There are many sources of protein. Eggs, beef, casein and soy protein are all quite common. But when serious athletes and bodybuilders seek optimal nitrogen retention, nothing is more effective than whey.
For endurance and strength/power athletes to remain in positive nitrogen balance, studies indicate that protein levels of up to 2.0g per kg body weight per day may be required. This additional protein intake can cause metabolic stress to organs, unless the protein source has a high Biological Value (BV). The higher, the better. And whey protein has the best biological value of them all.
Biological value basically measures a protein's quality by comparing the body's nitrogen levels absorbed from eating and those preserved following digestion. The top-ranking value for whey reflects its easy digestion and excellent metabolic efficiency.
Similar to BV, the Protein Efficiency Ratio (PER) measures quality by assessing the degree to which a protein is efficiently utilized by the body. Whey protein's PER is much higher than most other sources of protein.
BV and PER Ratings of Selected Proteins
Protein |
BV |
PER |
whey |
104 |
3.4 |
egg white |
88 |
2.5 |
milk |
85 |
2.7 |
soy |
59 |
2.0 |
corn |
33 |
1.2 |
Whey protein also has the highest rating according to the PDCAAS ranking system, which measures protein quality based on the body's amino acid requirements. PDCAAS stands for Protein Digestibility Corrected Amino Acid Score, and as such, assesses a protein's essential amino acid profile, nitrogen composition and true digestibility. PDCAAS finds whey protein—unlike vegetable proteins—to have no limiting essential amino acids to detract from quality—whey actually has an excess of them!
PDCAAS of Key Proteins
Protein Source |
PDCAAS Score |
Whey protein isolate |
1.14 |
Casein |
1.00 |
Milk protein isolate |
1.00 |
Soy protein isolate |
1.00 |
Egg white powder |
1.00 |
Ground beef |
1.00 |
Canned lentils |
0.52 |
Peanut meal |
0.52 |
Wheat gluten |
0.25 |
In fact, whey protein contains the highest concentration of Branched Chain Amino Acids (BCAAs) available from any natural food protein source: ~26%! That includes leucine, isoleucine and valine. Evidence suggests that the more BCAAs consumed, the better preserved muscle mass is during and after exercise. BCAAs are also believed to delay fatigue, so you can train more intensively for longer periods of time. And for after that killer workout, evidence suggests that BCAAs can aid recovery and help you revitalize.
Whey is a rich source of other amino
acids, too. Among them are arginine and lysine, which may stimulate growth hormones and lead to an increase in muscle mass and a decline in body fat. Additionally, whey's bioavailable calcium can reduce stress fractures and prevent bone loss in hypoestrogenic female athletes.
And finally, bodybuilders take note: whey is a superior anabolic protein. It rapidly enters the bloodstream and reaches muscles faster than other protein sources, allowing muscle tissue growth to occur sooner.
Why whey? Why not?!!
To become a savvy consumer in the whey protein market, learn about different whey processing techniques in our section on Whey Science.
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