attenuate muscle disruption and optimize changes in body composition, but this practice may not have a meaningful effect on performance compared with the ingestion of carbohydrate alone ( McLellan et al., 2014 ). Both whey and beef are high-quality protein sources with a very similar amino acid composition
Fernando Naclerio, Eneko Larumbe-Zabala, Mar Larrosa, Aitor Centeno, Jonathan Esteve-Lanao and Diego Moreno-Pérez
Samuel G. Impey, Kelly M. Hammond, Robert Naughton, Carl Langan-Evans, Sam O. Shepherd, Adam P. Sharples, Jessica Cegielski, Kenneth Smith, Stewart Jeromson, David L. Hamilton, Graeme L. Close and James P. Morton
al., 2009 ; Wilkinson et al., 2007 ). Contemporary guidelines recommend whey protein beverages due to their higher leucine content and rapid aminoacidemia upon ingestion ( Thomas et al., 2016 ), though hydrolyzed collagen beverages and gels are now commercially available and marketed to athletic
Paulo Sugihara Junior, Alex S. Ribeiro, Hellen C.G. Nabuco, Rodrigo R. Fernandes, Crisieli M. Tomeleri, Paolo M. Cunha, Danielle Venturini, Décio S. Barbosa, Brad J. Schoenfeld and Edilson S. Cyrino
that include untrained individuals therefore must be interpreted with a degree of circumspection when attempting to extrapolate results to a trained population. Whey protein (WP) contains the full complement of essential amino acids and is digested and absorbed rapidly ( Dangin et al., 2002 ; Phillips
Jordan D. Philpott, Chris Donnelly, Ian H. Walshe, Elizabeth E. MacKinley, James Dick, Stuart D.R. Galloway, Kevin D. Tipton and Oliver C. Witard
study was to investigate the impact of adding fish oil–derived n-3PUFA to a whey protein, leucine, and carbohydrate containing supplement over a six-week period on acute recovery from eccentric muscle damage in competitive soccer players. Rationale for combining n-3PUFA with whey protein, leucine, and
Thomas B. Walker, Jessica Smith, Monica Herrera, Breck Lebegue, Andrea Pinchak and Joseph Fischer
The purpose of this study was to investigate the ability of whey-protein and leucine supplementation to enhance physical and cognitive performance and body composition. Thirty moderately fit participants completed a modified Air Force fitness test, a computer-based cognition test, and a dual-energy X-ray-absorptiometry scan for body composition before and after supplementing their daily diet for 8 wk with either 19.7 g of whey protein and 6.2 g leucine (WPL) or a calorie-equivalent placebo (P). Bench-press performance increased significantly from Week 1 to Week 8 in the WPL group, whereas the increase in the P group was not significant. Push-up performance increased significantly for WPL, and P showed a nonsignificant increase. Total mass, fat-free mass, and lean body mass all increased significantly in the WPL group but showed no change in the P group. No differences were observed within or between groups for crunches, chin-ups, 3-mile-run time, or cognition. The authors conclude that supplementing with whey protein and leucine may provide an advantage to people whose performance benefits from increased upper body strength and/or lean body mass.
Darren G. Candow, Natalie C. Burke, T. Smith-Palmer and Darren G. Burke
The purpose was to compare changes in lean tissue mass, strength, and myof-brillar protein catabolism resulting from combining whey protein or soy protein with resistance training. Twenty-seven untrained healthy subjects (18 female, 9 male) age 18 to 35 y were randomly assigned (double blind) to supplement with whey protein (W; 1.2 g/kg body mass whey protein + 0.3 g/kg body mass sucrose power, N = 9: 6 female, 3 male), soy protein (S; 1.2 g/kg body mass soy protein + 0.3 g/kg body mass sucrose powder, N = 9: 6 female, 3 male) or placebo (P; 1.2 g/kg body mass maltodextrine + 0.3 g/kg body mass sucrose powder, N = 9: 6 female, 3 male) for 6 wk. Before and after training, measurements were taken for lean tissue mass (dual energy X-ray absorptiometry), strength (1-RM for bench press and hack squat), and an indicator of myofbrillar protein catabolism (urinary 3-methylhistidine). Results showed that protein supplementation during resistance training, independent of source, increased lean tissue mass and strength over isocaloric placebo and resistance training (P < 0.05). We conclude that young adults who supplement with protein during a structured resistance training program experience minimal beneficial effects in lean tissue mass and strength.
