Native Whey Induces Similar Post Exercise Muscle Anabolic Responses as Regular Whey, Despite Greater Leucinemia, in Elderly Individuals.

OBJECTIVE: Elderly muscle seems less sensitive to the anabolic stimulus of a meal. Changes in blood concentrations of leucine are suggested as one important trigger of the anabolic response in muscle. The aim of this study was to investigate whether native whey protein, containing high amounts of leucine, may be a more potent stimulator of muscle protein synthesis (MPS) in elderly than regular whey protein (WPC-80) or milk. DESIGN: Randomized controlled partial crossover. SETTING: Norwegian School of Sport Sciences. PARTICIPANTS: 21 healthy elderly men and women (≥70 years). INTERVENTION: Participants received either 20 g of WPC-80 and native whey (n = 11) on separate days in a crossover design, or milk (n = 10). Supplements were ingested immediately and two hours after a bout of lower body heavy-load resistance exercise. MEASUREMENTS: Blood samples and muscle biopsies were collected to measure blood concentrations of amino acids by gas-chromatography mass spectrometry (GCMS), phosphorylation of p70S6K, 4E-BP1 and eEF-2 by immunoblotting and mixed muscle fractional synthetic rate (FSR) by use of [2H5]phenylalanine-infusion, GCMS and isotope-ratio mass spectrometry. RESULTS: Native whey increased blood leucine concentrations more than WPC-80 (P < 0.05), but not p70S6K phosphorylation or mixed muscle FSR. Both whey supplements increased blood leucine concentrations (P < 0.01) and P70S6K phosphorylation more than milk (P = 0.014). Native whey reached higher mixed muscle FSR values than milk (P = 0.026) 1-3h after exercise. CONCLUSIONS: Despite greater increases in blood leucine concentrations than WPC-80 and milk, native whey was only superior to milk concerning increases in MPS and phosphorylation of P70S6K during a 5-hour post-exercise period in elderly individuals.

Intake of a Protein-Enriched Milk and Effects on Muscle Mass and Strength. A 12-Week Randomized Placebo Controlled Trial among Community-Dwelling Older Adults.

OBJECTIVES: To investigate the effect of 20 g protein with breakfast and evening meal on muscle mass, muscle strength and functional performance in older adults. DESIGN: A double-blinded randomized controlled study. SETTING: Oslo and Akershus University College of Applied Sciences, Norway. PARTICIPANTS: Healthy community-dwelling men and women (≥ 70 years) with reduced physical strength and/or performance. INTERVENTION: Subjects were randomly assigned to receive either protein-enriched milk (2 x 0.4 L/d; protein group) or an isocaloric carbohydrate drink (2 x 0.4 L/d; control group) with breakfast and evening meal for 12 weeks. MEASUREMENTS: The primary endpoints were muscle mass measured by dual X-ray absorptiometry, and tests of muscle strength (one repetition maximum test of chest press and leg press) and functional performance (handgrip strength, stair calimb and repeated chair rise). RESULTS: In total, 438 subjects were screened, 50 subjects were randomized and 36 completed the study. Chest press improved significantly in the protein (1.3 kg (0.1-2.5), p=0.03) and the control group (1.5 kg (0.0-3.0), p=0.048), but with no difference between the groups (p=0.85). No significant change in leg press (p=0.93) or muscle mass (p=0.54) were observed between the protein and the control group. Nor did we observe any significant differences in the functional performance tests (p>0.05 for all tests) between the groups. CONCLUSION: Increased protein intake (2 x 20 g/d) did not significantly improve muscle mass, muscle strength or functional performance in healthy older weight stable adults. Whether intake of > 20 g protein to each meal is necessary for preservation of muscle mass and strength in older adults should be further investigated in a larger study. This underscores the need for well-designed studies that can differentiate between the effect of protein intake and increased energy. This trial was registered at Clinicaltrials.gov (ID no. NCT02218333).

Vitamin C and E supplementation alters protein signalling after a strength training session, but not muscle growth during 10 weeks of training.

This study investigated the effects of vitamin C and E supplementation on acute responses and adaptations to strength training. Thirty-two recreationally strength-trained men and women were randomly allocated to receive a vitamin C and E supplement (1000 mg day(-1) and 235 mg day(-1), respectively), or a placebo, for 10 weeks. During this period the participants' training involved heavy-load resistance exercise four times per week. Muscle biopsies from m. vastus lateralis were collected, and 1 repetition maximum (1RM) and maximal isometric voluntary contraction force, body composition (dual-energy X-ray absorptiometry), and muscle cross-sectional area (magnetic resonance imaging) were measured before and after the intervention. Furthermore, the cellular responses to a single exercise session were assessed midway in the training period by measurements of muscle protein fractional synthetic rate and phosphorylation of several hypertrophic signalling proteins. Muscle biopsies were obtained from m. vastus lateralis twice before, and 100 and 150 min after, the exercise session (4 × 8RM, leg press and knee-extension). The supplementation did not affect the increase in muscle mass or the acute change in protein synthesis, but it hampered certain strength increases (biceps curl). Moreover, increased phosphorylation of p38 mitogen-activated protein kinase, Extracellular signal-regulated protein kinases 1 and 2 and p70S6 kinase after the exercise session was blunted by vitamin C and E supplementation. The total ubiquitination levels after the exercise session, however, were lower with vitamin C and E than placebo. We concluded that vitamin C and E supplementation interfered with the acute cellular response to heavy-load resistance exercise and demonstrated tentative long-term negative effects on adaptation to strength training.