On Thu, 7 Jan 1999, Ken Stuart wrote:

> A cow eats vegetable matter.
>
> It then does one of two things with that ingested vegetable matter:
>
> (1) It makes muscles and fat out of it.
>
> (2) It makes milk for its calf out of it.
>
> How can the milk be "foreign protein" and the muscle is not?

Well, the milk proteins and the muscle proteins are different.
The "foreignness" is not inherent in the proteins; it is a
function of how the human immune system responds to them.  The
cow harvests the amino acids in the food it eats and builds new
proteins, some of which are are supposedly identified by our
bodies as foreign.  This, at least, is the Neanderthin theory.

Having said that, I have to add that Neanderthin does not provide
an operational definition of what counts as a foreign dietary
protein.  It's not the same as a "non-self" protein, since *all*
food proteins are non-self (unless one practices
auto-cannibalism).  Theoretically, food proteins are completely
digested, i.e., broken down into their constituent amino acids,
and these are not foreign.  Lysine from a cow is the same as
lysine from wheat germ.

That's theoretically.  But there is reason to believe that some
small amount of intact protein or protein residue can pass
through the intestinal lining into the blood, at which point it
could trigger an immunological response.  But the bottom line is:
whether a given protein is foreign depends upon what *your* body
does with it.

Todd Moody
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