Something about vegetable proteins I dont understand. page

[Warmbear]

Heya, I was talking with my veghead sister in law and was asking about how they get enough protein in their diet and was told you do that by eating various kinds of vegetables so as to get a complete protein. I asked if she knew how much of the protein in plant matter was actually bio available to humans as we cant really digest the cellulose. She did not know how to answer and simply assumed that all the protein was there for us to use.

Can some one explain how this works? How is the vegetable protein delivered to our digestive tract and is it actually in a form we can make use of?

I found this bbc production that makes me think that not a lot of the protein can be used though they do not cover it specifically. Did Cooking Make Us Human ? (BBC Documentary) - YouTube

[Neckhammer]

Most vegetable protein scores less than 50 on the bioavailability scale. Eggs are among the the highest in bioavailability along with whey protein (scores 100). Next comes milk, beef and most other animal flesh....then beans and nuts and such....then vegetables and soy if memory serves.

[Warmbear]

yes but what does that mean? how do you calibrate such a scale?

[jfreaksho]

yes but what does that mean? how do you calibrate such a scale?

I can't answer this, but you also can do some research into the different kinds of amino acids that combine to form complete proteins. Soy is the only plant with complete proteins we can use. Other plants are missing vital amino acids that your body has to scavenge or acquire from other foods.

So I'm not really helping, but adding to the research needed to answer your question. Sorry.

[Velocity J]

These values are usually calculated in a lab by feeding subjects (not always human) specific sources of protein and then looking at either what gets excreted or how much weight the subject gained over the test period. Those numbers are then used to get a rough estimate of how much protein was actually utilized. In terms of what affects the body's use of protein from sources I'm not exactly sure.

Some of the scales also take into account the amino acid profile of a protein source and rate it not just on how much protein gets absorbed by the body but also how well the food provides the right amount of the different amino acids we need.

[magicmerl]

yes but what does that mean? how do you calibrate such a scale?

It means that the 'protein' levels of foods that have a low bioavailability score are lower than they look. Just like 'total carbs' includes fibre, when what we really care about it the bioavailable carbs (or 'net carbs'). Bioavailable protein is just 'net protein'.

I think that the 'incomplete proteins' arguement is a red herring, since you can easily form complete proteins by combining vegetable sources.