A survey investigating the diet of thousands of women has shed new light on the link between protein consumption and healthy aging.
The study, which was based on self-reported data from more than 48,000 female healthcare professionals, found that those who consumed higher amounts of protein, particularly those from plant-based sources, in midlife had increased odds of aging healthily.
The findings of the latest paper, published in The American Journal of Clinical Nutrition, were based on an analysis of survey data collected every four years from 1984 to 2016 during the long-running Nurses' Health Study (NHS). The female healthcare workers involved were aged 38-59 in 1984 and deemed to be in good health, both physically and mentally, at the start of the study.
The survey data analyzed in the latest paper included information on how frequently people ate certain foods, which the authors used to calculate protein intake.
Joe Millward, a nutrition scientist with the University of Surrey in the U.K., who was not involved in the research, told Newsweek it was a "complicated study" of food intake in a large population of female nurses in the U.S.
Previous evidence has suggested that protein intake plays an important role in maintaining the health status of older adults. However, there has been a lack of epidemiological studies looking at the role of protein intake in midlife in relation to healthy aging in later life—the issue that the latest study explores.
"We decided to investigate this topic because the role of protein intake in the promotion of physical function had only been examined in the context of diets in older adulthood. However, we know that our dietary choices in midlife affect not only our physical ability in older adulthood, but also our risks for most major chronic diseases as well as for cognitive function," Andres Ardisson Korat, lead author of the study with the U.S. Department of Agriculture Human Nutrition Research Center on Aging, told Newsweek.
"Therefore, we set out to evaluate the associations of dietary protein and the primary sources of protein in middle adulthood with healthy aging considering four domains: chronic disease incidence, physical function, cognitive health, and mental status."
The results of the study showed that plant protein intake was favorably associated with several markers of health in older adults, including good physical function and mental health status.
However, it is important to note that the latest study was observational in nature, meaning that it was only able to identify associations between various forms of protein intake and healthy aging. As a result, it does not provide evidence of cause and effect.
Because of the observational nature of the study, the researchers also cannot exclude the possibility of unmeasured confounding factors that might have affected their results.
Other limitations of the study include the fact that it relied on self-reported questionnaires to assess the diet of the NHS participants. In addition, the researchers only looked at one specific population, consisting of (primarily white) female healthcare workers. This limits the generalizability of the findings to other populations.
As a result, the researchers said future research is warranted to verify these findings in other populations and to shed more light on the mechanisms underlying the associations between protein intake and healthy aging.
Nevertheless, the authors said their study contributes evidence to the role of protein in healthy aging, and adds specific insights into the importance of protein sources during relevant windows in midlife. The findings may contribute to providing recommendations regarding the amount of protein intake to promote healthy aging, they said.
"Consuming protein in midlife was linked to promoting good health in older adulthood," Korat said in a press release."We also found that the source of protein matters. Getting the majority of your protein from plant sources at midlife, plus a small amount of animal protein seems to be conducive to good health and good survival to older ages."
Update 1/22/24, 6:13 a.m. ET: This article has been updated with additional comments from Andres Ardisson Korat and Joe Millward.
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