Harvard study reveals the best diets for healthy aging and Alternative Healthy Eating Index emerges the winner

Aging is an inevitable part of life. As they age, most people often encounter chronic diseases, which drastically slashes the quality of their lives. People over the age of 70 often struggle with cognitive, physical, and mental health. But what if you can step into your 70s free of any health struggles? Yes, it's possible. A new study by researchers at Harvard TH Chan School of Public Health, the University of Copenhagen, and the University of Montreal has cracked the code to healthy aging. And, the key is closer than you think - right on your plate!

In the study published in Nature Medicine, the researchers found that individuals who followed healthy dietary patterns in midlife had a better chance of reaching age 70 without major chronic diseases and maintaining cognitive, physical, and mental health. The study is among the first to examine multiple dietary patterns in midlife in relation to overall healthy aging.

“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, Fredrick J. Stare Professor of Nutrition and Epidemiology and chair of the Department of Nutrition at Harvard Chan School said in a statement.

Researchers analyzed data from over 105,000 men and women aged between 39 and 69 for 30 years using information from the Nurses’ Health Study and the Health Professionals Follow-Up Study. The participants were asked to answer dietary questionnaires, and their responses were scored based on adherence to eight 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).

Each of these diets focused on a high intake of fruits, vegetables, whole grains, unsaturated fats, nuts, and legumes. Some also include low to moderate intake of healthy animal-based foods such as fish and certain dairy products. Researchers also looked at participants’ intake of ultra-processed foods. They found that 9,771 participants (which is 9.3% of the study population) aged healthfully. They also learned that following any one of the healthy dietary patterns was linked to overall healthy aging.

The healthiest among the diets was the AHEI, developed to prevent chronic diseases. Participants, who followed AHEI, had an 86% greater likelihood of healthy aging at 70 years and a 2.2-fold higher likelihood of healthy aging at 75 years, compared to others. The AHEI diet is rich in fruits, vegetables, whole grains, nuts, legumes, and healthy fats and low in red and processed meats, sugar-sweetened beverages, sodium, and refined grains.

The top 2 was the PHDI diet which was high on plant-based foods and low on animal-based foods.

On the other hand, ultra-processed foods, especially processed meat and sugary and diet beverages, were associated with lower chances of healthy aging.

“Since staying active and independent is a priority for both individuals and public health, research on healthy aging is essential,” co-corresponding author Marta Guasch-Ferré, associate professor at the University of Copenhagen and adjunct associate professor of nutrition at Harvard Chan School said. “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.”

The study also emphasized that there is ‘no one-size-fits-all diet’ and that healthy diets can be adapted to fit individual needs and preferences.