PROGENEX Recovery Research
The Science of PROGENEX Recovery
Scientific Review of Whey Protein Hydrolysates and Sports Performance
Sports performance is associated with several physiological challenges: dehydration, depletion of muscle fuels, increased oxidant formation, mechanical damage to muscle, oxidation of essential amino acids leading to immune suppression and low recovery from exercise. Therefore, many athletes look for an edge to enhance performance, endurance, stamina, muscle strength and/or decrease recovery time. Some individuals use improved training, better nutrition, individual sports nutrition supplements or combination of specific nutrients before, after or during training to target desired outcomes based on scientific studies in the literature. PROGENEX, a science-based complete sporst nutritional company, has formulatedPROGENEX Recovery 100% whey protein supplement using a whey protein hydrolysate, with a very high percentage of di- and tripeptides, to improve recovery time and speed tissue repair from eccentric exercise-induced muscle damage.
Basic Facts about Protein Hydrolysates
Not all protein hydrolysates are created equal. While all protein hydrolysates are produced from purified protein sources by heating with acid or preferably addition of proteolytic enzymes followed by a purification process (1), each protein hydrolysate is a complex mixture of peptides of different chain lengths along with free amino acids. Two protein hydrolysates made by different methods may have a similar degree of hydrolysis but their absorption kinetics based on their proportion of di- and tripeptides are likely quite different.
Absorption of Protein Hydrolysates
Research in 1994 established that only di- and tripeptides are absorbed intact after luminal and brush-border peptidase digestion (2). Longer chain peptides undergo hydrolysis at the brush-border before they can be absorbed. More importantly, the proportion of di- and tripeptides determines the absorption kinetics of a protein hydrolysate (3). Adi-bi and Morse (4) established that tetraglycine undergoes hydrolysis by brush border oligopeptidases in the human jejunum; the hydrolysis of tetraglycine to either di- or tripeptides is the rate limiting step in the uptake of glycine; greater glycine uptake occurs from di- and triglycine than from freeglycine. Protein hydrolysates containing a preponderance of di- and tripeptides, such as whey protein hydrolysate, are absorbed faster than intact proteins and free amino acids. Under conditions of rapid intestinal infusion, amino acids from protein hydrolysates appear in the portal circulation faster than even free amino acids (5)
Utilization of Whey Protein Hydrolysates
Fast-acting protein hydrolysates and/or amino acids supplements result in less efficient uptake by the splanchnic bed—liver and portal-drained viscera (stomach, intestines, pancreas and spleen)—increasing the magnitude of amino acids in the systemic circulation that are available for muscle growth and repair (muscle protein anabolism) (1). First pass extraction by splanchnic tissues describes the proportion of ingested amino acids that is sequestered during its initial transit through the splanchnic bed and not appearing in systemic blood (6). The portal-drained visceracan account for between 20 to 35 % of whole body protein turnover and energy expenditure (6). Therefore, the kinetics of amino acid absorption can substantially modulate their ability to stimulate muscle protein anabolism. An oral supplement containing 30g of carbohydrate and 15g of essential amino acids induces a substantially greater anabolic effect than ingestion of a mixed meal containing a similar amount of essential amino acids (7). Ingestion of whey protein hydrolysate results in a larger increase in blood amino acids and mixed muscle protein synthesis than soy protein or casein both at rest and after resistance exercise (8).
Whey Hydrolysates, Body Composition, Muscular Strength, Performance and Recovery
During training: Recreational male bodybuilders supplemented their normal diet with either whey protein hydrolysate or casein (1.5g/kg body weight/day) during a10 week supervised resistance training program (9). The group supplemented with whey hydrolysate achieved substantially greater gains in muscle strength and lean body mass compared to the casein group (9).Post training: To determine whether hydrolyzed whey protein speeds recovery following isometric exercise, males performed 100 maximal eccentric contractions of their knee extensors and then consumed either 24g of hydrolyzed whey protein or intact whey protein. Peak isometric torque recovered fully in 6 hours for individuals given the whey protein hydrolysate whereas it remained suppressed in the group given intact whey protein (10). Therefore, whey protein hydrolysates offer ergogenic benefits when consumed during and after exercise.
Comparison of Glucose Verses Glucose and Whey/Casein Hydrolysates or Branched Chain Amino Acids on Muscle Glycogen Resynthesis. (Animal Studies)
Fully restored muscle glycogen levels are critical to recovery and future training. If muscle glycogen stores are not fully recovered, the time to exhaustion diminishes resulting in reduced training ability.
