Sarcojoint®, the branched-chain amino acid-based supplement, plus resistance exercise improved muscle mass in adults aged 50 years and older: A double-blinded randomized controlled trial

Functional ability and intrinsic capacity are key elements of healthy aging, in which exercise and good nutrition play important roles. This 12-week double-blinded randomized controlled trial enrolled community-dwelling adults aged 50 years and older to examine the effects of Sarcojoint®, a comprehensive formula for the musculoskeletal system, plus resistance exercise on muscle mass. This study intended to enroll 80 participants with a randomly selected subsample of 32 participants (16 from the intervention group and 16 from controls) for magnetic resonance imaging (MRI) to assess the cross-sectional area of the bilateral mid-thighs. The participants were then randomly assigned to the intervention group (Sarcojoint® 1 package twice a day) and control group (vitamin B as placebo) at a 1: 1 ratio. All the participants were required to undergo a regular exercise program (45 min at the gym per week and two sessions of 30-min exercise at home). The data from 66 participants (68.1 ± 7.1 years and 16.7% males; intervention group: 32, control group: 34) were available for analysis. The whole study was pre-registered and data reporting followed Consolidated Standards of Reporting Trials with the primary endpoints of muscle mass, 30-s chair-rise test, and gait speed. Results of MRI were the subgroup analysis to examine muscle mass and intramuscular adiposity. The baseline characteristics of all the participants between groups were similar, as well as those of the MRI subgroups. Within-group comparisons showed that the intervention group, but not the control group, significantly reduced the total body fat percentage (34.3 ± 5.5 vs. 35.0 ± 5.4%, P = 0.021). Serum vitamin D was increased in the intervention group (24.1 ± 6.1 vs. 21.1 ± 7.0 ng/mL; P = 0.025) and was reduced in the control group (18.0 ± 5.2 vs. 20.2 ± 5.8 ng/mL; P = 0.006). The physical performance tests of both groups were significantly improved. The between-group analysis showed no significant differences in 30-s chair stand test, handgrip strength and appendicular muscle mass. The sub-group analysis showed significant improvement in the serum levels of vitamin D (6.70 ± 8.20 vs. -0.50 ± 3.90 ng/mL; P = 0.001) and the mid-thigh cross-sectional area of the nondominant legs (165.4 ± 291.4 vs. -61.1 ± 195.0 mm2; P = 0.034) in the intervention group. In conclusion, Sarcojoint® plus resistance exercise significantly increased muscle mass and serum levels of vitamin D, but not significantly better in muscle strength and physical performance than controls. More investigations are needed to evaluate the long-term effects of Sarcojoint® on middle-aged and older adults.