5151
05-05-2009, 01:17 AM
I posted this on another "bigger" board but thought some of you guys that don't travel there might be interested in it:
With hydrolyzed milk proteins being the popular supplement of late and appearing in more products I figured the research must be looking more and more promising and not a bunch of companies playing follow the leader. After going through the descriptions of some of the products available I saw their benefits are based around two general claims:
1. Hydrolyzed protein is pre-digested and therefore enters the blood stream more quickly than whey.
2. There exists a correlation between the speed of amino acids appearing in the blood stream and the rate of muscle growth.
So being the pubmed ninja I am I decided to look at the legitimacy of these claims. Hopefully this can spur some discussion.
Claim 1
As far as I can tell the notion that the amino acids from hydrolyzed whey protein reach the blood stream faster and in higher concentrations than those from intact whey protein stems from a study published in 1991 by Moughan et al (1). This study was performed on piglets and showed quicker gastric emptying and intestinal absorption of amino acids of bovine-milk hydrolysate versus intact bovine-milk. Obviously this has little application to humans because it was done on piglets and the confounding variable of intact milk protein being used rather than just whey.
Fast forward to 2004 when Calbet and Holst publish a study comparing the gastric emptying times and increase in plasma amino acid concentrations of whey and casein compared to their hydrolysate counterparts (2). The strengths of this study include the use of humans and the inclusion of the extent of hydrolysis (94% of the whey was in the form of oligopeptide with an average chain length of 3.7, 93% of the casein was in the form of oligopeptide with an average chain length of 3.8). This is important because at least two products available on the market highlight their chain length as a benefit: one boasts an average chain length of 4 and the other boasts di- and tri- peptides. The results of the study showed no significant differences between whey protein and the two hydrolysates in the rate of plasma increases in BCAA, EAA and TAA(total amino acids). All four solutions had similar gastric emptying times.
A more recent study showed similar results of hydrolysis not affecting the estimated rate of gastric emptying when compared to whey isolate (3). The whey hydrolysate used in that particular study was Optipep80 with a 30% degree of hydrolysis and did not specify the di- and tri- peptide amount or average chain length. Interestingly there was no difference in the rate of BCAAs appearing in the plasma in the first 40 minutes and the whey isolate outperformed the whey hydrolysate in BCAA mean peak concentration, area under the curve and maximum plasma concentration. The only other amino acid observed was phenylalanine and a significant difference was seen between the 30 and 60 minute mark though within the fist 15 minutes no difference was seen.
The claim of hydrolyzed protein entering the blood stream faster than whey protein is without basis.
Claim 2
This claim seems to be based on a study by Cribb et al. that compared hydrolyzed whey isolate to casein?s impact on body composition(among other things but for the scope of this post I just planned on discussing body composition) (4). The study used recreational bodybuilders that consumed 1.5g/kg of either hydrolyzed whey or casein during a 12-week Max-OT resistance training program in addition to their habitual daily diet. The results were a statistically significant increase in lean body mass and decrease in fat mass in the hydrolyzed whey group compared to the casein group.
This obviously means chronic supplementation of whey hydrolysate will result in more muscle and less fat correct? One issue is that the previous section showed there was no difference in speed of amino acids appearing in the blood stream compared to intact whey protein therefore it can be speculated a much cheaper intact whey protein could have been substituted with similar results. This speculation is supported by a study done by Dangin et al. where a single meal of casein was compared to several small feedings of whey to mimic slow digestion (5). Despite equal grams of protein the whey outperformed the casein in postprandial leucine balance indicating it was the amino acid component or some other property inherent to whey that provided the benefit and not speed of digestion as a single meal of whey compared to casein has been shown to be inferior for postprandial leucine balance (5,6).
This sort of leads to a discussion of whether fast or slow proteins are superior for muscle growth in general and that?s not what I wanted to discuss with this post but rather I just wanted to keep it specific the WPH.
If I've missed the point completely or am grossly ignorant of some huge body of research just let me know.
