Essential Amino Acids?

Today's ASK Doctor T: Essential Amino Acids

Question: What is it I tell someone when they claim you need to get the essential amino acids from this or that source?  I wish I could be logical with them and talk about all the countless other animals who are healthier and bigger than we are living entirely on plant life.  It is not that simple...

Short Answer: “Essential” amino acids are found in all plants and are just a small part of protein synthesis. “Non-essential” amino acids, also found in all plants (but much more so in animal protein) are utilized in much greater quantity because they are much more important for the body (in terms of quantity).

In fact, most of the “essential amino acids” eaten by mammals are converted in the body to “non-essential” amino acids, and only small amounts of “essential” amino acids remain in their original form. Therefore, “essential” aa’s are much less used in the building of proteins in the body and thus are much less “essential” then the “non-essential” amino acids.

The commonly-used nomenclature is therefore misleading and incorrectly interpreted by ignorant people (gym monkeys included...) who know nothing about biochemistry and assume that the adjective “essential” gives quantitative importance to the aa it describes. That assumption would be correct only in common layperson’s language, but is not correct in biochemical language. In biochemical language, “essential” does not mean “important” - it only means that the body can’t synthesize the amino acid by itself (even if its needed by the body in very small amounts that are found more than sufficiently in plant foods), and therefore must obtain it from food. These misleading biochemical adjectives are based on long tradition, not on accurate quantitative reality.

A more accurate, more descriptive terminology for amino acids, based on modern knowledge, would be “synthesizable” (for “non-essential amino acids”) and “non-synthesizable” (for “essential amino acids”). That’s much less confusing, because it does not assign “importance” - although obviously the synthesizable aa’s are far more important quantitatively - why would our cells retain the biochemical pathways needed to manufacture them  (from non-synthesizable aa’s) and expend so mush energy in their production, despite their availability in plant and non-plant food? The so-called “essential amino acids” are much less important quantitaively, therefore we don’t need to have metabolic pathways and expend energy to manufacture them!

I hope this answer is clear- please let me know if it isn’t and I’ll re-write it, since it’s important to explain these concepts to the public. Thanks for bringing it up!

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