[alan aragon]

to all,

we cannot begin to think we know all the properties/behavior of either whey or casein, because we simply DON'T. it's never wise to put sets of data in their neat little boxes, & keep thinking in those narrow terms (we are all guilty of this; it's human nature to over-simplify).. too many people put whey in the "too quickly absorbed/too quickly gone" category, while others put casein in the "too slowly absorbed, too slow to cause protein synthesis, but fine for anticatabolism" category -- and basing all conclusions & applications on that. furthermore, net muscle gain isn't all about protein synthesis by itself, the too-often overlooked other half of the equation is suppression of protein degradation, or anticatabolism... well, what does the research say? let's take a look:
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Tipton KD, Elliott TA, Cree MG, Wolf SE, Sanford AP, Wolfe RR. Med Sci Sports Exerc. 2004 Dec;36(12):2073-81. Ingestion of casein and whey proteins result in muscle anabolism after resistance exercise.

PURPOSE:: Determination of the anabolic response to exercise and nutrition is important for individuals who may benefit from increased muscle mass. Intake of free amino acids after resistance exercise stimulates net muscle protein synthesis. The response of muscle protein balance to intact protein ingestion after exercise has not been studied. This study was designed to examine the acute response of muscle protein balance to ingestion of two different intact proteins after resistance exercise. METHODS:: 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. Leucine and phenylalanine concentrations were measured in femoral arteriovenous samples to determine balance across the leg. RESULTS:: Arterial amino acid concentrations were elevated by protein ingestion, but the pattern of appearance was different for CS and WH. Net amino acid balance switched from negative to positive after ingestion of both proteins. Peak leucine net balance over time was greater for WH (347 +/- 50 nmol.min.100 mL leg) than CS (133 +/- 45 nmol.min.100 mL leg), but peak phenylalanine balance was similar for CS and WH. 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%). CONCLUSIONS:: 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.
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^^the point here is in bold. if you read the results, whey had a superior ability to facilitate leucine uptake, while casein slightly edged out whey's ability to facilitate phenylalanine uptake, but neither was deemed superior across the board.

now for the ONLY study on CHRONIC EFFECT (effect over extended duration, not acute/immediate effect) that really convinced me that casein was not a second-rate protein, but possibly superior to whey:
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Demling RH, DeSanti L. Ann Nutr Metab. 2000;44(1):21-9. Effect of a hypocaloric diet, increased protein intake and resistance training on lean mass gains and fat mass loss in overweight police officers.

We compare the effects of a moderate hypocaloric, high-protein diet and resistance training, using two different protein supplements, versus hypocaloric diet alone on body compositional changes in overweight police officers. A randomized, prospective 12-week study was performed comparing the changes in body composition produced by three different treatment modalities in three study groups. One group (n = 10) was placed on a nonlipogenic, hypocaloric diet alone (80% of predicted needs). A second group (n = 14) was placed on the hypocaloric diet plus resistance exercise plus a high-protein intake (1.5 g/kg/day) using a casein protein hydrolysate. In the third group (n = 14) treatment was identical to the second, except for the use of a whey protein hydrolysate. We found that weight loss was approximately 2.5 kg in all three groups. Mean percent body fat with diet alone decreased from a baseline of 27 +/- 1.8 to 25 +/- 1.3% at 12 weeks. With diet, exercise and casein the decrease was from 26 +/- 1.7 to 18 +/- 1.1% (8% decrease) and with diet, exercise and whey protein the decrease was from 27 +/- 1.6 to 23 +/- 1.3% (4% decrease). The mean fat loss was 2. 5 +/- 0.6 (placebo), 7.0 +/- 2.1 (casein) and 4.2 +/- 0.9 kg (whey) in the three groups, respectively. Lean mass gains in the three groups did not change for diet alone, versus gains of 4 +/- 1.4 and 2 +/- 0.7 kg in the casein and whey groups, respectively. Mean increase in strength for chest, shoulder and legs was 59 +/- 9% for casein and 29 +/- 9% for whey, a significant group difference. This significant difference in body composition and strength is likely due to improved nitrogen retention and overall anticatabolic effects caused by the peptide components of the casein hydrolysate.
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^^in this study, the casein group had double the fat loss compared to the whey group, as well as double the amount of lean mass gain. not only that, but the casein group also had about double the strength increase compared to whey.. what more do you want? lol.. there's another study by lands, comparing a whey supplement "immunocal" with a casein placebo, where they found better effect on endurance, antioxidant activity, & peak power in the whey group, but the study showed nowhere near the superior whoopass that the demling study (above) showed casein to have for bodybuilding purposes. furthermore, the demling study wasn't a biased product-based vested interest study either.

there's more milk studies in progress, & more are bound to support my casein. get it? case? casein?

i recommend having both, & stop worrying about casein slowing down the absorption of whey. that's too simplistic, because it might not matter at all.. as i've mentioned before, you might be better off worrying about whey getting in the way of casein. but once again, have both.