On Fri, 20 Oct 2000, David Karas wrote:

> Every species on this planet except for us eats
> all of their food uncooked. It seems to me that they look healthier than we do.
> Do they know something that we don't?

This may be a point where blood type theory has some validity.
For some reason (some pleiotropic gene, I guess) people with type
O blood secrete significantly more stomach acid than people of
type A or B.  Dogs and other carnvores secrete more of it than
humans of any blood type.

Although Peter D'Adamo asserts that this is relevant to "protein
digestion," I am unable to confirm this.  Protein is not digested
by acid, but by protease enzymes.  The function of stomach acid
is not well understood, but one plausible theory is that its
primary function is to kill bacteria on foods, especially
scavenged, semi-spoiled meat.

And although Peter D'Adamo is wrong to suggest that type A blood
"appeared" more recently than type O blood, he is correct to
point out that it *proliferated* more recently -- starting about
40,000 years ago, I believe.

So my theory is this: Prior to extensive use of fire for cooking
meats, the A blood type was disadvantageous, because it is
correlated with lower stomach acid levels, making people less
able to cope with bacteria in meat (and other foods) and thus
more susceptible to food poisoning and systemic infections.  When
food began to be cooked routinely, the fire did most of the work
of destroying the surface bacteria, so the A blood type was no
longer a liability.  From that point on it began to spread though
the human population until it was almost as common as type O.

So the moral of the story is: If this reasoning is correct, it is
cooked meat, not vegetarianism, that made type A blood viable.
And that implies that people of type A should be more cautious
about the bacteria in raw meat than type O people have to be.

It's just a guess.  The correlation between stomach acid and ABO
type is well documented, however.

Todd Moody
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