Carbohydrate Choices in Midlife Affect Aging Outcomes

What kind of carbohydrates you eat in midlife might shape how well you age, suggests a new study from Tufts University and Harvard T.H. Chan School of Public Health, which tracked over 47,000 women over 3 decades.

The findings, published in JAMA Network Open, linked higher intake of high-quality carbs and fiber to better physical and cognitive health in later life.

The link between carb quality and aging

As people live longer, the focus has shifted from simply extending lifespan to improving how we age. That means fewer chronic diseases and better mental, physical and cognitive function in later life.

Carbohydrates provide about half of daily energy intake, but vary widely in quality. Refined carbs, such as white bread and sugary foods, offer little nutritional value. In contrast, whole grains, fruits, legumes and vegetables contain more fiber and nutrients.

High-quality carbohydrates have been tied to lower risks of heart disease, type 2 diabetes and certain cancers. Still, less is known about how they influence long-term health – especially aging. Do the kinds of carbs people eat in midlife affect how well they function decades later?

Previous studies often focus on disease risk or short-term outcomes. What’s been missing is a long-term look at how carb quality might relate to the full picture of aging, including memory, mobility and mental health.

“We’ve all heard that different carbohydrates can affect health differently, whether for weight, energy or blood sugar levels,” said lead author Dr. Andres Ardisson Korat, a scientist at Tufts University. “But rather than just look at the immediate effects of these macronutrients, we wanted to understand what they might mean for good health 30 years later.”

What the 30-year study says about carbs and aging

The study looks at how the quality and type of carbohydrates eaten in midlife relate to healthy aging in women, using decades of data from the long-running Nurses’ Health Study.

 

 

The team tracked more than 47,000 women from 1984 to 2016. The women were under 60 years old at the start and aged 70–93 years by the final follow-up. Every four years, participants filled out detailed food-frequency questionnaires. Data on their physical health, mental wellbeing, memory and daily function was also collected.

To be classed as a “healthy ager,” a participant had to have no major chronic illnesses, no serious memory or physical impairments and good mental health by later life. The 11 chronic conditions included in the definition ranged from cancer and diabetes to heart disease and neurodegenerative disorders.

Only 8% met this high bar.

The analysis looked at different types of carbohydrates: total intake, high-quality sources (including whole grains, fruits, vegetables and legumes) and refined sources (such as added sugars, white bread and potatoes). They also measured dietary fiber and how carb intake affected blood sugar, using glycemic index and load.

 

 

Fiber from fruits, vegetables and cereals was each linked with higher odds of healthy aging.

Women who ate more high-quality carbohydrates and fiber in midlife had between 6%–37% higher odds of aging healthily. In contrast, higher intake of refined carbs and starchy vegetables was linked to a 13% drop in those odds.

The positive associations extended across physical function, memory and mental health – not just disease status.

A higher glycemic index and carbohydrate-to-fiber ratio were also linked with lower odds of healthy aging.

“Our findings suggest that carbohydrate quality may be an important factor in healthy aging,” said Korat.

The difference in quality – refined vs unrefined – appeared to matter decades later.

The researchers also estimated that replacing refined carbs, fat or animal protein with high-quality carbohydrates was associated with higher odds of healthy aging.

Future directions for diet and healthy aging

This study offers observational evidence that the types of carbohydrates people eat in midlife may be linked to how well they age. The data suggest that higher intakes of fiber and unrefined carbohydrates were associated with better health outcomes decades later.

“Our results are consistent with other evidence linking consumption of fruits and vegetables, whole grains and legumes with lower risks of chronic diseases, and now we see the association with physical and cognitive function outcomes,” said senior author Dr. Qi Sun, an associate professor in the Departments of Nutrition and Epidemiology at Harvard T.H. Chan School of Public Health.

However, the study has limitations. The cohort was made up mostly of white female health professionals, which means the findings may not apply to everyone. Dietary information was also based on self-reported data, which can be inaccurate.

Researchers say more work is needed to understand why fiber and unrefined carbohydrates might be linked to healthier aging. Future studies should include more diverse populations and focus on the biological mechanisms behind these links.

“Studies are starting to find an association between food choices in midlife and quality of life in later years,” said Korat. “The more we can understand about healthy aging, the more science can help people live healthier for longer.”

 

Reference: Korat AVA, Duscova E, Shea MK, et al. Dietary carbohydrate intake, carbohydrate quality, and healthy aging in women. JAMA Netw Open. 2025. doi: 10.1001/jamanetworkopen.2025.11056

This article is a rework of a press release issued by Tufts University. Material has been edited for length and content.