Table 3.
Placebo-Controlled Randomized Trials Reporting the Effects of Protein Supplementation on Muscle Mass, Strength and/or Physical Performance among adults over 65*
| Supplement Type |
Dose | Reference | Study Population | Duration | Muscle Mass Outcomes* |
Muscle Strength Outcomes |
Physical Performance Outcomes |
|---|---|---|---|---|---|---|---|
| Milk protein | 2 15-g (MPC80; milk protein concentrate), 7.1 g lactose, 0.5g fat, 0.4 g calcium or matching placebo (Friesland) | Tieland 201231 | 65 frail men and women aged 65 and older | 24 wk | DXA (NS) | Leg-press, leg-extension (NS) | SPPB (↑) |
| Leucine | 7.5g/d L-Leucine (Frutarom) or placebo (wheat flour; Verstegen) as capsules with meals | Leenders 201149 | 60 men with type 2 diabetes (mean age 71±1y) | 24 wk | DXA (NS) | Leg-press, leg-extension (↑ Frutaro) | NA |
| 7.5 g/d L-Leucine (Ajinomoto) or placebo (wheat flour; Verstegen) as capsules with meals | Verhoeven et al 200950 | 30 healthy men (mean age 71±4y) | 12 wk | DXA (NS) | Leg-press, leg-extension (NS) | NA | |
| Juven** | Juven** vs NEAA powder with breakfast | Baier 200943 | 129 men and women from senior centers | 1 yr | BIA (FFM ↑ with Juven) and DXA (NS) | Knee extension; hand grip (NS) | Get-up-and-Go (NS) |
| Juven** vs NEAA powder with breakfast | Flakoll 200451 | 29 women in study 1 (age 65–90); 28 women in study 2 (62 to 85) | 12 wk | BIA (NS) | Knee extension (↑); hand grip (↑) | Get-up-and-Go ↑ | |
| EAA | 2 7.5g EAA or placebo capsules | Dillon 200933 | 14 women (mean age 69) | 12 wk | DXA ↑ | Knee extension; hand grip (NS) | NA |
Includes studies having a placebo control group, targeting prevention of sarcopenia (rather than treatment), and involved nutrition intervention alone (rather than in combination with exercise).
Juven is comprised of HMB (CaHMB, 2 or 3 g), L-arginine (5 or 7.5 g), L-lysine (lysine HCl, 1.5 or 2.25 g), and ascorbic acid (0.1 g).Participants were assigned to the lower or higher dose based on a weight cutpoint (68 kg). The control group received a similar orange-tasting isonitrogenous and isocaloric drink consisting of a mixture of nonessential amino acids (alanine 5.6 g, glutamic acid 0.9 g,glycine 3.1 g, serine 2.2 g and containing 0.1 g of ascorbic acid, and matched with the treatment based on net weight of the packet content
Abbreviations: ↑ or NS (non-significant)= intervention compared to controls ;AA=amino acid supplement; BIA= Bioelectrical impedance analysis; DXA= dual x-ray absorpitmetry ; EAA=essential amino acid; E=Exercise; FFM=fat free mass; NA=not applicable; SPPB: Short Physical Performance Battery