What are the known causes to cause leaky gut syndrome?

See below: Leaky gut syndrome is not an established medical diagnosis. If your have gastrointestinal issues i recommend being evaluated by your primary md or gastroenterologist.

Be discerning: "Leaky gut syndrome" is a "pop" / "fad" diagnosis based on some work in the 1980's suggesting that some people have extra-permeable intestinal linings. Supposedly this causes most / all disease. The simple test using the ability to absorb sucrose molecules intact could show that it's real; the burden of proof remains on believers. If you decide you have this, you'll never fell well again.