But how valid are these claims?
TL:DR - NO. Don't be scared of protein isolates homie!
Some of the more common 'risks' are:
1. They are denatured
The rebuttal to this comment could be “Umm, Yeah…so what?”
Whether there is some denaturing of protein during the isolation process is a complete non-issue. While it sounds scary, protein denaturing is a normal process, and many of the foods we eat all the freakin' time contain denatured proteins.
Denaturation is simply the process in which proteins lose the structure which is present in their native state. This occurs when acid, base, a concentrated salt, solvent or heat is applied to a protein chain.
Of course, that means denaturing a living protein in your body is a very bad thing! But in the food we eat, it is not so. The protein chain will be denatured and digested by stomach acid and gastric enzymes and broken down to its constituent amino acids which are then absorbed into the body and this occurs whether it is ‘denatured’ or not. Remember that when you cook food, some of its proteins become denatured. A visible example of this is the change in colour and opacity when you cook egg whites, which results from the proteins being denatured.
2. They are acidic
Another common claim is that isolates lack ‘alkalising mineral co-factors’ and thus, acidify your body.
This claim is as bogus as Bill and Ted's (second) Adventure...
The body has a remarkable ability to preserve its acid-alkaline balance. The body preserves normal acid-base balance via changes in respiratory rate and volume, and by excreting acid compounds via the kidneys and reabsorbing alkaline compounds. In most people, most of the time, these functions work to keep the body’s acid-alkaline balance within normal, healthy ranges. In fact, if the body were truly ‘acidic’ it wouldn’t last very long because a very tight range of pH is required for enzymes (the little proteins that help life-sustaining chemical reactions to take place) to do their job properly. There can be some ‘tapping into’ bone and muscle tissue to free up alkaline compounds to help buffer the blood if the diet is extremely acidic or if the other processes are somehow impeded. But this seldom happens to any detrimental degree if you are trying to eat a good diet that contains lots of 'alkaline' foods like vegetables and berries.
3. The body doesn’t ‘recognise’ protein isolate
This is one of the most bizarre claims that I hear regularly. I have even been told this by a medical doctor! She claimed that the body doesn't recognise protein and it therefore helps to make people fat. Hmmm. WTF?
Think about it this way; It would be nice if any food were not recognised…because then you could eat as much as you like of it and you couldn’t ever gain any weight!
However, that contention defies any semblance of logic. In the case of protein isolate specifically, we have good data showing high absorption rates of pea protein isolate from the digestive tract (over 89%),(1) and there are an enormous amount of studies showing that these proteins improve muscle protein synthesis and support muscle growth and maintenance.(2) If they weren’t ‘recognised’ there is no way they could do that. So, by extension, we must conclude that protein isolates are digested and absorbed easily, and are effectively used.
Protein isolates, are well absorbed and have a myriad of functional benefits that include improved satiety, and improved fat-loss and muscle gain. The claims that protein isolates are dangerous or detrimental to health are without any credible evidence.
1. Gausserès N, Mahe S, Benamouzig R, Luengo C, Ferriere F, Rautureau J, et al. [15N]-labeled pea flour protein nitrogen exhibits good ileal digestibility and postprandial retention in humans. The Journal of nutrition. 1997;127(6):1160-5.
2. Babault N, Païzis C, Deley G, Guérin-Deremaux L, Saniez M-H, Lefranc-Millot C, et al. Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein. J Int Soc Sports Nutr. 2015;12(1):3.