Whey protein stimulates postprandial muscle protein accretion more effectively than do casein and casein hydrolysate in older men

Abstract

Whey protein stimulates postprandial muscle protein accretion more effectively than do casein and casein hydrolysate in older men. This effect is attributed to a combination of whey's faster digestion and absorption kinetics and higher leucine content. This trial was registered at clinicaltrials.gov as NCT00557388.

The muscle protein synthetic response to the combined ingestion of protein and carbohydrate is not impaired in healthy older men

“…Previous work from other labs (Tang et al 2009) as well as ours (Pennings et al 2011a) has shown that ingestion of whey protein results in a greater muscle protein synthetic response when compared with casein. Therefore, we expected that potential differences in the muscle protein synthetic response to protein ingestion between the young and older subjects would be most prominent after consuming casein as opposed to whey protein.…”

“…13 C]phenylalanine-labeled protein, specifically produced by the infusion of large amounts of tracer in a lactating Holstein cow (Pennings et al 2011c;van Loon et al 2009b), we are able to detect the appearance of dietary protein-derived phenylalanine in the circulation (Fig.3) and assess its subsequent incorporation in skeletal muscle protein Koopman et al 2009b;Pennings et al 2011a;Pennings et al 2011b;. Two hours after ingestion of the protein, skeletal muscle protein already showed a substantial increase in [1-13 C]phenylalanine enrichment (0.0071±0.0016 and 0.0072±0.0013 MPE in the young and older group, respectively; P=0.97).…”

“…As presented in previous works from our laboratory (Pennings et al 2011a, b;Pennings et al 2012;Koopman et al 2009a), we applied specifically produced intrinsically L-[1-…”

Regulation of muscle protein metabolism by nutrition and exercise

“…A comparison of whey and casein in milk protein shows that although whey is rapidly absorbed and exported from the gastric environment because of its acidic character, casein intake results in a lower peak blood leucine concentration because it is coagulated and precipitated by gastric acid and more slowly exported from the gastric environment. Previous studies comparing the effect of whey and casein showed that whey intake induced higher muscle protein synthesis compared to casein intake both in a resting state and after an acute bout of resistance exercise 32) . Therefore, the influence of digestion and absorption characteristics should be considered when we consume protein as a meal and/or functional food.…”

Future Challenges of Whey Proteins

“…The greater anabolic properties of whey than of casein are mainly attributed to the faster digestion and absorption kinetics of whey, which results in a greater increase in postprandial plasma amino acid availability and thereby further stimulates muscle protein synthesis. These findings have led to the development of the "fast" and "slow" protein concept (Doherty, 2003;Tang et al, 2009;Pennings et al, 2011).…”