See, seems there's a meme floating around in some omnivore circles that personifies the title of this post: namely, that human production of hydrochloric acid in the stomach is proof that we are "meant" to eat meat, because herbivores don't produce HCl in their stomachs.
I've encountered it three times in online comments sections; once at Let Them Eat Meat; once at The Huffington Post; and most recently on the comments of a YouTube video featuring Jonathan Safran Foer. I've stopped counting the number of times I've heard it from meaty-mouths here in meatspace.
But, I did start to wonder where this embarrassingly moronic claim originated. So, I've been trawling the depths of Google and Bing on my quest to find out, and I think I nailed it down.
From what I can tell, the meme got its start with The Myths Of Vegetarianism by Dr. Stephen Byrnes. Check out paragraph 2 of his Myth #11:
Some vegetarian groups claim that since humans possess grinding teeth like herbivorous animals and longer intestines than carnivorous animals, this proves the human body is better suited for vegetarianism (123). This argument fails to note several human physiological features which clearly indicate a design for animal product consumption.
First and foremost is our stomach's production of hydrochloric acid, something not found in herbivores. HCL activates protein-splitting enzymes. Further, the human pancreas manufactures a full range of digestive enzymes to handle a wide variety of foods, both animal and vegetable.
Further, Dr. Walter Voegtlin's in-depth comparison of the human digestive system with that of the dog, a carnivore, and a sheep, a herbivore, clearly shows that we are closer in anatomy to the carnivorous dog than the herbivorous sheep. (124)I don't know much about Byrnes; he's described as a naturopathic doctor (warning klaxon #1), recommended the Weston Price Foundation (klaxon #2... and no, I will not link), and apparently did good work for HIV/AIDS patients in Hawaii (genuine applause) before dying suddenly of a stroke in 2004. Nor do I know where Byrnes came up with this silly idea about herbivore digestion. But since the encounters I've had with this meme have all been worded almost exactly like the emphasized paragraph above, I think I can safely blame Byrnes for giving this one legs.
He should have known better, and shame on him for starting it. More shame on those in "paleo" circles who should also know better and should have corrected him on this point long ago. I mean, they wouldn't want to embarrass themselves and their cause by spouting provably false information and then getting publicly called on it, would they?
Like suffering and empathy, gastric secretion of HCl is conserved in all vertebrates. Without knowing which specific digestive enzymes Byrnes was referring to (though I suspect it's elastase, which I've heard more than one carnist apologist invoke), I can still safely predict that the same is true for his pancreas claim, as well.
To put it plainly: yes, herbivores do produce hydrochloric acid in their stomachs. So do carnivores and omnivores. There's nothing particularly noteworthy about it; it's just part of all vertebrates' fishy ancestry.
The fact Byrnes was pointing to, without seeming to realize it, is that carnivores and herbivores produce differing amounts of HCl, reflecting their different trophic strategies. Hominins fall here, as in most other ways, somewhere in the middle range, making them generalists or "omnivores." Which is a perfectly valid point to make when arguing against the "man-is-a-natural-vegan" claim; it's too bad a guy with a Dr. in front of his name didn't possess enough of a grasp on basic biology to spot such a simple error, and thus lured himself and his readers into looking like bozos. But then, that's what you get for credential-mongering.
Fact-checking: it's the science-y thing to do, friend paleos. Given your self-chosen moniker, you guys really ought to be more careful. Call this one a gift.
NOTE: I'm not planning on Idiotic Omnivore Claims becoming a regular feature at PaleoVeganology, but I will keep my peepers peeled nonetheless.