Protein is Protein
Protein is by all standards one of the most, if not THE most important nutrient related to bodybuilding and muscular adaptations. The body will conserve protein over fat and carbohydrates during times of stress; that is how important it is. BUT, not all proteins were created equal. Meat proteins are a higher quality protein than most plant proteins as they are a more complete source and have a higher biological value – that is the proteins in the meats are better incorporated into the tissues of the body. Whey protein is also different from casein protein even though they are both derived from milk. Whey protein is digested faster than casein protein and provides more amino acids in the blood however for a shorter period of time. Let’s have a closer look at one of the most common sources of protein taken by people worldwide.
Whey protein is a protein derived as a by-product of cheese production. It is less allergenic than casein protein. Most of the fat is removed during the production process, however some is still left. Extremely common within the supplement universe, it is widely available in three forms:
- Concentrate – contains less fat and cholesterol, and also contains a higher amount of carbohydrates in the form of lactose.
- Isolate – processed to remove fat, cholesterol and lactose – contains a higher percentage of protein than whey protein concentrate.
- Hydrolysed – processed so that the proteins are smaller.
Recently hydrolysed protein has received a lot of attention, but is all this attention warranted?
Hydrolysed Protein - The Next Best Thing?
As previously mentioned, hydrolysed whey protein is protein that has been hydrolysed. Whole proteins are quite large molecules which the body can’t use, except for very special circumstances. In order to be utilised, these whole proteins must be chopped up into smaller molecules through a process called hydrolysis. To be able to be absorbed by the body, protein must be either in the form of di- or tri- peptides or free amino acids. Hydrolysation does the body’s work for you and breaks whole proteins into smaller peptides including di- and tri- peptides. Theoretically this should mean hydrolysed whey protein is absorbed faster by the body than whole intact proteins and give you faster access to the protein you need to build up that muscle. This is in fact the case as shown by Koopman et al (2009)1 as well as some other studies2,3. Muscle protein synthesis rates were also increased with use of hydrolysates over whole proteins in the Koopman study. By being faster absorbed than whole intact proteins, use of hydrolysed whey protein makes the most of the window of opportunity pre and post workout in supplying the muscles with the amino acids it needs to muscle adaptations4.
Hydrolysed Protein vs. Free Amino Acids
Since the body can absorb protein as di- and tri- peptides as well as free amino acids, would it be fine to just use free amino acids? On a physiological basis, studies have shown that in fact di- and tri- peptides are absorbed more easily and at a higher rate than free amino acids2,5. This is because di- and tri- peptide hydrolysates go through a different carrier system to enter the bloodstream. The presence of large volumes of free amino acids causes competition between the free amino acid carriers to bring them across the gut into the bloodstream, causing a delay in the delivery of amino acids to structures of the body including muscles. The absorption of free amino acids is also controlled by the level of sodium in the body as well as the acidity of the intestinal environment. These issues do not apply for the absorption of di- and tri- peptides. Other studies have shown greater retention of protein in the body with use of peptides rather than free amino acids.6
Hydrolysed Protein - What Else Can It Do?
So summarising the first couple of points; hydrolysed whey is able to be absorbed faster than whole intact proteins and free amino acids. What this means is that your body will be able to utilise these proteins faster as they will be available faster. Hydrolysed peptides are also capable of improving nitrogen retention over whole intact proteins7 and free amino acids8. Better nitrogen retention means continual positive nitrogen balance – a crucial factor for promoting an anabolic environment in the body. While the studies displaying these qualities of hydrolysed protein were animal studies, it is important to understand that the method of transport for peptides and proteins is the same. But to appease the critics, let’s examine some effects of hydrolysed protein on humans. Buckley et al (2010)9 showed that consuming hydrolysed whey protein led to improved recovery from fatiguing eccentric exercise than non-hydrolysed whey protein isolate. Two other studies performed by van Loon et al (2000)10,11 were able to show that hydrolysed protein with carbohydrates were able to raise the level of insulin in an individual almost 100% more than with carbohydrates alone.12 Insulin as you may or may not know is an amazing anabolic hormone and crucial during exercise and during recovery to drive glycogen storage in muscles. Other studies have also shown hydrolysed proteins are effective in promoting skeletal muscle gains1, improving muscle strength gains13 and stimulating muscle protein synthesis during exercise.14 Furthermore, hydrolysates may be beneficial for infants as well. Infants who were fed exclusively hydrolysed protein over cow’s milk formulas had normal weight gains. Increased weight gain early in life puts you at increased risk of other conditions such as obesity and diabetes later in life. The best option is always going to be breast milk, but if this is not an option, a hydrolysed protein formula may prove to be better and less allergenic.
