Effect of Intake of Leucine-Rich Protein Supplement on the Body Composition and Function of Healthy Adults

Research Objectives: This study aimed to evaluate the effects of daily resistance exercise combined with daily intake of accessible leucine-rich protein supplements on the body composition and physical function of healthy adults.

Design: A prospective randomized double blinded pilot study for 12 weeks follow-up.

Setting: Gil Hospital in Incheon and at Incheon University Sports Center.

Participants: The study analyzed 50 healthy people without medical conditions, who were randomly assigned to two groups (taking either protein powder or placebo powder) twice a day for 12 weeks.

Interventions: All participants performed resistance exercises regularly that could be repeated 8–12 times using a thera-band for 12 weeks. A total of 41 participants completed the study.

Main Outcome Measures: Body composition was measured using bioimpedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA). Inbody-720 was used for BIA analysis. Using a dynamometer, grip strength (kg) was measured twice in the right and left hands, and the maximum value was recorded. The senior fitness test (SFT) was performed to measure the physical performance of the participants before and after the start of the study .

Results: The lean body mass (LBM) and skeletal muscle mass (SMM) change measured via bioimpedance analysis (BIA) was significantly greater in the protein powder group than in the placebo powder group (LBM: 0.95 ± 0.91 kg in the protein powder group vs. 0.38 ± 1.06 kg in the placebo powder group, p = 0.043; SMM: 0.69 ± 0.58 kg in the protein powder group vs. 0.29 ± 0.65 kg in the placebo powder group, p = 0.039, respectively). In the senior fitness test (SFT), significant functional improvement was found within the two groups, but no significant difference was found between the groups in the degree of improvement.

Conclusions: in older people aged >50, to prevent sarcopenia, is more effective to combine resistance exercise and leucine-rich protein supplementation than to simply perform resistance exercise.

Author(s) Disclosures: The authors declare no conflicts of interest.