This study investigates the relationship between dietary protein intake in midlife and healthy aging among female participants in the Nurses' Health Study (NHS) cohort. The researchers analyzed data from 48,762 participants aged <60 years in 1984, focusing on total protein, animal protein, dairy protein, and plant protein intake. Healthy aging was defined as being free from 11 major chronic diseases, having good mental health, and no impairments in cognitive or physical function. Using multivariate logistic regression, they found that higher protein intake was significantly associated with higher odds of healthy aging, with plant protein showing the strongest positive association. Plant protein intake was also linked to better physical function and mental health. Substitution analyses showed that replacing animal or dairy protein with plant protein was associated with better odds of healthy aging. The study concludes that dietary protein intake, particularly plant protein, in midlife is associated with higher odds of healthy aging and positive health status in older adults.This study investigates the relationship between dietary protein intake in midlife and healthy aging among female participants in the Nurses' Health Study (NHS) cohort. The researchers analyzed data from 48,762 participants aged <60 years in 1984, focusing on total protein, animal protein, dairy protein, and plant protein intake. Healthy aging was defined as being free from 11 major chronic diseases, having good mental health, and no impairments in cognitive or physical function. Using multivariate logistic regression, they found that higher protein intake was significantly associated with higher odds of healthy aging, with plant protein showing the strongest positive association. Plant protein intake was also linked to better physical function and mental health. Substitution analyses showed that replacing animal or dairy protein with plant protein was associated with better odds of healthy aging. The study concludes that dietary protein intake, particularly plant protein, in midlife is associated with higher odds of healthy aging and positive health status in older adults.