Comparison of plasma amino acid concentrations after whey protein hydrolysate intake in young men at rest and post-resistance exercise

Few studies have compared the differences between protein (whey protein hydrolysate (WPH) or whey protein concentrate (WPC)) intake conditions (at rest or post-resistance exercise). Therefore, the purpose of this study was to investigate the plasma amino acid levels after intake of WPH compared with WPC intake in young men at rest and post-resistance exercise. We also aimed to compare the differences in plasma amino acid levels after WPH intake with or without resistance exercise. Fifteen young men were recruited for this crossover study, where each participant took three supplements (placebo, WPH and WPC) once each at rest and post-resistance exercise over 9 weeks. Blood samples were collected at nine (0, 15, 30, 45, 60, 90, 120, 180, 240 min) and ten (pre, 0, 15, 30, 45, 60, 90, 120, 180, 240 min) time points, at rest and post-resistance exercise, respectively. Plasma amino acids (total amino acids, essential amino acids, branched amino acids and leucine) were measured. WPH intake resulted in faster bioavailability (approximately 15 min) and higher plasma amino acid concentrations in all plasma amino acids, regardless of the condition. In addition, WPH bioavailability tended to have similar peaks concentrations at rest and post-resistance exercise, whereas post-resistance exercise of WPC decreased sharply after 30 min and maintained a lower concentration than normal after 60 min. In conclusion, the results that WPH intake initially increased the concentration of plasma amino acids than WPC suggests that WPH is absorbed into the blood faster and may be more effective in increasing the rate of muscle protein synthesis. Moreover, although the intake of WPH after resistance exercise does not upregulate the peak concentrations of plasma amino acids, the synthesis of skeletal muscle can be increased through a rapid supply to tissues that require amino acids.

Protein intake; Whey protein hydrolysate; Resistance exercise; Plasma amino acid; Aminoacidemia

[1] Hooshmand-Moghadam B, Johne M, Golestani F, Lorenz K, Asad M, Maculewicz E, et al. Effects of soy milk ingestion immediately after resistance training on muscular-related biomarkers in older males: a randomized controlled trial. Biology of Sport. 2023; 40: 1207–1217.

[2] Lv X, Zhou C, Yan Q, Tan Z, Kang J, Tang S. Elucidating the underlying mechanism of amino acids to regulate muscle protein synthesis: impact on human health. Nutrition. 2022; 103–104: 111797.

[3] Atherton PJ, Etheridge T, Watt PW, Wilkinson D, Selby A, Rankin D, et al. Muscle full effect after oral protein: time-dependent concordance and discordance between human muscle protein synthesis and mTORC1 signaling. The American Journal of Clinical Nutrition. 2010; 92: 1080–1088.

[4] Bohé J, Low A, Wolfe RR, Rennie MJ. Human muscle protein synthesis is modulated by extracellular, not intramuscular amino acid availability: a dose-response study. The Journal of Physiology. 2003; 552: 315–324.

[5] Campbell WW, Deutz NEP, Volpi E, Apovian CM. Nutritional interventions: dietary protein needs and influences on skeletal muscle of older adults. The Journals of Gerontology: Series A. 2023; 78: 67–72.

[6] Kaspy MS, Hannaian SJ, Bell ZW, Churchward-Venne TA. The effects of branched-chain amino acids on muscle protein synthesis, muscle protein breakdown, and associated molecular signalling responses in humans: an update. Nutrition Research Reviews. 2023. [Preprint]

[7] Witard OC, Bannock L, Tipton KD. Making sense of muscle protein synthesis: a focus on muscle growth during resistance training. International Journal of Sport Nutrition and Exercise Metabolism. 2022; 32: 49–61.

[8] D’Hulst G, Masschelein E, De Bock K. Resistance exercise enhances long-term mTORC1 sensitivity to leucine. Molecular Metabolism. 2022; 66: 101615.

[9] Burd NA, West DW, Moore DR, Atherton PJ, Staples AW, Prior T, et al. Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men. The Journal of Nutrition. 2011; 141: 568–573.

[10] Khemtong C, Kuo CH, Chen CY, Jaime SJ, Condello G. Does branched-chain amino acids (BCAAs) supplementation attenuate muscle damage markers and soreness after resistance exercise in trained males? A meta-analysis of randomized controlled trials. Nutrients. 2021; 13: 1880.

[11] Cuyul-Vásquez I, Pezo-Navarrete J, Vargas-Arriagada C, Ortega-Díaz C, Sepúlveda-Loyola W, Hirabara SM, Marzuca-Nassr GN. Effectiveness of whey protein supplementation during resistance exercise training on skeletal muscle mass and strength in older people with sarcopenia: a systematic review and meta-analysis. Nutrients. 2023; 15: 3424.

[12] Pearson AG, Hind K, Macnaughton LS. The impact of dietary protein supplementation on recovery from resistance exercise-induced muscle damage: a systematic review with meta-analysis. European Journal of Clinical Nutrition. 2023; 77: 767–783.

[13] Wilkinson K, Koscien CP, Monteyne AJ, Wall BT, Stephens FB. Association of postprandial postexercise muscle protein synthesis rates with dietary leucine: a systematic review. Physiological Reports. 2023; 11: e15775.

