Minimal whey protein with carbohydrate stimulates muscle protein synthesis following resistance exercise in trained young men

Abstract

Whey protein is a supplemental protein source often used by athletes, particularly those aiming to gain muscle mass; however, direct evidence for its efficacy in stimulating muscle protein synthesis (MPS) is lacking. We aimed to determine the impact of consuming whey protein on skeletal muscle protein turnover in the post-exercise period. Eight healthy resistance-trained young men (age=21+/-1 .0 years; BMI=26.8+/-0.9 kg/m2 (means+/-SE)) participated in a double-blind randomized crossover trial in which they performed a unilateral leg resistance exercise workout (EX: 4 sets of knee extensions and 4 sets of leg press; 8-10 repetitions/set; 80% of maximal), such that one leg was not exercised and acted as a rested (RE) comparator. After exercise, subjects consumed either an isoenergetic whey protein plus carbohydrate beverage (WHEY: 10 g protein and 21 g fructose) or a carbohydrate-only beverage (CHO: 21 g fructose and 10 g maltodextran). Subjects received pulse-tracer injections of L-[ring-2H5]phenylalanine and L-[15N]phenylalanine to measure MPS. Exercise stimulated a rise in MPS in the WHEY-EX and CHO-EX legs, which were greater than MPS in the WHEY-RE leg and the CHO-RE leg (all p<0.05), respectively. The rate of MPS in the WHEY-EX leg was greater than in the CHO-EX leg (p<0.001). We conclude that a small dose (10 g) of whey protein with carbohydrate (21 g) can stimulate a rise in MPS after resistance exercise in trained young men that would be supportive of a positive net protein balance, which, over time, would lead to hypertrophy.

Effects of Whey Protein Alone or as Part of a Multi-ingredient Formulation on Strength, Fat-Free Mass, or Lean Body Mass in Resistance-Trained Individuals: A Meta-analysis

“…In comparison to other protein sources, whey protein has greater bioavailability and solubility along with a higher concentration of branched-chain amino acid (BCAA), specifically leucine [2,1,3]. Findings from two previous meta-analyses of randomized controlled trials (RCTs) support the positive effect of high quality protein supplementation, including whey, to maximize the increase in muscle mass [4,5] and strength [4] when combined with prolonged (≥4 weeks) resistance training interventions.…”

“…In summary, although several studies have analyzed the effect of whey protein supplementation on resistance training performance and outcomes [6][7][8][9], only some of them have specifically focused on resistance training individuals [10,11,3,12]. Indeed, only a few studies were focused on recreationally or well strength-trained athletes, and have reported a positive effect of whey, administered alone or combined with other nutrients, to maximize strength [13,2], lean body mass (LBM) or fat free mass (FFM) gains [2,14].…”

“…Methodological differences related to the study design and type of intervention, including supplementation strategies, would have been the cause of some controversies and inconsistencies regarding the most effective doses and methods of consumption for maximizing strength gains and muscle mass accretion in regular resistance-training athletes. In addition, the administration of different supplements containing only whey protein [3] or multi-ingredient formulas, where whey proteins are administered together with carbohydrates [15], other protein sources such as casein [16], bovine colostrum [17], or enriched with amino acid [16], creatine, β-hydroxy β-methylbutyrate (HMB) or L-carnitine [13,18], have impeded a better understanding of the real effect of whey protein supplementation to support strength and muscle mass gains in resistance trained individuals.…”

Effectiveness of Whey Protein Supplement in Resistance Trained Individuals

“…Whey protein extract, because of its increased bioavailability and solubility, and its higher percentage content of EAA including BCAAs, specifically Leucine, has been proposed as the best optimal form of protein for strength and power athletes [17,45,51]. Although several studies have analysed the effect of whey protein supplementation on resistance training performance and outcomes only some of them have focused on resistance trained individuals [12,17,23,24,26,38,52,53].…”

“…Although some studies have shown greater strength, muscular hypertrophy and/or Lean Body Mass (LBM) gains when resistance training is combined with whey protein alone or in conjunction with carbohydrates other protein sources enriched with amino acids or creatine; there are still some inconsistencies regarding the most appropriate effective doses and ingestion-timing strategy for optimizing resistance training induced adaptations and outcomes (strength gain or muscle mass accretion) [17][18][19][20][21].…”