References
1. http://www.ncbi.nlm.nih.gov/pubmed/2051276?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum
2. http://www.springerlink.com/content/j812c0cabk3t2dm0/
3. http://www.ncbi.nlm.nih.gov/pubmed/18679613
4. http://www.ncbi.nlm.nih.gov/pubmed/17240782
5. http://ajpendo.physiology.org/cgi/content/abstract/280/2/E340
6. http://www.pnas.org/content/94/26/14930.full?ck=nck
7. http://jn.nutrition.org/cgi/content/full/132/10/3228S
With hydrolyzed milk proteins being the popular supplement of late and appearing in more products I figured the research must be looking more and more promising and not a bunch of companies playing follow the leader. After going through the descriptions of some of the products available I saw their benefits are based around two general claims:
1. Hydrolyzed protein is pre-digested and therefore enters the blood stream more quickly than whey.
2. There exists a correlation between the speed of amino acids appearing in the blood stream and the rate of muscle growth.
So being the pubmed ninja I am I decided to look at the legitimacy of these claims. Hopefully this can spur some discussion.
Claim 1
As far as I can tell the notion that the amino acids from hydrolyzed whey protein reach the blood stream faster and in higher concentrations than those from intact whey protein stems from a study published in 1991 by Moughan et al (1). This study was performed on piglets and showed quicker gastric emptying and intestinal absorption of amino acids of bovine-milk hydrolysate versus intact bovine-milk. Obviously this has little application to humans because it was done on piglets and the confounding variable of intact milk protein being used rather than just whey.
Fast forward to 2004 when Calbet and Holst publish a study comparing the gastric emptying times and increase in plasma amino acid concentrations of whey and casein compared to their hydrolysate counterparts (2). The strengths of this study include the use of humans and the inclusion of the extent of hydrolysis (94% of the whey was in the form of oligopeptide with an average chain length of 3.7, 93% of the casein was in the form of oligopeptide with an average chain length of 3.8). This is important because at least two products available on the market highlight their chain length as a benefit: one boasts an average chain length of 4 and the other boasts di- and tri- peptides. The results of the study showed no significant differences between whey protein and the two hydrolysates in the rate of plasma increases in BCAA, EAA and TAA(total amino acids). All four solutions had similar gastric emptying times.
A more recent study showed similar results of hydrolysis not affecting the estimated rate of gastric emptying when compared to whey isolate (3). The whey hydrolysate used in that particular study was Optipep80 with a 30% degree of hydrolysis and did not specify the di- and tri- peptide amount or average chain length. Interestingly there was no difference in the rate of BCAAs appearing in the plasma in the first 40 minutes and the whey isolate outperformed the whey hydrolysate in BCAA mean peak concentration, area under the curve and maximum plasma concentration. The only other amino acid observed was phenylalanine and a significant difference was seen between the 30 and 60 minute mark though within the fist 15 minutes no difference was seen.
The claim of hydrolyzed protein entering the blood stream faster than whey protein is without basis.
Claim 2
This claim seems to be based on a study by Cribb et al. that compared hydrolyzed whey isolate to casein?s impact on body composition(among other things but for the scope of this post I just planned on discussing body composition) (4). The study used recreational bodybuilders that consumed 1.5g/kg of either hydrolyzed whey or casein during a 12-week Max-OT resistance training program in addition to their habitual daily diet. The results were a statistically significant increase in lean body mass and decrease in fat mass in the hydrolyzed whey group compared to the casein group.
This obviously means chronic supplementation of whey hydrolysate will result in more muscle and less fat correct? One issue is that the previous section showed there was no difference in speed of amino acids appearing in the blood stream compared to intact whey protein therefore it can be speculated a much cheaper intact whey protein could have been substituted with similar results. This speculation is supported by a study done by Dangin et al. where a single meal of casein was compared to several small feedings of whey to mimic slow digestion (5). Despite equal grams of protein the whey outperformed the casein in postprandial leucine balance indicating it was the amino acid component or some other property inherent to whey that provided the benefit and not speed of digestion as a single meal of whey compared to casein has been shown to be inferior for postprandial leucine balance (5,6).
This sort of leads to a discussion of whether fast or slow proteins are superior for muscle growth in general and that?s not what I wanted to discuss with this post but rather I just wanted to keep it specific the WPH.
If I've missed the point completely or am grossly ignorant of some huge body of research just let me know.
References
1. http://www.ncbi.nlm.nih.gov/pubmed/2051276?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum
2. http://www.springerlink.com/content/j812c0cabk3t2dm0/
3. http://www.ncbi.nlm.nih.gov/pubmed/18679613
4. http://www.ncbi.nlm.nih.gov/pubmed/17240782
5. http://ajpendo.physiology.org/cgi/content/abstract/280/2/E340
6. http://www.pnas.org/content/94/26/14930.full?ck=nck
7. http://jn.nutrition.org/cgi/content/full/132/10/3228S