Year‐long Changes in Protein Metabolism in Elderly Men and Women Supplemented With a Nutrition Cocktail of β‐Hydroxy‐β‐methylbutyrate (HMB), L‐Arginine,and L‐Lysine

Background: A major contributing factor to the loss of mobility in elderly people is the gradual and continuous loss of lean body mass. Objectives: To determine whether supplementation of an amino acid cocktail daily for 1 year could improve the age‐associated changes in protein turnover and lean body mass in elderly people. Design: Elderly (76± 1.6 years) women (n = 39) and men (n = 38) were recruited for a double‐blinded controlled study. Study participants were randomly assigned to either an isonitrogenous control‐supplement (n = 37) or a treatment‐supplement (HMB/Arg/Lys) consisting of β‐hydroxy‐β‐methylbutyrate, L‐arginine, and L‐lysine (n = 40) for the 1‐year study. Lean tissue mass was measured using both bioelectrical‐impedance analysis (BIA) and dual energy x‐ray absorptiometry (DXA). Rates of whole‐body protein turnover were estimated using primed/intermittent oral doses of ¹⁵N‐glycine. Results: In subjects taking the HMB/Arg/Lys supplement, lean tissue increased over the year of study while in the control group, lean tissue did not change. Compared with control, HMB/Arg/Lys increased body cell mass (BIA) by 1.6% (P = .002) and lean mass (DXA) by 1.2% (P = .05). The rates of protein turnover were significantly increased 8% and 12% in the HMB/Arg/Lys‐supplemented group while rates of protein turnover decreased 11% and 9% in the control‐supplemented subjects (P < .01), at 3 and 12 months, respectively. Conclusions: Consumption of a simple amino acid‐related cocktail increased protein turnover and lean tissue in elderly individuals in a year‐long study.