Different Sources of Protein Provide Different Amounts of the Essential Amino Acids

The high level of the bioavailable amino acid cysteine in whey protein compared to other protein sources also makes whey protein the obvious choise of protein source, as cysteine plays an essential role in human metabolism.

12/03/09 When choosing your source of protein, it is important to have in mind that different sources of protein provide different amounts of the essential amino acids.

The nutritive value of a protein depends upon its capacity to provide nitrogen and amino acids in adequate amounts to meet the requirements of an organism.  As shown in table 1 the nutritive value of whey proteins is high compared to other protein sources. 

Whey protein provides all the correct amino acids in approximate proportion to their ratios in the skeletal muscle, and is very rich on the essential amino acids lysine, methionine + cysteine and threonine. Also, whey protein contains a higher dose of branched chain amino acids (BCAAs: leucine, isoleucine and valine), than other protein sources (Table 2). In addition to a favourable amino acid composition, the whey has very high amino acid availability.

The high level of the bioavailable amino acid cysteine in whey protein compared to other protein sources also makes whey protein the obvious choise of protein source, as cysteine plays an essential role in human metabolism. An adequate supply is essential to the preservation of lean body tissue, particularly during exercise. Cysteine also plays an important role in the body’s antioxidant defense systems.

So when choosing whey protein to other protein sources, you get the most optimum amino acid composition along with a high amount of protein.