Knowing what specific nutrients can boost muscle glycogen stores can improve an athlete’s performance. Morifuji et al (11) fed male Sprague-Dawley rats either glucose alone, glucose + whey protein, glucose + whey protein hydrolysate, glucose + casein hydrolysate or glucose + branched chain amino acids immediately after a glycogen-depleting exercise. Only the rats given the glucose + whey protein hydrolysate had significant increases in skeletal muscle glycogen levels compared to the other protein sources or BCAA. Using rat L6 myotubes, Morifuji et al (12) showed that branched chain amino acid-containing di-peptides in whey protein hydrolysate (Ile-Leu, Leu-Val, Val-Leu, Ile-Ile, Leu-Ile, Ile, Leu) significantly stimulated glucose uptake using an in vitro model. These researchers also demonstrated that the main di-peptide in whey protein hydrolysate (Ile-Leu) stimulated glucose uptake in rat isolated epitrochlearis muscles. Therefore, whey protein hydrolysate enhances the effects of carbohydrate ingestion on post-exercise muscle glycogen resynthesis for both in vivo and in vitro models.
Insulin Secretion and Skeletal Muscle Anabolism
The most important trigger for insulin secretion is glucose. However, secretion of insulin can be induced by amino acids as well. Leucine is a potent insulin tropic molecule, but recent evidence suggests that a rise in glucose concentration is necessary for leucine to stimulate significant insulin secretion (13).Additional research has shown that insulin-induced increase in muscle protein anabolism is age dependent. In young adults, insulin is mainly permissive rather than stimulatory for muscle protein anabolism, whereas in older adults super high levels of insulin appear to be necessary to stimulate muscle protein anabolism (14).
1. Manninen, AH. Protein hydrolysates in sports nutrition. Nutr & Metab 2009, 6:38-43.
2. Grimble GK. The significance of peptides in clinical nutrition. Annul Rev Nutr 1994, 14:419-447.
3. Grimble GK, Guilera SM, Sesay HF. The influence of whey hydrolysate peptide chain length on nitrogen and carbohydrate absorption in the perfused human jejunum. Clin Nutr 1994, 13:46.
4. Adi-bi SA, Morse EL. The number of glycine residues, which limits intact absorption of glycine oligopeptides in human jejunum. J Clin Invest 1997, 60:1008-1016.
5. Monchi M, Rerat AA. Comparison of net protein utilization of milk protein milk enzymatic hydrolysates and free amino acid mixture with a close pattern in the rat. J Parenter Enteral Nutr 1993, 17:355-363.
6. Stoll B, Burrin DG. Measuring splanchinic amino acid metabolism in vivo using stable isotope tracers. J. Anim Sci 2006, 84 (Suppl) E:60-72.
7. Paddon-Jones D, Sheffield-Moore M, Arasland A, Wolfe RR, Ferrando AA. Exogenous amino acids stimulate human muscle anabolism without interfering with the response to mixed meal ingestion. Am J Physiol Endocrinol Metab 2005, 288:E761-767.
8. Tang JE, Moore DR, Kuijbida 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. J Appl Physiol 2009, 107:987-992.
9. Cribb PJ, Williams CD, Carey MF, Hayes A. The effect of whey isolate and resistance training on strength, body composition and plasma glutamine. Int JSport Nutr Exerc Metab 2006, 16:494-509.
10. Buckley JD, Thompson RL, Coates AM, Howe PR, DeNichilo MO, Rowney MK. Supplementation with a whey protein hydrolysate enhances recovery of muscle force-generating capacity following eccentric exercise. J Sci Med Sport 2010, 13:178-181.
11. Morifuji M, Kanda A, Koga J, Kawanaka K, Higuchi M. Post exercise carbohydrate plus whey protein hydrolysates supplementation increases skeletal muscle glycogen level in rats. Amino Acids 2010, 38: 1109-1015.
12. Morifuji M, Koga J, Kawanaka K, Higuchi M. Branched-chain amino acid-containing di-peptides, identified from whey protein hydrolysates, stimulate glucose uptake rate of L6 myotubes and isolated skeletal muscles. J Nutr Sci Vitaminol (Tokyo) 2009, 55: 81-86.