Healthy eating increases odds of reaching 70 without chronic disease, study says

Following a healthy diet — one primarily plant-based, with minimal ultra-processed food and low to moderate amounts of animal-based foods like fish and dairy — can raise the chances of reaching age 70 without developing a chronic disease, according to a new study.

The research, published Monday in the journal Nature Medicine, analyzed the diets of more than 105,000 people in midlife and found that by 70, less than 10% had achieved “healthy aging,” meaning their memories were intact, they hadn’t developed depression or a major chronic condition, and they could perform basic physical tasks like climbing stairs or carrying groceries.

Eating healthy, the analysis showed, increased participants’ likelihood of reaching that milestone. That held true for eight specific diets evaluated, including the Mediterranean diet and strictly plant-based regimens, as well as diets designed to lower inflammation or blood pressure. 

“What most of these diets had in common was that they were rich in fruit and vegetables, whole grains, unsaturated fat, nuts, legumes and then low in processed meat, sugars and trans fat,” said an author of the study, Marta Guasch-Ferré, an adjunct associate professor of nutrition at the Harvard T.H. Chan School of Public Health.

Previous studies have similarly found that diets rich in fruits and vegetables are associated with lower cholesterol and blood pressure and a decreased risk of heart disease or cancer. But most of that research hasn’t evaluated the overall effect on people’s quality of life as they age, Guasch-Ferré said.

“It’s not just about living longer but also maintaining good health in the later stages of life,” she said.

The link between a healthy diet and lower disease risk is a major talking point for Health and Human Services Secretary Robert F. Kennedy Jr., who has repeatedly blamed food additives and processed food consumption for rising rates of chronic disease in the United States.

The new study evaluated participants ages 39 to 69 over 30 years from 1986 to 2016. The group was selected from two databases of health professionals, so it may skew more health-conscious than average. In addition to evaluating people’s mental and physical fitness at age 70, the researchers screened for 11 chronic conditions, including cancer, diabetes, stroke, multiple sclerosis and Parkinson’s disease. 

In particular, the Alternative Healthy Eating Index — a diet designed to reduce chronic disease — had the strongest association with healthy aging. The index awards high scores to people who consume small amounts of fish, at least five daily servings of vegetables and at least four daily servings of whole fruits while cutting out red meat, sugar-sweetened beverages and fruit juice. 

Participants who scored the highest on the Alternative Healthy Eating Index had an 86% greater likelihood of healthy aging, the study found, compared with participants with the lowest scores. 

The U.S. dietary guidelines don’t adhere completely to the index, recommending instead at least three vegetable servings and at least two fruit servings per day, plus protein from lean meat, poultry, fish, eggs, beans or nuts. 

All eight diets in the study promoted fruits, vegetables and whole grains over red and processed meats. But there are slight differences: For instance, the Mediterranean diet emphasizes healthy fats such as olive oil, fish and nuts, while the Dietary Approaches to Stop Hypertension diet prioritizes low-sodium foods. The MIND diet, a combination of those two, encourages people to eat berries to promote brain health.

While past research has found numerous health benefits associated with vegetarian or vegan diets, Guasch-Ferré said the study’s findings suggest that middle-aged people don’t need to be fully vegetarian to stave off disease.

“We can reduce our intake of animal food, but still, some amounts may be healthy,” she said.

The study doesn’t address whether a healthy diet in midlife can reverse the negative effects of a poor diet in childhood or young adulthood — a question researchers hope to answer.

“With respect to many lifestyle factors, our mantra typically is it’s never too early and it’s never too late,” said Stephen Kritchevsky, a professor of gerontology at Wake Forest University School of Medicine, who wasn’t involved in the study.

Diet isn’t the only factor that affects aging, he added — physical activity, stress and a person’s genetics can also play roles.

“If people want to age healthily, the top four things in my mind are: maintain a healthy weight, get exercise, eat well … and don’t smoke,” Kritchevsky said.