The Biological Value (BV) scale is a standard way to measure the proportion of protein that is absorbed from a food by the human body. A specific mathematical breakdown of how the scale works would be out of scope for this article, but for those interested, please see its Wiki article.
As a measure of protein absorption, the BV scale has evolved over the years, as all scientific measurements do. It is used widely by studious body sculpting pros seeking to maximize their muscle-growth rates and build muscle quickly: the higher a protein supplement or food’s BV rating, the more valuable it is supposed to be for building muscle.
However, the Biological Value scale is based solely on observed absorption of nitrogen and therefore does not actually tell the user how readily the protein is broken down and used in cellular processes such as building muscle within the body.
Additionally, the testing system of the scale is questionable because it relies on test subjects with artificially protein-dense diets. This is a problem because when a mammal consumes more protein than necessary, its absorption of any protein in foods is reduced. And the reduction of absorptive power occurs unevenly across the spectrum of protein types, so the BV scale is definitively weighted against certain proteins.
The BV rating of any given protein is affected by three major factors (in descending order of importance):
- Amino acid composition
- How and if it is prepared/cooked
- Vitamin and mineral content
Because the preparation, age, and storage of a food or protein supplement can affect its nutritive content, often BV tests require the manual addition of vitamins to the food in order to test it accurately. But this doesn’t always occur, and when it does it is inconsistent. This means that the actual protein absorption as measured in a Biological Value test is often different from its real-world protein utility.
In other words, while the BV test can be a useful shorthand reference point for determining how effective regular foods, protein shakes, and protein bars will be in building muscle, it doesn’t guarantee accurate measurement. If you’re extremely concerned about your protein intake levels, you should cross-reference the food or supplement’s BV rating with its results in other tests, and also pay close attention to how your body seems to react to consuming the food because no two bodies are exactly the same.