David Ross wrote:
> This has long puzzled me - is anyone clear about why the >protein in "foreign" animal flesh might be less problematic?
>
> David

My guess: simply because we don't happen to be allergic to the proteins
in the flesh. And that would be because we have had hundreds or even
thousands of millennia to adapt to them. Milk consumption being more
recent we have had less time to adapt. There are millions of proteins,
and what I understand is that all of the ones you consume from another
species are foreign, are slightly different from the ones you synthesize
in your own body. The question is whether you have an allergic reaction
or not. I think a key part of this equation is that whole proteins do
get through into your bloodstream. In science classes we were taught
that proteins are all broken down into amino acids before getting
absorbed. If that were true, there could never be an allergic reaction
to a food. In fact, "leaky gut" is a very common condition, to varying
degrees in adults, and may be an essential part of the design in infants
who need to absorb certain factors from their mother's milk, but will
have a problem when exposed to foreign substances, which would never
have happened during our evolutionary development.