What you eat at age 40 can affect your quality of life at age 70

We all want to age gracefully, but a new study has found that fewer than one in 10 people were able to live disease-free and maintain good physical, cognitive and mental health into age 70 and beyond. The research suggests that sticking to a healthy diet throughout middle age could increase your chances of healthy aging.

The study, which is based on data from more than 100,000 people over a 30-year period, found that people who followed a healthy diet from age 40 were 43-84% more likely to have good physical and mental functioning at age 70 than those who did not.

“People who followed healthy diets in midlife, particularly those rich in fruits, vegetables, whole grains, and healthy fats, were significantly more likely to age healthily,” said Anne-Julie Tessier, Ph.D., a postdoctoral researcher at the Harvard T.H. Chan School of Public Health. “This suggests that what you eat in midlife may play a big role in how well you age.”

Tessier presented the findings at FOOD 2024the main annual meeting of the American Society for Nutrition, held from June 29 to July 2 in Chicago.

In terms of specific foods, the researchers found that higher intakes of fruits, vegetables, whole grains, unsaturated fats, nuts, legumes, and low-fat dairy products were linked to a greater likelihood of healthy aging, while higher intakes of trans fat, sodium, meat, red and processed meat were linked to a lower likelihood of healthy aging.

While many previous studies have shown that a healthy diet can help prevent chronic diseases, the new research is unique in its focus on healthy aging, defined not only as the absence of disease, but also as the ability to live independently and enjoy a good quality of life as we age.

“Traditionally, research and derived dietary guidelines have focused on preventing chronic diseases such as heart disease,” Tessier said. “Our study provides evidence for dietary recommendations to consider not only disease prevention, but also to promote overall healthy aging as a long-term goal.”

Researchers analyzed data from more than 106,000 people dating back to 1986. Participants were at least 39 years old and free of chronic disease at the start of the study and provided information about their diet via questionnaires every four years. By 2016, nearly half of the study participants had died, and only 9.2 percent survived to age 70 or older, while remaining free of chronic disease and in good physical, cognitive, and mental health.

The researchers compared rates of healthy aging among people in the highest versus lowest quantiles of adherence to each of eight healthy eating patterns defined by previous scientific studies. The strongest correlation was seen with the alternative healthy eating index, a pattern that reflects close adherence to the Dietary Guidelines for Americans. Participants in the highest quantile for this eating pattern were 84 percent more likely to age healthily than those in the lowest quantile.

Strong correlations were also found for the Empirical Dietary Index for Hyperinsulinemia Diet (associated with a 78% greater chance of healthy aging), Planetary Health Diet (68%), Alternative Mediterranean Diet (67%), Dietary Approaches to Stop Hypertension (DASH) (66%), Mediterranean-DASH Intervention for Neurodegenerative Slowing (MIND) diet (59%), and Empirical Dietary Inflammatory Pattern (58%). A slightly more modest association was found for the healthy plant-based diet (43%).

“A striking finding was the association between a healthy diet and healthy aging,” Tessier said.

“This diet is based on the EAT Lancet Commission report, which emphasises fruits, vegetables, whole grains, plant proteins and healthy fats from sustainable sources. The fact that it emerged as one of the key dietary patterns associated with healthy ageing is particularly interesting as it supports that we can eat a diet that can benefit both our health and the planet.”

The links between diet and healthy aging remained strong, even when the researchers took into account physical activity and other factors known to affect health. Tessier noted that each of the healthy dietary patterns was associated with healthy aging as a whole, as well as with the individual components of healthy aging, including physical health, cognitive functioning and mental health.

Given the study’s focus on dietary patterns in midlife, Tessier said future research could help clarify the potential consequences of switching to a healthier diet later in life.