Protein supplementation improves lean body mass in physically active older adults: a randomized placebo-controlled trial.
Study Goal
The researchers aimed to determine whether daily protein supplementation could enhance lean body mass, muscle strength, and physical performance in physically active older adults with low habitual protein intake during walking exercise training.
Results Summary
Protein supplementation led to a larger increase in relative lean body mass and a greater reduction in fat mass compared to placebo, though no differences were observed in muscle strength or physical performance improvements between groups. Walking exercise training alone improved physical performance, lean body mass, and reduced fat mass.
Population
Physically active older adults (median age 69, 82% male) training for a multi-day walking event with low habitual protein intake (<1.0 g/kg/day).
Effective Dosage
31 g of milk protein daily
Duration
12 weeks
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
12 weeks of daily protein supplementation | increase | relative lean body mass | physically active older adults with a low habitual protein intake (<1.0 g/kg/day) | ∆0.93 ± 1.22% vs. ∆0.44 ± 1.40% | A larger increase in relative lean body mass was observed | #1 |
12 weeks of daily protein supplementation | decrease | fat mass | physically active older adults with a low habitual protein intake (<1.0 g/kg/day) | - | a larger reduction in fat mass were observed | #2 |
12 weeks of daily protein supplementation | no change | muscle strength | physically active older adults with a low habitual protein intake (<1.0 g/kg/day) | - | no differences in improvements between groups | #3 |
12 weeks of daily protein supplementation | no change | physical performance | physically active older adults with a low habitual protein intake (<1.0 g/kg/day) | - | no differences in improvements between groups | #4 |
walking exercise training | increase | physical performance | physically active older adults with relatively low habitual dietary protein consumption | - | an improvement in physical performance were observed | #5 |
walking exercise training | increase | lean body mass | physically active older adults with relatively low habitual dietary protein consumption | - | an increase in lean body mass were observed | #6 |
walking exercise training | decrease | fat mass | physically active older adults with relatively low habitual dietary protein consumption | - | a decrease in fat mass were observed | #7 |
BACKGROUND: An inadequate protein intake may offset the muscle protein synthetic response after physical activity, reducing the possible benefits of an active lifestyle for muscle mass. We examined the effects of 12 weeks of daily protein supplementation on lean body mass, muscle strength, and physical performance in physically active older adults with a low habitual protein intake (<1.0 g/kg/day). METHODS: A randomized double-blinded controlled trial was performed among 116 physically active older adults [age 69 (interquartile range: 67-73) years, 82% male] who were training for a 4 day walking event of 30, 40, or 50 km/day. Participants were randomly allocated to either 31 g of milk protein or iso-caloric placebo supplementation for 12 weeks. Body composition (dual-energy X-ray absorptiometry), strength (isometric leg extension and grip strength), quadriceps contractile function, and physical performance [Short Physical Performance Battery, Timed Up-and-Go test, and cardiorespiratory fitness (Åstrand-Rhyming submaximal exercise test)] were measured at baseline and after 12 weeks. We assessed vitamin D status and markers of muscle damage and renal function in blood and urine samples before and after intervention. RESULTS: A larger increase in relative lean body mass was observed in the protein vs. placebo group (∆0.93 ± 1.22% vs. ∆0.44 ± 1.40%, P CONCLUSIONS: In physically active older adults with relatively low habitual dietary protein consumption, an improvement in physical performance, an increase in lean body mass, and a decrease in fat mass were observed after walking exercise training. A larger increase in relative lean body mass and larger reduction in fat mass were observed in participants receiving 12 weeks of daily protein supplementation compared with controls, whereas this was not accompanied by differences in improvements between groups in muscle strength and physical performance.