How does leaky gut cause anxiety and depression?


I have SIBO (small intestine bacterial overgrowth) and it’s a well known thing that having that overgrowth can cause depression and anxiety. But how?

In: Biology

The bacteria messes with your body chemistry. Your brain, being part of this general biochemistry, is also affected.

“Leaky gut” isn’t a real medical diagnosis, not according to the gastroenterologists that I know, anyhow. It’s mostly a diagnosis that naturopaths and other quacks give to people with depression and other problems. They target people that have felt bad for a long time, and are reaching out for something to help them. These quacks give them a name for why they feel bad, and say they can help them with dietary advice and supplements. It’s basically just a way for them to cash in on the “gut microbiome” craze.

I know of a couple of studies that show people with SIBO have pretty much the same rates of depression and anxiety as anyone else, but I’ve never seen a study showing that SIBO causes depression. The only place I’ve ever seen anyone claiming that SIBO causes depression is on the websites of “alternative” practitioners who are trying to sell magical cures and treatments.

The bad bacteria can send harmful messages and your brain can then send harmful messages back along paths that go between them. That’s extremely simplistic, but you wanted a simple explanation. If you’d like a more advanced understanding I’d recommend looking up journal articles on Google scholar. It isn’t pseudoscience and I suspect those saying it is haven’t researched it. Probiotics help.

It doesn’t. “Leaky gut” and even SIBO unless diagnosed by a doctor with fecal cultures are not real and proven problems. The idea of leaky gut is someone inventing a problem so they can sell you a solution that won’t actually work. They set it up so that you blame yourself for still having issues to try to get you to try a different cure for a made-up disease.

SIBO can be a real thing, but it’s extremely rare and isn’t an *overall* overgrowth. It’s a situation where, usually through antibiotic use, something like c. dificile or other bacteria gains ground that it usually can’t in a healthy system. Your body is always at almost maximum capacity for bacteria, especially in your guts. There is competition for food that keeps the balance between good/bad/neutral. Bringing antibiotics in can override the balance and allow a semi-permanent change in what has the most resources and where it can be. You aren’t suddenly having a huge increase in bacteria, but rather are having a problem with what is in charge.
Treatment is antibiotics and probiotics, and usually takes several months.


But we don’t know if it’s real or not yet.

I would recommend [the psychobiotic revolution]( for an accessible explanation of this topic.