Harvard T.H. Chan School of Public Health, alongside international partners, has identified dietary patterns in midlife linked to healthier aging. The study highlights the benefits of plant-based diets and low intake of ultra-processed foods in maintaining cognitive, physical and mental health into one’s 70s.
An extensive 30-year study involving over 105,000 middle-aged adults has linked maintaining a healthy, plant-based diet with an increased likelihood of healthy aging, defined as reaching age 70 free of major chronic diseases and with cognitive, physical and mental health maintained.
Conducted by researchers from the Harvard T.H. Chan School of Public Health, the University of Copenhagen and the University of Montreal, the study is set to be published today in Nature Medicine.
“Studies have previously investigated dietary patterns in the context of specific diseases or how long people live. Ours takes a multifaceted view, asking, how does diet impact people’s ability to live independently and enjoy a good quality of life as they age?” co-corresponding author Frank Hu, the Fredrick J. Stare Professor of Nutrition and Epidemiology and chair of the Department of Nutrition at Harvard Chan School, said in a news release.
The researchers utilized data from the Nurses’ Health Study and the Health Professionals Follow-Up Study to analyze the midlife diets and eventual health outcomes of participants, who ranged from ages 39 to 69.
Dietary habits were assessed using questionnaires, scored based on adherence to eight recognized healthy dietary patterns: the Alternative Healthy Eating Index (AHEI), the Alternative Mediterranean Index (aMED), the Dietary Approaches to Stop Hypertension (DASH), the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND), the healthful plant-based diet (hPDI), the Planetary Health Diet Index (PHDI), the empirically inflammatory dietary pattern (EDIP) and the empirical dietary index for hyperinsulinemia (EDIH).
These dietary patterns emphasize high intake of fruits, vegetables, whole grains, unsaturated fats, nuts and legumes, while some also include moderate intake of healthy animal-based foods like fish and certain dairy products.
The study found that adhering to any of these healthy diets was associated with overall healthy aging, affecting cognitive, physical and mental health positively.
Notably, the AHEI — a diet developed to prevent chronic diseases — proved particularly effective. Participants in the highest adherence quintile had an 86% higher likelihood of reaching age 70 healthily and a 2.2-fold greater chance by age 75, compared to those in the lowest adherence quintile.
The AHEI emphasizes fruits, vegetables, whole grains, nuts, legumes and healthy fats, alongside low intake of red and processed meats, sugary drinks, sodium and refined grains.
Another effective diet, the PHDI, focuses on both human and environmental health by promoting plant-based foods and limiting animal-based products.
Higher consumption of ultra-processed foods, including processed meats and sugary drinks, correlated with reduced chances of healthy aging.
“Since staying active and independent is a priority for both individuals and public health, research on healthy aging is essential,” added co-corresponding author Marta Guasch-Ferré, an associate professor in the Department of Public Health at the University of Copenhagen and adjunct associate professor of nutrition at Harvard Chan School. “Our findings suggest that dietary patterns rich in plant-based foods, with moderate inclusion of healthy animal-based foods, may promote overall healthy aging and help shape future dietary guidelines.”
“Our findings also show that there is no one-size-fits-all diet. Healthy diets can be adapted to fit individual needs and preferences,” added lead author Anne-Julie Tessier, an assistant professor in the Department of Nutrition at the University of Montreal, researcher at the Montreal Heart Institute and visiting scientist at Harvard Chan School.
Though the study primarily involved health professionals, it sets a significant precedent for future research across more diverse populations. The discoveries underscore the broad benefits of balanced, plant-rich diets in fostering not just longevity but a vibrant, healthy life in one’s later years.