a general term that covers a wide range of specific medical conditions, including Alzheimer’s disease, which is the most common form of dementia among older adults.
Dementia is characterized by a decline in cognitive functions such as memory loss, language skills, problem-solving abilities, and the ability to perform everyday activities. It results from damage to or loss of nerve cells and their connections in the brain, varying in cause and progression depending on the type of dementia.
The motivation behind this study stemmed from the growing body of evidence suggesting that what we eat plays a crucial role in how our bodies age and our risk for age-related diseases like dementia. Prior research has hinted at the protective effects of a healthy diet on cognitive function and the slowing down of biological aging processes.
However, the biological underpinnings of these effects were not fully understood. By investigating the relationship between diet, the pace of biological aging, and the incidence of dementia, the researchers aimed to shed light on the possible mechanisms through which diet influences our long-term health and cognitive resilience.
“Much attention to nutrition in dementia research focuses on the way specific nutrients affect the brain,” said Daniel Belsky, an associate professor of Epidemiology at Columbia School of Public Health and the Columbia Aging Center, and 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 analyzed data from the second generation of participants in the Framingham Heart Study Offspring Cohort. This cohort, initiated in 1971, includes data from physical examinations, lifestyle questionnaires, blood samples, and neurocognitive tests collected approximately every 4-7 years.
As a measure of a healthy diet, the researchers assessed the participants’ long-term adherence to the Mediterranean-Dash Intervention for Neurodegenerative Delay (MIND) diet. The diet combines elements of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets, focusing on foods that are believed to support brain health. It emphasizes consumption of vegetables, berries, nuts, whole grains, olive oil, and fish, aiming to reduce the risk of neurodegenerative diseases.
The researchers measured the pace of biological aging through the DunedinPACE epigenetic clock, a tool that estimates aging based on DNA methylation patterns. The study focused on participants who were 60 years or older and free of dementia at the start of the analysis, encompassing 1,644 individuals.
Participants with higher adherence to the MIND diet exhibited a slower pace of biological aging, as indicated by lower DunedinPACE scores. Additionally, a healthier diet was associated with a significantly lower risk of developing dementia.
Importantly, the study found that part of the reason a healthier diet can lower the risk of dementia is because it slows down the pace of biological aging. Specifically, 27% of the diet’s protective effect against dementia was mediated through its impact on slowing biological aging. In simpler terms, a healthier diet might help reduce the risk of dementia partly by keeping the body and brain “younger” for longer.
The research also explored the relationship between diet, pace of biological aging, and the risk of death from any cause. It found that a slower pace of biological aging, influenced by diet, accounted for 57% of the diet’s beneficial effect on lowering mortality risk. This indicates that the benefits of a healthy diet extend beyond cognitive health to overall longevity.
“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, a postdoctoral researcher at the Columbia Department of Neurology and Taub Institute for Research on Alzheimer’s Disease and the Aging Brain. “However, a portion of the diet-dementia association remains unexplained, therefore we believe that continued investigation of brain-specific mechanisms in well-designed mediation studies is warranted.”
“We suggest that additional observational studies be conducted to investigate direct associations of nutrients with brain aging, and if our observations are also confirmed in more diverse populations, monitoring biological aging, may indeed, inform dementia prevention,” noted Belsky.
The study, “Diet, Pace of Biological Aging, and Risk of Dementia in the Framingham Heart Study,” was authored by Aline Thomas, Calen P. Ryan, Avshalom Caspi, Zhonghua Liu, Terrie E. Moffitt , Karen Sugden, Jiayi Zhou MPH, Daniel W. Belsky PhD, Yian Gu MD, PhD