A new study from Harvard T.H. Chan School of Public Health shows that a plant-based diet, with moderate amounts of healthy animal-based foods and low intake of ultra-processed foods, can improve the chances of aging healthily. Healthy aging, in this study, is defined as living to age 70 without major chronic diseases and maintaining good mental, physical, and cognitive health.
The study, published in Nature Medicine on March 24, 2025, looked at the diets of over 105,000 men and women aged 39-69 over 30 years. Researchers analyzed data from the Nurses’ Health Study and the Health Professionals Follow-Up Study. Participants filled out regular dietary questionnaires, which the researchers used to score adherence to eight different healthy eating patterns. These included popular diets like the Mediterranean diet, DASH, and the MIND diet, all of which emphasize fruits, vegetables, whole grains, nuts, and healthy fats.
The study found that 9.3% of participants aged healthily. Following any of the healthy eating patterns was linked to better aging outcomes. The most beneficial diet was the Alternative Healthy Eating Index (AHEI), which focuses on preventing chronic diseases. People who followed the AHEI diet closely had an 86% higher chance of aging healthily by 70 and were 2.2 times more likely to age healthily by 75 compared to those who followed the diet less strictly.
A diet that considered both human and environmental health, like the Planetary Health Diet Index (PHDI), was also associated with better aging. On the other hand, diets high in ultra-processed foods, like sugary drinks and processed meats, lowered the chances of healthy aging.
Co-author Marta Guasch-Ferré, an associate professor at the University of Copenhagen, explained that research on healthy aging is crucial, especially as many people prioritize staying independent and active as they age. She added that plant-based diets, with some healthy animal-based foods, could be key in promoting overall healthy aging and shaping future dietary guidelines.
Lead author Anne-Julie Tessier from the University of Montreal emphasized that there is no one-size-fits-all diet. Healthy eating patterns can be personalized to suit individual needs and preferences.
While the study focused on health professionals, the researchers noted that repeating the study with a more diverse population would provide deeper insights.
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