Is the protein in gluten usable to the body [closed]

Question

On average, most brands of protein powder contain around 70 to 80 grams of protein per 100g.

Vital wheat gluten flour (which is 100% gluten) contains around 75g protein per 100g. On the surface, this seems pretty good to someone who is interested in increasing their protein intake.

However, I have heard from some sources that gluten cannot be completely digested by the body. If this is true, does only part of that protein count for body building purposes?

Gluten is a protein. We have proteases for it. We can break it down. We just can’t break it down completely: one of the pieces, named gliadin, does not get broken. [1]

If gliadin does not get broken, then is all of the protein content of 75g per 100g of vital wheat gluten actually usable (ie. Gets absorbed) by the body?

More specifically, are any of the major protein constituents of gluten (such as gliadin) not absorbed by the body? And if not then how much of the protein content of gluten is comprised of these constituents?

To clarify, I am not talking about using vital wheat gluten flour to make a protein shake, it would clearly just congeal into a ball of gluten. I mean for using the gluten flour in recipes, for example to make seitan.

Seitan prepared to western recipes commonly adds a lot of other ingredients to the seitan to flavour it. However the traditional Chinese preparation of seitan called 面筋 (Miànjīn) is made simply from pure gluten flour and water, and then cooked by steaming. It can merely be eaten with rice and in this way could form a large portion of the protein content of a meal.

I am also specifically asking in the case of normal people without coeliac disease or gluten intolerance.

1:https://www.forbes.com/sites/quora/2017/03/03/is-it-true-that-humans-cant-properly-metabolize-gluten/amp/

Answer 1

If you read the article again you'll find this passage:

Gluten is a protein. We have proteases for it. We can break it down. We just can’t break it down completely: one of the pieces, named gliadin, does not get broken. This is not improper digestion, that’s just how we digest it.

So the article says that that's just how things work; we don't need to break everything down into atoms. That's not quite proof our bodies can use it, but is there any reason to believe they can't? I'd say no. Googling for "gliadin" doesn't yield anything specific about the human body not being able to use it, and seitan is a commonly recommended protein source for (and by) vegans who lift.

However, unlike the whey and soy proteins you'll find in protein powders, gluten doesn't have all the essential amino acids your body needs, so you'll need other protein sources, too. For example, the amino acids in legumes are a good complement to those found in grains, so you'll want to balance your seitan intake by also eating beans, lentils or similar. As usual, a varied diet tends to be a good thing.