Number of high-protein containing meals correlates with muscle mass in pre-frail and frail elderly

Background Aging is accompanied by the inability to optimally respond to anabolic stimulus of nutrition, with consequent loss of muscle mass and functionality. It has been speculated that not only total protein intake, but also the per meal protein dose may have important implications to protein balance and, hence, muscle mass in middle-aged and older adults, but evidence is lacking in a more vulnerable population such as the frail elderly. The aim was to investigate possible associations between total protein intake and its per meal dose with multiple measures of muscle mass, strength, and functionality in a cohort of pre-frail and frail elderly individuals. Methods One-hundred-and-fifty-seven pre-frail and frail elderly individuals were assessed for total and per meal protein intake (food diaries), total and appendicular lean mass (DXA), vastus lateralis cross-sectional area [(CSA) B-mode ultrasound], and muscle function [leg-press and bench press 1-RM, timed-stands test, timed-up-and-go test, handgrip, and risk of falls (Biodex Balance System (R))]. Results Protein intake and number of meals with either >= 20 g or >= 30 g of protein were significantly associated (after controlling for confounding factors) with greater total and appendicular lean mass and vastus lateralis CSA. Conclusions We found that not only total protein intake but also the number of high-protein containing meals are associated with muscle mass in frail and pre-frail elderly.