NEW YORK, July 2 (UPI) — What people eat at age 40 could affect the quality of their lives at age 70, a new Harvard study finds.
The results were presented Tuesday at the annual meeting of the American Society for Nutrition in Chicago.
In the study, researchers found that people who followed a healthy diet starting at age 40 were 43 to 84 percent more likely to function well physically and mentally at age 70 compared to those who did not.
The study, based on data from more than 100,000 people participating in the Nurses’ Health Study and the Harvard Health Professionals Follow-up Study, spanned 30 years.
“Diet is a major factor in preventing chronic disease, but few studies have examined and compared healthy diets and overall healthy aging encompassing cognition, physical and mental health,” study lead author Anne-Julie Tessier told UPI via email.
Higher intakes of fruits, vegetables, whole grains, unsaturated fats, nuts, legumes, and low-fat dairy products were associated with greater odds of healthy aging. In contrast, higher intakes of trans fats, sodium, and total meats, including processed meats, were associated with lower odds of healthy aging.
The study authors said their research was unique because it focused on healthy aging, which they defined not only as the absence of disease but also the ability to live independently and enjoy a good quality of life as people age.
“Traditionally, dietary recommendations have focused on preventing chronic diseases like heart disease,” says Tessier, a research associate in the department of nutrition at the TH Chan School of Public Health in Boston. She is a registered dietitian with a doctorate in nutrition.
She noted that the study results “will serve to inform public health recommendations by highlighting the importance of diet in midlife to promote overall healthy aging.”
The researchers analyzed data from more than 106,000 people since 1986. Participants were at least 39 years old and free of chronic diseases at the start of the study. Every four years, they answered questionnaires about their diet.
By 2016, nearly half of the study participants had died, and only 9.2% had survived to age 70 or older while avoiding chronic disease and maintaining good physical, cognitive, and mental health.
The researchers compared rates of healthy aging among people in the highest and lowest quintiles based on adherence to each of eight healthy dietary patterns defined by previous studies.
They observed the strongest correlation with the Alternative Healthy Eating Index, a pattern reflecting close adherence to the Dietary Guidelines for Americans. Participants in the top quintile for this dietary pattern were 84% more likely to age healthily than those in the bottom quintile.
Different dietary patterns are also strongly correlated with healthy aging: the hyperinsulinemic diet (associated with a 78% higher likelihood of healthy aging), the planetary health diet (68%), the alternative Mediterranean diet (67%), the Dietary Approaches to Stop Hypertension (DASH) diet (66%), the DASH-Mediterranean intervention diet for neurodegenerative delay (MIND) (59%), and the empirical dietary inflammatory model (58%).
The association was somewhat more modest for the healthy plant-based diet (43%).
“A novel finding was the association between a healthy diet and healthy aging,” Tessier said. “This diet is based on the EAT Lancet Commission report, which emphasizes fruits, vegetables, whole grains, plant proteins and healthy fats from sustainable sources.
“The fact that it has become one of the leading dietary patterns associated with healthy aging is particularly exciting because it shows that we can adopt a diet that can benefit both our health and the planet.”
The links between diet and healthy aging remained strong even after adjusting for other lifestyle factors known to influence health and socioeconomic status, Tessler noted.
She added that each healthy diet was linked to healthy aging in general, as well as to individual components of healthy aging, including physical health, cognitive functioning and mental health.
Given the study’s focus on the eating habits of middle-aged people, she said future research could shed light on the potential impacts of shifting to a healthier diet later in life.
“These findings reinforce many well-established dietary approaches that have been associated with better health,” said Kelly Kane, a registered dietitian and director of nutrition at Tufts Medical Center in Boston. She was not involved in the study.
“For example, the DASH (Dietary Approaches to Stop Hypertension) diet has been associated with lower blood pressure,” she said.
Confirming the importance of a diet rich in fruits, vegetables and whole grains is consistent with other recommendations for healthy aging, as well as minimizing risk and treating chronic diseases, such as high blood pressure, cardiovascular disease and diabetes, Kane said.
“This study gives us a clearer picture of which models may have the greatest impact on health,” she said. “However, the hardest part is applying these models to actual diets and food choices to reflect real-world eating.”
Kane recommended consulting a registered dietitian to adjust eating habits that would more closely align with these healthy habits.
More such studies would provide “an alternative rationale for why healthy eating throughout life is so important,” said Jacquelyn Davis, a registered dietitian and clinical nutrition manager at Bridgeport Hospital in Bridgeport, Connecticut.
While previous research has focused primarily on chronic disease prevention, this new study emphasizes the contribution of healthy eating to healthy aging and independent living as we age, Davis said.
“This may be a motivation for individuals to change their eating habits outside of the disease risk,” she said.
However, Dr. Jane Orient, executive director of the Association of American Physicians and Surgeons, said she would take the study “with a grain of salt” because of many confounding variables, including salt, calories, vitamins, socioeconomic status, education level and occupation.
“There’s been a big shift over the last 30 years in what’s considered a healthy diet — margarine versus butter, for example, or low-fat foods versus low-carb foods,” said Orient, a general internal medicine practitioner in Tucson, Arizona.
The jury is still out on which diet is best, she said, adding: “Are baby boomers who grew up cooking at home better off than those who eat mostly ‘convenience’ foods and tons of today’s snacks? The study, unfortunately, can’t answer that question.”