[14] Master PBZ, Macedo RCO. Effects of dietary supplementation in sport and exercise: a review of evidence on milk proteins and amino acids. Critical Reviews in Food Science and Nutrition. 2021; 61: 1225–1239.

[15] Tang JE, Moore DR, Kujbida GW, Tarnopolsky MA, Phillips SM. Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. Journal of Applied Physiology. 2009; 107: 987–992.

[16] Pennings B, Boirie Y, Senden JM, Gijsen AP, Kuipers H, van Loon LJ. Whey protein stimulates postprandial muscle protein accretion more effectively than do casein and casein hydrolysate in older men. The American Journal of Clinical Nutrition. 2011; 93: 997–1005.

[17] Koopman R, Crombach N, Gijsen AP, Walrand S, Fauquant J, Kies AK, et al. Ingestion of a protein hydrolysate is accompanied by an accelerated in vivo digestion and absorption rate when compared with its intact protein. The American Journal of Clinical Nutrition. 2009; 90: 106–115.

[18] Sinha R, Radha C, Prakash J, Kaul P. Whey protein hydrolysate: functional properties, nutritional quality and utilization in beverage formulation. Food Chemistry. 2007; 101: 1484–1491.

[19] Tang T, Wu N, Tang S, Xiao N, Jiang Y, Tu Y, et al. Industrial application of protein hydrolysates in food. Journal of Agricultural and Food Chemistry. 2023; 71: 1788–1801.

[20] Moro T, Brightwell CR, Velarde B, Fry CS, Nakayama K, Sanbongi C, et al. Whey protein hydrolysate increases amino acid uptake, mTORC1 signaling, and protein synthesis in skeletal muscle of healthy young men in a randomized crossover trial. The Journal of Nutrition. 2019; 149: 1149–1158.

[21] Nakayama K, Sanbongi C, Ikegami S. Effects of whey protein hydrolysate ingestion on postprandial aminoacidemia compared with a free amino acid mixture in young men. Nutrients. 2018; 10: 507.

[22] Shen M, Zhang W, Wu G, Zhu L, Qi X, Zhang H. A systematic review and meta-analysis: effects of protein hydrolysate supplementation on fat-free mass and strength in resistance-trained individuals. Critical Reviews in Food Science and Nutrition. 2023; 63: 964–974.

[23] Kanda A, Nakayama K, Fukasawa T, Koga J, Kanegae M, Kawanaka K, et al. Post-exercise whey protein hydrolysate supplementation induces a greater increase in muscle protein synthesis than its constituent amino acid content. British Journal of Nutrition. 2013; 110: 981–987.

[24] Brzycki M. Strength testing—predicting a one-rep max from reps-to-fatigue. Journal of Physical Education, Recreation & Dance. 1993; 64: 88–90.

[25] Elovaris RA, Hutchison AT, Lange K, Horowitz M, Feinle-Bisset C, Luscombe-Marsh ND. Plasma free amino acid responses to whey protein and their relationships with gastric emptying, blood glucose-and appetite-regulatory hormones and energy intake in lean healthy men. Nutrients. 2019; 11: 2465.

[26] Morgan PT, Breen L. The role of protein hydrolysates for exercise-induced skeletal muscle recovery and adaptation: a current perspective. Nutrition & Metabolism. 2021; 18: 44.

[27] Nakayama K, Tagawa R, Saito Y, Sanbongi C. Effects of whey protein hydrolysate ingestion on post-exercise muscle protein synthesis compared with intact whey protein in rats. Nutrition & Metabolism. 2019; 16: 90.

[28] Joanisse S, McKendry J, Lim C, Nunes EA, Stokes T, Mcleod JC, et al. Understanding the effects of nutrition and post-exercise nutrition on skeletal muscle protein turnover: insights from stable isotope studies. Clinical Nutrition Open Science. 2021; 36: 56–77.

[29] Moore DR. Maximizing post-exercise anabolism: the case for relative protein intakes. Frontiers in Nutrition. 2019; 6: 147.

[30] Zaromskyte G, Prokopidis K, Ioannidis T, Tipton KD, Witard OC. Evaluating the leucine trigger hypothesis to explain the post-prandial regulation of muscle protein synthesis in young and older adults: a systematic review. Frontiers in Nutrition. 2021; 8: 685165.

[31] Marshall RN, Morgan PT, Smeuninx B, Quinlan JI, Brook MS, Atherton PJ, et al. Myofibrillar protein synthesis and acute intracellular signaling with elastic band resistance exercise in young and older men. Medicine & Science in Sports & Exercise. 2023; 55: 398–408.

[32] Yang Y, Breen L, Burd NA, Hector AJ, Churchward-Venne TA, Josse AR, et al. Resistance exercise enhances myofibrillar protein synthesis with graded intakes of whey protein in older men. British Journal of Nutrition. 2012; 108: 1780–1788.

[33] Moore DR, Robinson MJ, Fry JL, Tang JE, Glover EI, Wilkinson SB, et al. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. The American Journal of Clinical Nutrition. 2009; 89: 161–168.

[34] Hulmi JJ, Lockwood CM, Stout JR. Effect of protein/essential amino acids and resistance training on skeletal muscle hypertrophy: a case for whey protein. Nutrition & Metabolism. 2010; 7: 51.