If your stomach acid so acidic that it can melt almost anything, why do other foreign organisms and objects still pass through like nothing happen? Why do tapeworms continue to survive and other bacteria?
In: Biology
If stomach acid was as strong as you seem to think, the stomach lining would not hold, and throwing up once would melt your throat and mouth, killing you fairly painfully and quickly… It’s a concentration issue, not a matter of acid type, though. Hydrochloric acid, the primary component of stomach acid, is quite potent in pure form, but it’s pretty diluted. Heck, the same acid is used as a food additive, in very low concentrations. In the words of Paracelsus, the poison is in the dose.
Tapeworms have a secondary epidermis which excretes and coats them with a similar compound to the mucus that lines our stomachs. It quickly neutralizes the pH of our gastric acid at a cellular level. Also, our stomach will eject its contents after a certain amount of time. Some things require much longer to be broken down fully, and the stomach doesn’t hold on that long. Fibrous foods such as beans, corn, grains and seeds will usually be left partially intact. This is a good thing, as the extra bulk helps stimulate the intestinal walls and form healthier stool.
Your stomach is actually not that acidic-about 1.5 to 3.5, or comparable to lemon juice. There are many things that are resistant to stomach acid, including organisms. The organisms that have evolved to survive our stomach acid are those that specialized to infect humans. The ones that weren’t able to survive that trip didn’t reproduce, while the ones that did went on to pass those genes conferring acid resistance to the next generation.
Lots of focus on the acidity of the stomach and too little focus on the tapeworm going on here.
Tapeworm eggs/larvae (can’t remember exactly) are inside a cyst, basically a little fatty bubble, inside of meat. When that meat is eaten, the fatty wall of the cyst is broken down in the stomach, but the tapeworm is safe inside it’s bubble. It can then move into the intestine, which is a much friendlier environment for a parasite.
For other pathogens, it depends a bit. Salmonella actually is very sensitive to our stomach acid and will not survive it if you just swallowed a solution with it mixed in. However, if that bacteria can hide out in some meat you eat (fat/protein), it can survive the acidity and move on the gut to wreak havoc.
A few years ago I swallowed an Osterizer blender blade. It never came out the back end. I doubt the acid could eat a stainless blade like that, but I hope it did.
Stomach acidic can melt *almost* anything. There’s still lots of stuff that it can’t dissolve. For example, the lining of the stomach itself. Some foreign organisms and objects have a similar lining that allow them to survive the stomach acid
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