Claim: Humans have an acidic stomach to kill off pathogens


Humans have unusually low pH for an herbivore. Therefore it's a sign we should be eating meat because our stomach pH is low in order to kill off pathogens and digest meat.

Problems With This Argument

1. Humans are unusual in a lot of ways

Many characteristics of humans are unusual, specifically because we are the only species that cooks their food. So the shapes of our jaws, faces, and teeth are very unusual for primates. So the fact that our digestive tract follows suit should be of little surprise, especially given how much things like the microbiome are affected by all these other differences.

It goes without saying that if you think you have some scientific evidence that shows that humans are "built for" eating animals (i.e. that they have the best health outcomes from this diet), the test for that would be based on the epidemiological data, not based on what you think you are inferring from some limited window of data from some particular minute aspect of human physiology. This would be an interesting observation that you could turn into a hypothesis that you could then test about the health claims, but this would not be good a priori evidence.

2. ...On a chemistry side note

It should be noted that pH isn't everything. Hydrofluoric acid (HF), (as seen on "Breaking Bad"), is known to be a ruthless chemical that is even used to etch glass. It certainly is a lot harsher than something like perchloric acid, which is relatively mild by comparison even though it would have a much lower pH because it is a "strong acid" and therefore the proton completely disassociates from the perchlorate ion. In addition, in chemical research settings, chemicals with relatively near-neutral pH, like hydrogen peroxide, can be used to clean glassware by breaking down and molecularly attacking contaminants, even though a pH measurement would not reveal that it is such an aggressive chemical. These are simple examples, but the stomach, with all of its emulsifiers and digestion enzymes, is an even more complicated system, so "low pH aggressive" and "high pH mild" is a highly simplified mental model of gastric chemistry.

3. Carnivores don't have the lowest pH

The lowest-stomach-pH animals are almost all scavengers, some of them exclusively scavengers. So it would seem this is a better argument for eating roadkill than for eating live animals.

4. This doesn't address the ethics

Even if we demonstrated that we could eat raw meat and be healthy, it would not demonstrate anything about the ethics of the situation.

Markdown - (copy 📋)
Rich Text
[Claim: Humans have an acidic stomach to kill off pathogens](