The effect of daily protein supplementation, with or without resistance training for 1 year, on muscle size, strength, and function in healthy older adults: A randomized controlled trial.
Study Goal
The researchers aimed to determine whether collagen protein supplementation, alone or combined with resistance training, could improve muscle size, strength, and function in older adults compared to carbohydrate supplementation or whey protein.
Results Summary
Collagen supplementation (COLL) showed no significant effects on quadriceps cross-sectional area, lower extremity strength, power, or functional capabilities compared to carbohydrate supplementation (CARB). It was also ineffective relative to whey protein (WHEY).
Population
Healthy older adults (>65 years)
Effective Dosage
20 g collagen protein + 10 g carbohydrate, twice daily
Duration
1 year
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
collagen protein supplementation | no change | any measured parameter | healthy older adults (>65 y) | - | did not affect | #1 |
whey protein supplementation | no change | any measured parameter | healthy older adults (>65 y) | - | did not affect | #2 |
heavy resistance training 3 times weekly with whey protein supplementation | increase | quadriceps cross-sectional area size | healthy older adults (>65 y) | +1.68 cm2 | improved | #3 |
heavy resistance training 3 times weekly with whey protein supplementation | increase | dynamic knee extensor strength | healthy older adults (>65 y) | +18.4 Nm | improved | #4 |
heavy resistance training 3 times weekly with whey protein supplementation | increase | isometric knee extensor strength | healthy older adults (>65 y) | +23.9 Nm | improved | #5 |
light-intensity resistance training 3-5 times/wk with whey protein supplementation | no change | quadriceps cross-sectional area size | healthy older adults (>65 y) | - | did not improve | #6 |
light-intensity resistance training 3-5 times/wk with whey protein supplementation | increase | dynamic knee extensor strength | healthy older adults (>65 y) | +13.7 Nm | increased | #7 |
BACKGROUND: Protein supplementation alone or combined with resistance training has been proposed to be effective in counteracting age-related losses of muscle mass and strength. OBJECTIVES: To investigate the effect of protein supplementation alone or combined with light-intensity or heavy-load resistance exercise on muscle size, strength, and function in older adults. METHODS: In a 1-y randomized controlled trial, 208 healthy older adults (>65 y) were randomly assigned to 1 of 5 interventions: 1) carbohydrate supplementation (CARB); 2) collagen protein supplementation (COLL); 3) whey protein supplementation (WHEY); 4) light-intensity resistance training 3-5 times/wk with whey protein supplementation (LITW); and 5) heavy resistance training 3 times weekly with whey protein supplementation (HRTW). Protein supplements contained 20 g protein + 10 g carbohydrate, whereas CARB contained 30 g of carbohydrates. All intervention groups received the supplement twice daily. The primary outcome was change in the quadriceps cross-sectional area (qCSA). Secondary outcomes included measures of lower extremity strength and power, functional capabilities, and body composition. RESULTS: There were 184 participants who completed the study. COLL and WHEY did not affect any measured parameter compared to CARB. Compared to WHEY, HRTW improved the qCSA size (between-group difference, +1.68 cm2; 95% CI, +0.41 to +2.95 cm2; P = 0.03), as well as dynamic (+18.4 Nm; 95% CI, +10.1 to +26.6 Nm; P < 10-4) and isometric knee extensor strength (+23.9 Nm; 95% CI, +14.2 to +33.6 Nm; P < 10-5). LITW did not improve the qCSA size, but increased dynamic knee extensor strength compared to WHEY (+13.7 Nm; 95% CI, +5.3 and +22.1 Nm; P = 0.01). CONCLUSIONS: Recommending protein supplementation as a stand-alone intervention for healthy older individuals seems ineffective in improving muscle mass and strength. Only HRTW was effective in both preserving muscle mass and increasing strength. Thus, we recommend that future studies investigate strategies to increase long-term compliance to heavy resistance exercise in healthy older adults. This trial was registered at clinicaltrials.gov as NCT02034760.