Protein Quality For Bodybuilders
So far, the rap for hydrolysed whey protein is rather good. So how do you go about selecting the right hydrolysed protein for you? The degree of hydrolysation is an important factor to consider. The fact is, hydrolysation simply creates smaller proteins. This could mean di-, tri- or larger peptides. A good hydrolysed whey should have a large proportion of its content as di- and tri- peptides as these are the proteins which will be more easily absorbed into your system. Many supplement companies will also use fillers as a way to bulk up their content and thus the percentage of di- and tri- peptides to other ingredients may be reduced. The method of hydrolysation is also an important factor to consider. Hydrolysation of proteins can be done either with a strong acid or base or using enzymes. A protein hydrolysed by enzymes is better in preserving the amino acid profile of the product as acid hydrolysed products usually oxidise important amino acids lowering protein quality and biological value.15 Unfortunately from experience, many companies do not contain this information in their packaging so it might benefit you to call up the company to check these factors before investing in a hydrolysed protein supplement for yourself.
Hydrolysed Protein - The Final Word
While hydrolysed protein is absorbed faster than free amino acids and whole intact proteins, this quality’s effect on muscle protein synthesis and adaptation as well as in exercise and sports performance is still inconclusive and more studies need to be done. The fact is, protein is digested and absorbed within 45 mins to an hour, which is within the window of opportunity of protein’s ability to cause positive muscular adaptations including muscle growth after exercise. Protein supplements themselves as either intact or free amino acids are absorbed quite rapidly anyway. Whether or not this time advantage has any extra benefits over the long term in groups of healthy people is still undecided. Many studies suggesting benefits of hydrolysed protein are also focusing on protein in general rather than comparing hydrolysed over non-hydrolysed proteins. Further research into comparisons of hydrolysed over non hydrolysed proteins and different types of hydrolysed proteins; whey vs. casein will help provide a better picture. For now though, in this author’s opinion, hydrolysed protein into di- and tri-peptides may be a useful addition over regular protein powders or isolate proteins and may be beneficially stacked with other supplements to help you get the most out of your training.
1 Koopman R, Crombach N, Gijsen AP, Walrand S, Fauquant J, Kies AK, Lemosquet S, Saris WH, Boirie Y, van Loon LJ. ‘Ingestion of a protein hydrolysate is accompanied by an accelerated in vivo digestion and absorption rate when compared with its intact protein.’ Am J Clin Nutr. 2009 Jul;90(1):106-15. Epub 2009 May 27.
2 Di Pasquale, M.G. ‘Amino acids and proteins for the athlete: The anabolic edge.’ (1997) Boca Raton, FL:
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4 Tipton KD, Rasmussen BB, Miller SL, et al. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise.Am J Physiol Endocrinol Metab. Aug 2001;281(2):E197 – 206.
5 Adibi SA. ‘Intestinal phase of protein assimilation in man.’ Am J Clin Nutr. 1976 Feb;29(2):205-15.
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7 Boza JJ, Martínez-Augustin O, Baró L, Suarez MD, Gil A. ‘Protein v. enzymic protein hydrolysates. Nitrogen utilization in starved rats.’ Br J Nutr. 1995 Jan;73(1):65-71.
8 Yamamoto S, Korin T, Anzai M, Wang MF, Hosoi A, Abe A, Kishi K, Inoue G. ‘Comparative effects of protein, protein hydrolysate and amino acid diets on nitrogen metabolism of normal, protein-deficient, gastrectomized or hepatectomized rats.’ J Nutr. 1985 Nov;115(11):1436-46.
9 Buckley JD, Thomson 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 Jan;13(1):178-81. Epub 2008 Sep 2.
10 van Loon LJ, Saris WH, Verhagen H, Wagenmakers AJ. ‘Plasma insulin responses after ingestion of different amino acid or protein mixtures with carbohydrate.’ Am J Clin Nutr. 2000 Jul;72(1):96-105.
11 van Loon LJ, Kruijshoop M, Verhagen H, Saris WH, Wagenmakers AJ. ‘Ingestion of protein hydrolysate and amino acid-carbohydrate mixtures increases postexercise plasma insulin responses in men.’ J Nutr. Oct 2000;130(10):2508 – 2513.
12 Manninen, AH. ‘Protein hydrolysates in sports and exercise: A brief review.’ Journ. Of Sports Sci. And Med. (2004) 3, 60-63
13 Cribb PJ, Williams AD, Carey MF, Hayes A. ‘The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine.’ Int J Sport Nutr Exerc Metab. 2006 Oct;16(5):494-509.
14 Beelen M, Koopman R, Gijsen AP, Vandereyt H, Kies AK, Kuipers H, Saris WH, van Loon LJ. ‘Protein coingestion stimulates muscle protein synthesis during resistance-type exercise.’ Am J Physiol Endocrinol Metab. 2008 Jul;295(1):E70-7. Epub 2008 Apr 22.
15 Bucci, L.R. and Unlu, L. ‘Protein and amino acid supplements in exercise and sport. In: Energy yielding macronutrients and energy metabolism in sports nutrition.’ (2000) Eds: Wolinsky, I., Driskell, J.A.
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