When it comes to protein, there's a lot more to consider than people often realize. First, there's the amino acid profile. Then you have the issue of any other nutrients that might be kicking around in your tub.
Tying it all together, though, we have bioavailability. While this is sort of a strange word, bioavailability refers to how easy (or difficult) it is for your body to absorb and use a specific nutrient. In this case, we're looking at how readily protein is used.
Whey protein is, by nutrient, an incredibly fast protein source complete with pretty impressive bioavailability. In its natural state, your body is able to put that protein to use quickly and get a huge amount of benefits from it. But, again, that's in its natural state.
What about when people start messing around with it? A fairly common form of whey – called whey protein isolate – is processed to remove the sugars and fats, increasingly the protein concentration of the end-product. But what does this do to the bioavailability of the protein?
Denaturing and Devaluing
To fully understand the topic, however, we need to understand what happens to whey protein isolates that make them different. As mentioned, perfectly good whey protein concentrate is exposed to more-than-the-usual processing to remove “unwanted” nutrients.
The exact technique used here varies. This process – whichever one they pick - doesn't just get rid of fats and sugars, though. It also degrades the natural three-dimensional shape of several peptides that naturally occur in whey and offer a variety of health benefits.
In whey protein isolate, these substances are either removed altogether or made useless. According to a 2004 review published in the Journal of Sports Science and Medicine, this denaturing does not just impact the bioavailability of these small peptides – entire proteins are affected.
The processing, reports the article, reduces the overall bioavailability of the proteins found in whey protein isolate by breaking down their structure and weakening the bonds that hold them together.
A Better Whey
So, yes, whey protein isolate has a higher concentration of protein than whey protein concentrate. (Which is more than a little confusing.)
In the end, though, does that really matter?
Whey protein concentrate is stuffed with substances that can greatly improve your digestive, immune and cardiovascular health – many of which are destroyed during the process that creates isolate. Those that are not completely destroyed are removed when the fat that they are bound to is removed.
Additionally, the techniques that increase the protein concentration also harm the structure of the proteins to the point that your body has a harder time using them. Whey protein concentrate, however, exists the form that it is meant to operate in and, therefore, is quickly absorbed by your body without much fuss.