Dietary protein intake in midlife in relation to healthy aging – results from the prospective Nurses’ Health Study cohort

Authors: ARDISSON KORAT, ANDRES - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; SHEA, KYLA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; JACQUES, PAUL - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; SEBASTIANI, PAOLA - Tufts Medical Center; WANG, MOLIN - Harvard University; ELIASSEN, HEATHER - Brigham & Women'S Hospital; WILLETT, WALTER - Harvard University; SUN, QI - Harvard University

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/6/2023
Publication Date: 2/1/2024
Citation: Ardisson Korat, A., Shea, K., Jacques, P.F., Sebastiani, P., Wang, M., Eliassen, H., Willett, W.C., Sun, Q. 2024. Dietary protein intake in midlife in relation to healthy aging – results from the prospective Nurses’ Health Study cohort. The American Journal of Clinical Nutrition. https://doi.org/10.1016/j.ajcnut.2023.11.010.
DOI: https://doi.org/10.1016/j.ajcnut.2023.11.010

Interpretive Summary: Protein intake plays an important role in maintaining the health status of older adults, especially for physical function. However, few studies have evaluated the role of protein consumption and protein sources during middle adulthood in healthy aging. We observed in a large cohort of women that dietary protein intake, especially plant protein, in midlife was associated with better odds of healthy aging and with several components of positive health status in a large cohort of women. Furthermore, we observed that replacing animal or dairy protein, carbohydrate, or fat with plant protein was associated with better odds of healthy aging, and with higher likelihood of being free of chronic diseases, having good mental health, and not having impairments in either cognitive or physical function. Our study suggests that protein intake, especially from plant-based sources, may play a role in maintaining health status at older ages.

Technical Abstract: Protein intake plays an important role in maintaining the health status of older adults. However, few epidemiological studies examined midlife intake of protein in relation to healthy aging. The objective of our study was to evaluate the long-term role of dietary protein intake in healthy aging among women in the Nurses' Health Study (NHS). We included 48,762 NHS participants aged <60 years old in 1984. Total protein, animal protein, dairy protein, and plant protein were derived from validated food-frequency questionnaires. Healthy aging was defined as being free from 11 major chronic diseases, having good mental health, and not having impairments in either cognitive or physical function as assessed in the 2014 or 2016 NHS participant questionnaires. We used multivariate logistic regression to estimate the odds ratios (ORs) and 95% confidence intervals (CI) for protein intake in relation to healthy aging. A total of 3,721 (7.6%) NHS participants met our healthy aging definition. Protein intake was significantly associated with higher odds of healthy aging. The ORs (95% CIs) per 3%-energy increment with healthy aging were 1.05 (1.01, 1.10) for total protein, 1.07 (1.02, 20 1.11) for animal protein, 1.10 (1.03, 1.18) for dairy protein, and 1.38 (1.24, 1.54) for plant protein. Plant protein was also positively associated with individual components of the healthy aging phenotype. In substitution analyses, we observed significant positive associations for the isocaloric replacement of animal or dairy protein, carbohydrate, or fat with plant protein (ORs for healthy aging: 1.22 to 1.55 for 3% energy replacement with plant protein). Dietary protein intake, especially plant protein, in midlife was associated with better odds of healthy aging and with several domains of positive health status in a large cohort of women. These data suggest that protein intake, especially from plant-based sources, may play a role in maintaining health status at older ages.