Bodybuilding Forum

talisa1551 · Joined: 30 Oct 2006 Posts: 17 Location: china

"I found it very interesting to look over comparisons of casein versus Whey protein and the effects on protein absorbtion, breakdown (catabolism), and synthesis (anabolism).

Boirie et al.(2) found that a 30 gram feeding of casein protein versus whey protein had different effects on post-prandial (Prandial: Of or relating to a meal) protein gain. Both whey and casein are proteins derived from milk. In essence, they showed that whey protein is absorbed very quickly producing peak levels of amino acids at approximately 60-90 minutes after ingestion and then returning to baseline levels at approximately 3-4 hours post-ingestion. Casein on the other produced a much slower and less dramatic rise in amino acid levels peaking at approximately 60-90 minutes but maintaining higher levels of amino acids (versus baseline) over the entire 7-hr time frame.

Evidently, the differences in digestion and absorption translate into differences in protein metabolism. For instance, they discovered that whole body protein breakdown was inhibited by 34% by casein ingestion but not by whey. However, whey protein ingestion stimulated protein synthesis by 68% while casein stimulated protein synthesis to a lesser extent (+31%). However, when they looked at the ‘net leucine balance’ over the 7-hour time period after ingestion, casein ingestion resulted in a significantly higher net balance (i.e., post-feeding protein deposition was greater). Apparently, a fast absorbing protein such as whey stimulates protein synthesis tremendously but a large part of the protein is also oxidized (used as fuel). Thus, one might conclude from this single study that a single feeding of a ‘slow’ protein such as casein is superior for promoting protein accretion to a ‘fast’ protein such as whey when examined in healthy subjects over a 7-hr time frame.

However, this same laboratory followed this study with a more in-depth investigation.(3) They took four groups of 5 or 6 young men and had them consume a 30-gram protein meal. However, they were divided into four categories:
a) a single meal of slowly digested casein (CAS)
b) a single meal of free form amino acids that had the same composition as the casein (AA)
c) a single meal of rapidly digested whey protein (WP)
d) repeated small meals of whey protein mimicking the slow digestion rate seen in the casein (RPT-WP). The RPT-WP group had 13 small whey protein meals given every 20 minutes over four hours. All subjects were examined over a 7-hr period.

When they examined leucine balance (a measure of whole body anabolism), CAS was found to be superior to AA and the RPT-WP was superior to WP. And with regards to RPT-WP versus CAS, their preliminary data suggest that RPT-WP is better than CAS.

Clearly, these two studies show that the digestion rate of protein may be more important than other factors such as amino acid composition. Moreover, the amino acid composition of whey and casein are strikingly different even though both proteins contain all of the essential amino acids. For instance, in a serving of 100 grams (powder), casein contains 11.6 and 8.9 grams of glutamine and leucine, respectively. Whey contains 21.9 and 11.1 grams of glutamine and leucine, respectively. Both glutamine and leucine play critical roles in muscle protein metabolism. Thus, how amino acid composition ultimately affects muscle protein accretion is not clear (assuming that a dietary protein contains the entire complement of essential amino acids).

In addition, the second study suggests that repeated meals of whey protein may be the ‘ideal’ way to promote an anabolic state. It should be noted that the feeding pattern (13 meals every 20 minutes for four hours) is not a typical of ‘real-life’ eating. However, the evidence does suggest that multiple small feedings is superior to a single bolus feeding. This is likely due to the pattern of digestion. And lastly, casein and whey proteins are treated and metabolized differently with a single feeding of casein producing greater gains in protein accretion than the same sized feeding of whey.

On the other hand, a recent investigation showed no differences in the anabolic effects of whey or casein. Healthy volunteers were randomly assigned to one of three groups. Each group consumed one of three drinks: placebo (PL; N = 7), 20 g of casein (CS; N = 7), or whey proteins (WH; N = 9). Volunteers consumed the drink 1 h after the conclusion of a leg extension exercise bout. They discovered that the Ingestion of both CS and WH stimulated a significantly larger net phenylalanine uptake after resistance exercise, compared with the PL (PL -5 +/- 15 mg, CS 84 +/- 10 mg, WH 62 +/- 18 mg). Amino acid uptake relative to amount ingested was similar for both CS and WH (approximately 10-15%). Thus, the acute ingestion of both WH and CS after exercise resulted in similar increases in muscle protein net balance, resulting in net muscle protein synthesis despite different patterns of blood amino acid responses.(1)

At least from this limited data, one can reasonably conclude that casein protein as a sole protein source (versus whey) is either more anabolic or not different. What this means in a practical sense is not entirely known. However, one could speculate that if you were to consume a single protein source for gaining muscle mass, casein may be preferable over whey.
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jessica1045 · Joined: 30 Oct 2006 Posts: 17 Location: UK

"""when they looked at the ‘net leucine balance’ over the 7-hour time period after ingestion, casein ingestion resulted in a significantly higher net balance (i.e., post-feeding protein deposition was greater).""
i would think its much more difficult to get the amount of protien need to gain mass because casien is digested slower and would also make you want to eat less and that could effect your intake of overall nutrience throughout the day. i always thought it would be best to consume a form fo casien in your last meal beacuse it is digested slower.
what do you think?
also i couldn't understand was the pourpose of this study to find which protien is best to remain in an anabolic state or was it to specifically target how which type protien is used and stays in the body the longest?

""One last note regarding dietary protein; it should be noted that there is no evidence that consuming a diet high in protein has any adverse effects.""

your so right about that, i hate it when i read, and hear people say that high protein diets can harm kidneys. i doubt most of the people who say that know that protien is an active trasport, which seems to be a logical bases for there argument but it gets very annoying. i think i read some where there when you consume more protein you body responds to it by actully proccsing the protein more effictly. i'll try to post a link when if find it.

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birangela · Joined: 30 Oct 2006 Posts: 11 Location: uk

"""Keep in mind that these were not compared to consuming whole food meals...which I would rate along side casein..except the whole food meals have a more complete nutrient/vitamin/mineral/antioxidant/ etc profile... ""
i see so foods such as meat would also render a high net leucine, or dose this only apply to foods such as milk and cheese ?
also do you think you would get a better result if you drank a shake which contained a high amount of casien or if you adds foods that contained casien to your last meal?
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maria ross · Joined: 30 Oct 2006 Posts: 16

"i get it now, thanks for the clarification dan.
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Jafri · Joined: 06 Nov 2007 Posts: 5

i would prefer casien in comparison to whey protein.