Relationship between total protein intake and essential amino acid threshold frequency on measures of muscle mass in adults between 50-80 years of age
Sarcopenia, loss of skeletal muscle in older adults, can lead to serious health consequences. Several non-pharmacological strategies have been suggested to prevent sarcopenia, one of which is increased protein consumption above the current RDA and/or reaching a certain threshold (approximately equal to 10 grams of essential amino acids) of quality protein at each meal. This study examined the association between the amount of skeletal muscle mass in older active adults with regard to their total protein intake and essential amino acid threshold frequency (EAATF) (number of meals per day that provided at least 10 grams of essential amino acids). Fifty-one healthy male (n=22) and female (n=29) active older adults participated in this cross-sectional study. Average daily total protein (grams) and EAATF were determined from a seven-day dietary record. Dietary records and subsequent amino acid profiling were analyzed using a computer software program. Daily food records were averaged across seven-days to give an average representation of total protein intake and EAATF. Total and appendicular lean mass (aLM) were determined by Dual Energy X-Ray Absorptiometry (DXA). Relative lean mass (RLM, total lean mass/height2) and appendicular lean mass index (aLM/height2) were also calculated. Data were analyzed using Pearson Partial Correlation Coefficients controlling for body weight and physical activity level with an alpha level of 0.05. EAATF (1.1 + 0.6 times/day) was positively associated with RLM (r = 0.621, p < 0.001) as well as aLM index (r = 0.583, p < 0.001). Total protein intake (91.1 + 29.1) was also positively associated with RLM (r = 0.582, p < 0.001) and aLM index (r = 0.598, p < 0.001). Our data suggest that, not only total protein intake, but also consuming a certain threshold of quality protein with each meal throughout a day may be important for maintaining muscle mass during aging.
Thesis (M.Ed.)--Wichita State University, College of Education, Dept. of Human Performance Studies