What you eat at age 40 could influence your quality of life at 70

We all want to age with grace, but a new study has found that fewer than one in 10 people were able to live free of disease and maintain good physical, cognitive and mental health to age 70 and beyond. The study suggests that sticking to a healthy diet in midlife could increase your chance of achieving healthy aging.

The research, based on data from over 100,000 people spanning 30 years, revealed that people who followed a healthy diet from their 40s onward were 43-84% more likely to be well-functioning physically and mentally at age 70 compared with those who did not.

"People who adhered to healthy dietary patterns in midlife, especially those rich in fruits, vegetables, whole grains and healthy fats, were significantly more likely to achieve healthy aging," said Anne-Julie Tessier, Ph.D., postdoctoral fellow at Harvard TH Chan School of Public Health. "This suggests that what you eat in midlife can play a big role in how well you age."

Tessier presented the findings at NUTRITION 2024, the flagship annual meeting of the American Society for Nutrition held June 29–July 2 in Chicago.

In terms of particular foods, the researchers found that higher intakes of fruits, vegetables, whole grains, unsaturated fats, nuts, legumes and low-fat dairy were associated with greater odds of healthy aging, while higher intakes of trans fat, sodium, total meats, red and processed meats were associated with a lower odds of healthy aging.

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

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

Researchers analyzed data from over 106,000 people going back to 1986. Participants were at least 39 years old and free of chronic diseases at the start of the study and provided information about their diet via questionnaires every four years. As of 2016, nearly half of the study participants had died and only 9.2% survived to age 70 or older while maintaining freedom from chronic diseases and good physical, cognitive and mental health.

The researchers compared rates of healthy aging among people in the highest versus lowest quintiles for adherence to each of eight healthy dietary patterns that have been 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 top quintile for this dietary pattern were 84% more likely to achieve healthy aging than those in the bottom quintile.

Strong correlations were also found for the empirical dietary index for hyperinsulinemia diet (associated with a 78% greater likelihood of healthy aging), planetary health diet (68%), alternative Mediterranean diet (67%), dietary approaches to stop hypertension (DASH) diet (66%), the Mediterranean-DASH intervention for neurodegenerative delay (MIND) diet (59%) and empirical dietary inflammatory pattern (58%). A somewhat more modest association was found for the healthful plant-based diet (43%).

"A finding that stood out was the association between the planetary health diet and healthy aging," said Tessier.

"This diet is based on the EAT Lancet Commission's report which emphasizes fruits, vegetables, whole grains, plant proteins and healthy fats from sustainable sources. The fact that it emerged as one of the leading dietary patterns associated with healthy aging is particularly interesting because it supports that we can eat a diet that may benefit both our health and the planet."

The ties between diet and healthy aging remained strong even when the researchers accounted for physical activity and other factors that are known to impact health. Tessier noted that each of the healthy dietary patterns was linked 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 middle age, Tessier said that future research could help to elucidate the potential impacts of switching to a healthier dietary pattern later in life.