Whey protein remains the most popular type of protein supplement favored by bodybuilders and athletes. Although whey protein has been around for over 100 years in less palatable forms (explaining why they never became popular) the first popular brand of whey was called Designer Protein, produced by Next Nutrition in the early 90s. Unfortunately, the claims made for this protein supplement in ads for the product often consisted of more hyperbole than fact. For example, one early advertisement for Designer Protein claimed that it had a biological value of 150, which was not possible. However, whey does possess the highest biological value of any protein at 105, which refers to its ability to support growth, in this case of animals. Whey is one of two primary proteins that exist in milk. Milk contains 80% casein and 20% whey. These proteins differ in their absorption characteristics. Whey is rapidly absorbed and peaks in the blood in about an hour following oral ingestion. Casein, however, curdles in the stomach following oral ingestion and the amino acids contained in casein are released gradually over about a 7-hour time span. What this means in a practical sense is that whey may be superior for promoting muscle protein synthesis following training because it rapidly provides the amino acids required for muscle protein synthesis (MPS). These amino acids are essential amino acids, meaning that they must be supplied in the diet and cannot be synthesized in the body. However, this doesn't mean that the other amino acids that are not in the essential category aren't important. These other amino acids not classified as essential include glutamine and taurine, both of which provide many health benefits.
Casein, because of its extended-release of amino acids, is thought to provide more anti-catabolic activity in muscle compared to whey. Indeed, a few published studies found that if 40 grams of casein protein are consumed after an evening workout and prior to sleep, it provides more of an anabolic effect in muscle compared to not ingesting any protein prior to sleep. Some other studies have disputed this finding, but it does make sense to have amino acids circulating in the blood following training. While MPS is considered most important for promoting increased muscle mass and strength gains, an often overlooked fact is that prevention of muscle protein breakdown is equally important, and that is where casein excels. In addition, as we shall see, ingesting the non-essential amino acids is now known to also blunt muscle protein breakdown, even though they don't promote MPS.
If the rapidity of essential amino acid uptake in the blood determines the extent of MPS and is the reason why whey protein is considered the best type of protein to promote MPS, wouldn't ingesting free essential amino acids produce an even greater anabolic effect than whey since the free aminos are even more rapidly absorbed than whey? This notion appears to . . .