Essential Amino Acids


Hi there

When talking about limiting amino acids what does it really mean...
What I think it means is say we have a food eg wheat it has all the essential amino acids (aa) in it except one of them is not in the correct amount we need...does this mean that all the other aa present will not work or they will work but just limited to the limiting aa and the other amount will be degraded??--is this correct?

Also if essential aa needs are so low then would it be possible to say eat a burger (which said had 4/9 essential aa) and then say another food which had the other 5 essential aa would that be OK for the daily requirement? really we only have to eat a tiny bit in everyday life to get the aa??

Thanks in advance_06er

jim mcnamara

You're talking about complementary protein sources in the human diet.
Complete protein, like egg, has a well balanced array of amino acids, wheat flour does not have such a nicely balanced array... So, when you are using a poorly balanced protein as your primary protein source you need to add a different protein source that has more of the missing amino acid - example: beans and corn.

Assume humans require just three amino acids : a, b, and c.
And that a perfect protein (the usual gold standard is egg) is 10 units of a, 10 units of b, and 10 units of c.

Then when you eat protein that is a-1 b-10 c-10, you are short on a.
But if you also eat protein at the same time a source that is a-8 b-1 c-1, you get a more nearly complete protein intake.

If you are really interested, play with NAL from the USDA. The data in it is sometimes used to construct those "nutrition labels" for foods sold in the US and elsewhere, when the company packaging the food doesn't have access to a nutrition analysis laboratory.

Thanks fo rthe reply
But say you eat protein that is a-1 b-10 c-10, would 'b' and 'c' still "work"


Staff Emeritus
Science Advisor
Gold Member
Yes, the amino acids you get will "work" for making proteins that only require those and the non-essential amino acids, and a small percentage of the ones you are deficient in will be made. But, unused amino acids don't linger around, so you can't eat half of them today and the other half tomorrow and be okay. You need to have all of them in your diet each day to build all the proteins you need for normal body function.
Moonbears example is a good reason why most Vegans look like crap.. especially the athletes.

it is EXTREMELY difficult to get enough protein without animal products. Prior to the industrial age it would have been impossible.

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