Digital Commons Network^™

Whole-Body And Muscle Protein Metabolism Are Not Affected By Acute Deviations From Habitual Protein Intake In Older Men: The Hormonal Regulators Of Muscle And Metabolism In Aging (Horma) Study, Kevin E. Yarasheski, Carmen Castaneda-Sceppa, Jiaxiu He, Miwa Kawakubo, Shalender Bhasin, Ellen F. Binder, E. Todd Schroeder, Ronenn Roubenoff, Stan P. Azen, Fred R. Sattler

Carmen Castaneda-Sceppa

Background: Acute deviations in protein intake before the quantification of protein kinetics in older humans may explain the controversy over the effects of older age on muscle protein synthesis and proteolysis rates. Objective: We hypothesized that an acute decrease in protein intake from the habitual intake is associated with lower muscle protein synthesis and higher proteolysis rates, whereas an acute increase in protein intake from the habitual intake is associated with higher muscle protein synthesis and lower proteolysis rates. Design: In 112 community-dwelling healthy men aged 65–90 y, we quantified resting whole-body [1,2-13C2]leucine kinetics, muscle mixed protein fractional synthesis rates …