A whey protein-based multi-ingredient nutritional supplement stimulates gains in lean body mass and strength in healthy older men: A randomized controlled trial

Abstract

Protein and other compounds can exert anabolic effects on skeletal muscle, particularly in conjunction with exercise. The objective of this study was to evaluate the efficacy of twice daily consumption of a protein-based, multi-ingredient nutritional supplement to increase strength and lean mass independent of, and in combination with, exercise in healthy older men. Forty-nine healthy older men (age: 73 ± 1 years [mean ± SEM]; BMI: 28.5 ± 1.5 kg/m2) were randomly allocated to 20 weeks of twice daily consumption of either a nutritional supplement (SUPP; n = 25; 30 g whey protein, 2.5 g creatine, 500 IU vitamin D, 400 mg calcium, and 1500 mg n-3 PUFA with 700 mg as eicosapentanoic acid and 445 mg as docosahexanoic acid); or a control (n = 24; CON; 22 g of maltodextrin). The study had two phases. Phase 1 was 6 weeks of SUPP or CON alone. Phase 2 was a 12 week continuation of the SUPP/CON but in combination with exercise: SUPP + EX or CON + EX. Isotonic strength (one repetition maximum [1RM]) and lean body mass (LBM) were the primary outcomes. In Phase 1 only the SUPP group gained strength (Σ1RM, SUPP: +14 ± 4 kg, CON: +3 ± 2 kg, P < 0.001) and lean mass (LBM, +1.2 ± 0.3 kg, CON: -0.1 ± 0.2 kg, P < 0.001). Although both groups gained strength during Phase 2, upon completion of the study upper body strength was greater in the SUPP group compared to the CON group (Σ upper body 1RM: 119 ± 4 vs. 109 ± 5 kg, P = 0.039). We conclude that twice daily consumption of a multi-ingredient nutritional supplement increased muscle strength and lean mass in older men. Increases in strength were enhanced further with exercise training.

Trial registration: ClinicalTrials.gov NCT02281331.

Conflict of interest statement

Competing Interests: The authors have read the journal's policy and the authors of this manuscript have the following competing interests: SMP reports receipt of competitive grant support, travel expenses, and honoraria for speaking received from the US National Dairy Council. No other conflicts of interest, financial or otherwise, are reported by any of the authors. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Figures

Fig 1. CONSORT flow diagram illustrating the movement of participants through the study, which was conducted between December 2014 and September 2016 (see S2 File. CONSORT Checklist).

Fig 2. Schematic of study design.

Participants consumed either a multi-ingredient protein-based nutritional supplement (SUPP) or control (CON) drink for 20 weeks total (from weeks 0–19, inclusive), and completed a 12 week exercise training program (RET twice per week and HIIT once per week) between weeks 7–18. Testing occurred at weeks -1 (baseline), 6, and 19, and included the following assessments: isotonic strength (1RM), aerobic fitness (VO2peak), physical function, body composition (DXA), and a 75g OGTT. Phase 1: SUPP/CON took place between weeks 0–6, and Phase 2: SUPP/CON + EX took place between weeks 7–19. 1RM, one repetition maximum; DXA, dual-energy x-ray absorptiometry; HIIT, high-intensity interval training; OGTT, oral glucose tolerance test; RET, resistance exercise training; VO2peak, peak oxygen uptake.

Fig 3

Isotonic strength expressed as the sum of all (A), upper body (B), and lower body (C) 1RMs. Boxes (SUPP: grey; CON: white) represent interquartile (25th to 75th percentile) ranges, with the horizontal lines indicating the median. Whiskers represent the maximal and minimal values, and the cross indicates the mean. Data were analyzed using a linear mixed model with group (SUPP or CON), time (prior to study entry, and weeks 6 and 19), and the group-by-time interaction as fixed factors; subject as a random factor; and baseline values as covariates. We observed significant group-by-time interactions for the sum of all 1RMs (P = 0.039) and for the sum of upper body 1RMs (P = 0.015), and a main effect of time for the sum of lower body 1RMs (P < 0.001). Dissimilar letters denote changes over time within a given treatment group (SUPP or CON). * Indicates a significant (P < 0.05) difference from the CON group at that time. 1RM, one repetition maximum; SUPP, supplement group (n = 25); CON, control group (n = 24).

Fig 4

Whole body (A), appendicular (B), and leg (C) lean mass over the course of the study. Boxes (SUPP: grey; CON: white) represent interquartile (25th to 75th percentile) ranges, with the horizontal lines indicating the medians. Whiskers represent the maximal and minimal values, and the crosses indicate the means. Data was analyzed using a linear mixed model with group (SUPP or CON), time (prior to study entry, and weeks 6 and 19), and the group-by-time interaction as fixed factors; subject as a random factor; and baseline values as covariates. We observed significant group-by-time interactions for whole body (P < 0.01), appendicular (P = 0.021), and leg lean mass (P = 0.015). Dissimilar letters denote changes over time within a given treatment group (SUPP or CON). SUPP, supplement group (n = 25); CON, control group (n = 24).