Mette Hansen, Jens Bangsbo, Jørgen Jensen, Bo Martin Bibby and Klavs Madsen
This trial aimed to examine the effect of whey protein hydrolysate intake before and after exercise sessions on endurance performance and recovery in elite orienteers during a training camp. Eighteen elite orienteers participated in a randomized controlled intervention trial during a 1-week training camp (13 exercise sessions). Half of the runners (PRO-CHO) ingested a protein drink before (0.3 g kg−1) and a protein-carbohydrate drink after (0.3 g protein kg−1 and 1 g carbohydrate kg−1) each exercise session. The others ingested energy and timematched carbohydrate drinks (CHO). A 4-km run-test with 20 control points was performed before and on the last day of the intervention. Blood and saliva were obtained in the mornings, before and after run-tests, and after the last training session. During the intervention, questionnaires were fulfilled regarding psychological sense of performance capacity and motivation. PRO-CHO and not CHO improved performance in the 4-km run-test (interaction p < .05). An increase in serum creatine kinase was observed during the week, which was greater in CHO than PRO-CHO (interactionp < .01). Lactate dehydrogenase (p < .001) and cortisol (p = .057) increased during the week, but the change did not differ between groups. Reduction in sense of performance capacity during the intervention was greater in CHO (p < .05) than PRO-CHO. In conclusion, ingestion of whey protein hydrolysate before and after each exercise session improves performance and reduces markers of muscle damage during a strenuous 1-week training camp. The results indicate that protein supplementation in conjunction with each exercise session facilitates the recovery from strenuous training in elite orienteers.
Scott C. Forbes, Linda McCargar, Paul Jelen and Gordon J. Bell
The purpose was to investigate the effects of a controlled typical 1-day diet supplemented with two different doses of whey protein isolate on blood amino acid profiles and hormonal concentrations following the final meal. Nine males (age: 29.6 ± 6.3 yrs) completed four conditions in random order: a control (C) condition of a typical mixed diet containing ~10% protein (0.8 g·kg–1), 65% carbohydrate, and 25% fat; a placebo (P) condition calorically matched with carbohydrate to the whey protein conditions; a low-dose condition of 0.8 grams of whey protein isolate per kilogram body mass per day (g·kg–1·d–1; W1) in addition to the typical mixed diet; or a high-dose condition of 1.6 g·kg–1·d–1 (W2) of supplemental whey protein in addition to the typical mixed diet. Following the final meal, significant (p < .05) increases in total amino acids, essential amino acids (EAA), branch-chained amino acids (BCAA), and leucine were observed in plasma with whey protein supplementation while no changes were observed in the control and placebo conditions. There was no significant group difference for glucose, insulin, testosterone, cortisol, or growth hormone. In conclusion, supplementing a typical daily food intake consisting of 0.8 g of protein·kg–1·d–1 with a whey protein isolate (an additional 0.8 or 1.6 g·kg–1·d–1) significantly elevated total amino acids, EAA, BCAA, and leucine but had no effect on glucose, insulin, testosterone, cortisol, or growth hormone following the final meal. Future acute and chronic supplementation research examining the physiological and health outcomes associated with elevated amino acid profiles is warranted.
Paul W. Macdermid and Stephen R. Stannard
This study compared a training diet recommended for endurance athletes (H-CHO) with an isoenergetic high protein (whey supplemented), moderate carbohydrate (H-Pro) diet on endurance cycling performance. Over two separate 7-d periods subjects (n = 7) ingested either H-CHO (7.9 ± 1.9 g · kg−1 · d−1 carbohydrate; 1.2 ± 0.3 g · kg−1 · d−1 fat; 1.3 ± 0.4 g · kg−1 · d−1 protein) or H-Pro (4.9 ± 1.8 g · kg−1 · d−1; 1.2 ± 0.3 g · kg−1 · d−1; 3.3 ± 0.4 g · kg−1 · d−1) diet in a randomized, balanced order. On day 8 subjects cycled (self-paced) for a body weight dependent (60 kJ/bm) amount of work. No differences occurred between energy intake (P = 0.422) or fat intake (P = 0.390) during the two dietary conditions. Performance was significantly (P = 0.010) impaired following H-Pro (153 ± 36) compared with H-CHO (127 ± 34 min). No differences between treatments were observed for physiological measures taken during the performance trials. These results indicate an ergolytic effect of a 7-d high protein diet on self-paced endurance cycling performance.
Paul J. Cribb, Andrew D. Williams, Michael F. Carey and Alan Hayes
Different dietary proteins affect whole body protein anabolism and accretion and therefore, have the potential to influence results obtained from resistance training. This study examined the effects of supplementation with two proteins, hydrolyzed whey isolate (WI) and casein (C), on strength, body composition, and plasma glutamine levels during a 10 wk, supervised resistance training program. In a double-blind protocol, 13 male, recreational bodybuilders supplemented their normal diet with either WI or C (1.5 gm/kg body wt/d) for the duration of the program. Strength was assessed by 1-RM in three exercises (barbell bench press, squat, and cable pull-down). Body composition was assessed by dual energy X-ray absorptiometry. Plasma glutamine levels were determined by the enzymatic method with spectrophotometric detection. All assessments occurred in the week before and the week following 10 wk of training. Plasma glutamine levels did not change in either supplement group following the intervention. The WI group achieved a significantly greater gain (P < 0.01) in lean mass than the C group (5.0 ± 0.3 vs. 0.8 ± 0.4 kg for WI and C, respectively) and a significant (P < 0.05) change in fat mass (−1.5 ± 0.5 kg) compared to the C group (+0.2 ± 0.3 kg). The WI group also achieved significantly greater (P < 0.05) improvements in strength compared to the C group in each assessment of strength. When the strength changes were expressed relative to body weight, the WI group still achieved significantly greater (P < 0.05) improvements in strength compared to the C group.