Healthy Diets Linked to Holistic Healthy Aging in Long-Term Harvard Study

Researchers at the Harvard T.H. Chan School of Public Health found that certain dietary patterns — such as avoiding processed foods and eating a balance of animal and plant-based foods — promote healthy aging after 30 years, according to a long-term study published Monday in the journal Nature Medicine.

“Maintaining a healthy diet that was rich in fruits, vegetables, whole grains, unsaturated fats, nuts, and legumes during mid-life was linked to a higher likelihood of healthy aging,” said Marta Guasch-Ferre, an adjunct associate professor of nutrition at the School of Public Health and a co-author of the study.

The study followed 70,091 women and 34,924 men over a period of 14 years, evaluating their adherence to eight self-reported diets and subsequent association to healthy aging. The participants started in middle age, and were deemed “healthy” at the end of the study if they lived to 70 years of age without chronic disease while surpassing cognitive, physical, and mental health benchmarks.

A collaboration between researchers at the School of Public Health and the University of Copenhagen and University of Montreal, the study used data from two pre existing studies — the Nurses’ Health Study and the Health Professionals Follow-Up Study — conducted from 1986 to 2016.

According to the study, a higher unsaturated fat intake was particularly correlated with longevity and maintained physical and cognitive abilities. Those who aged less healthily reported higher consumption of trans fats, sodium, and red and processed meats.

“All of the healthy diets that we studied were linked not only to overall healthy aging, but also to its individual domains, including cognitive, physical, and mental health,” said Anne-Julie Tessier, a lead researcher on the study and a visiting nutrition scientist at the Public Health School.

While many studies on the impacts of diet and lifestyle on aging take a disease-centered approach, this study is one of the first studies to evaluate the effect of dietary patterns on a “multidimensional” model of healthy aging.

“Healthy eating is not just diet, right? So there’s many other factors that affect these associations, such as physical activity, socioeconomic state, or even genetics,” Guasch-Ferre said. “There’s lots of layers that affect healthy aging.”

Of the eight dietary patterns that emerged, the Alternative Healthy Eating Index — which includes vegetables, fruits, whole grains, nuts, legumes, and healthy fats — was most strongly associated with healthy aging in both sexes.

The researchers analyzed the study’s results within subgroups stratified according to ancestry, sex, socioeconomic status, and lifestyle factors.

Participants with a higher socioeconomic status who took multivitamins, had higher levels of physical activity, and had a lower body mass index fell in the highest dietary score quintile and showed lower overall depression levels.

Tessier said that while striving for a nutrient-rich diet is essential, she added that there is no “one-size fits all” approach and not all foods need to be farm-fresh.

“It doesn’t have to be fresh fruits and vegetables. We can certainly choose frozen or canned, which are usually found at lower cost and with actually longer shelf life,” she said.

“It’s never too late to make any changes in your diet,” Tessier said.