C. Kuni wrote:
> We watched "Walking with Cavemen" last night. (Netflix.)  Very interesting portrayal of early man.  I learned a lot, though I'm not sure how much of the film was fact and how much was speculation.  The climate/food connection was especially interesting to me.  Also, it looks like we were meat eaters for quite some time before we ever cooked our food.  So why do we have so many problems with e-coli and bacteria today?  Any thoughts?
> CK
>   

This may be an area where the "blood type diet" theory has some merit.  
It is a fact that people with type A blood make less gastic HCl than 
those with type O blood.  It also appears to be true that the frequency 
of type A blood in human populations increased about 40,000 years ago, 
although there's no reason to suppose that it *began* then.  So that 
raises an interesting question:  What might have happened 40,000 years 
ago to make the world more hospitable to those with type A blood, 
resulting in an increase in the relative frequency of that phenotype?

Note that both type As and type Os make *enough* HCl to activate the 
proteolytic enzymes.  To my knowledge, there is no evidence for the 
claim that type As don't make enough HCl to digest much meat.  But type 
Os seemingly make more than enough, suggesting that the additional HCl 
may have provided another advantage, at least until about 40,000 years 
ago.  So one theory is that gastic HCl also serves to kill food-borne 
microorganisms (dogs and other carnivores also produce high levels of 
HCl), and the cooking of meat became common, this defense became less 
important, resulting in a proliferation of the type A phenotype that, 
prior to cooking, was held back.

It would be useful to see if type As have more problems with E. Coli 
etc. today than type Os do.  That would be predicted by my theory.

This is purely speculative, but you did ask for *thoughts*!

Todd Moody
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