Publication: Ardisson Korat AV, Shea MK, Jacques PF, et al. Dietary protein intake in midlife in relation to healthy aging – results from the prospective Nurses' Health Study cohort.
Am J Clin Nutr. 2023;119(2):271-282. PMID: 38309825
Reviewer: Danial Nadeem, MD, DABOM, CNSC
Why is This Paper Important: As the global population ages, identifying dietary factors that promote healthy aging is crucial. Aging is a complex process influenced by genetic, environmental, and lifestyle factors, among which nutrition plays a pivotal role. In particular, protein intake has long been recognized as essential for maintaining muscle mass, metabolic health, and immune function, all of which decline with age. However, while the importance of protein intake in preventing frailty and sarcopenia in older adults is well recognized, less is known about how protein consumption earlier in life—particularly during midlife—affects aging outcomes.
This study investigated the association between midlife dietary protein consumption and subsequent healthy aging, providing insights that could inform nutritional guidelines and interventions aimed at improving quality of life in older adults.
Summary: This prospective cohort study analyzed data from 48,762 female participants in the Nurses' Health Study, focusing on their dietary protein intake during midlife and its relation to healthy aging outcomes later in life. Healthy aging was defined as survival to age 70 or older without major chronic diseases, cognitive impairment, physical disabilities, or mental health limitations. Dietary assessments were conducted using validated food frequency questionnaires, and protein intake was categorized into total, animal, and plant-based sources. The findings revealed that higher total protein intake was significantly associated with greater odds of healthy aging. Specifically, the odds ratios (ORs) per 3% energy increment were 1.05 (95% CI: 1.01, 1.10) for total protein, 1.07 (95% CI: 1.02, 1.11) for animal protein, and 1.38 (95% CI: 1.24, 1.54) for plant protein. These associations remained significant after adjusting for various lifestyle and dietary factors. Notably, plant protein intake was also associated with higher odds of absence of physical function limitations and good mental status. Substitution analyses indicated that replacing animal or dairy protein, carbohydrates, or fats with plant protein was associated with higher odds of healthy aging, with ORs ranging from 1.22 to 1.58 for a 3% energy replacement with plant protein.
Higher total protein intake was linked to a lower incidence of chronic diseases, including cardiovascular disease and type 2 diabetes, while also being associated with better preservation of cognitive and physical function. The analysis further confirmed that protein intake remained beneficial even after accounting for potential confounders, including BMI, physical activity levels, and overall diet quality. Sensitivity analyses supported the robustness of these findings, indicating that the associations were consistent across different population subgroups within the study cohort. The authors concluded that increasing protein intake during midlife may be an effective dietary strategy to support healthier aging outcomes and reduce the risk of age-related functional decline.
Commentary: This study contributes valuable evidence to the discourse on dietary protein's role in promoting healthy aging. The positive association between higher midlife protein intake and favorable aging outcomes underscores the importance of adequate protein consumption during midlife as a potential strategy to enhance long-term health. Protein plays a crucial role in maintaining muscle mass, metabolic function, and overall physiological resilience, all of which are important for reducing the risk of age-related decline. The study’s findings suggest that prioritizing sufficient protein intake during midlife may help preserve cognitive function, prevent chronic diseases, and support better physical health later in life.
One of the key strengths of this study is its large and well-characterized cohort, allowing for robust statistical adjustments to control for confounding variables. However, the cohort consisted predominantly of health-conscious female nurses, which may limit the generalizability of the findings to men and individuals from different racial, socioeconomic, and lifestyle backgrounds. Additionally, the study design is observational, meaning causality cannot be established. Future research should focus on more diverse populations and mechanistic studies to explore the biological pathways through which protein intake influences aging. Understanding these relationships further could help refine dietary guidelines aimed at improving longevity and quality of life in aging populations.
References:
- Ardisson Korat AV, Shea MK, Jacques PF, et al. Dietary protein intake in midlife in relation to healthy aging – results from the prospective Nurses' Health Study cohort. Am J Clin Nutr. 2023;119(2):271-282. PMID: 38309825
- Coelho-Júnior HJ, Calvani R, Toscanelli F, et al. Association between dietary protein intake and changes in health status in older adults: a systematic review and meta-analysis. BMC Geriatr. 2021;21(1):231. PMID: 33957860
- Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc. 2013;14(8):542-559. PMID: 23867520
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