Protein metabolism in women and men: Similarities and disparities

Purpose of review: To provide an objective and comprehensive review of the recent literature addressing the effects of sex on protein metabolism. We also evaluate whether these differences can be attributed to physiology or methodology. Because of the developmental changes in hormonal milieu and body composition that occur across life, the literature has been examined in a longitudinal manner across the lifespan. Recent findings: Throughout most points of life, men and women of similar health status and BMI display fairly similar protein turnover rates. However, some investigators have reported sexual dimorphism in protein metabolism, which may be partly attributable to differences in fat-free mass and/or methodology. In periods of significant changes in the hormonal milieu (puberty and menopause), sex differences may become more evident. Finally, anabolic stimuli such as feeding and exercise may help highlight any discrepancies in protein turnover between men and women. Summary: Sex differences in protein metabolism, if any, are most evident during the main phases of hormonal changes, and may be also due to differences in body composition. However, methodological issues and sample size must be considered when designing and evaluating these studies.