How do gut bacteria actually make it to your intestines with the hydrochloric acid produced by the stomach in the way?

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How do gut bacteria actually make it to your intestines with the hydrochloric acid produced by the stomach in the way?

In: Biology

First, the stomach doesn’t constantly produce acid. That only happens when you’re digesting food.

Second, the bacteria in your intestines don’t have to pass through the stomach. They live and grow in the intestines, and it would actually be pretty bad if they get anywhere else in the body. The *E. coli* outbreaks you might have heard about in the news are caused by a germ that normally lives in the intestines, but if they’re ingested and digested you’re gonna have a bad time.

The hydrochloric acid in your stomach is usually heavily diluted in the first place, and only long-term exposure can erode their membrane away. Most, however, reside in your gut lining, which has a nice, thick layer of mucus to protect then from your stomach fluids. Some of the mucus gets washed down when the contents of your stomach move from your stomach to the small intestine, where bile acts as a general transmitter for bacteria to your large intestine. Basically, your gut bacteria spreads throughout your GIT due to pure luck. Pretty good luck for the both of you, too, because you have a mutual symbiotic relationship.

A lot of bacteria die in the stomach, but a few make it through. Some are partially resistant to the acid. A=Others can produce spores that are resistant to the acid. Some are just so abundant in food that a few make it through by shear luck.