Nutritional predictors of muscle protein metabolism and function in older adults

Abstract

Sarcopenia contributes to frailty in older adults and is associated with alterations in muscle protein metabolism. The purpose of this research was to examine the potential predictors of muscle protein synthesis and function in elders.MethodsWe report preliminary data from a subset of 8 healthy, sedentary subjects (69.5±3.4 yrs, BMI ≤30kg·m−2) enrolled in a larger study who met their dietary requirements. Linear regressions were carried out on the following variables: muscle protein fractional synthetic rate (FSR), muscle function tests, VO2peak, daily step count, dual energy x‐ray absorbometry (DEXA), 3‐day food diary, and blood biochemical analyses.ResultsThe best linear regressors of FSR were soluble fiber (R2=−0.59, P=0.03) and vitamin D intake (R2=0.60, P=0.01). The best multiple regressors were soluble fiber and leucine intake (R2=0.85, P=0.009). When the subjects were divided by BMI into overweight (n=4) or normal weight (n=4), the overweight subjects had a lower relative lean body weight (62.2±6.2% vs. 70.4±8.3) and slower 20‐meter load carry with weight time (11.4±2.2 sec vs. 10.9±1.1).SummaryIn a group of healthy older adults who are meeting their recommended nutritional requirements, dietary factors influence FSR. Further, overweight subjects have additional negative health and functional outcomes. This study was supported by NIH R01 AG030070 and P30 AG024832.