The science explained simply

In a healthy gut, the lining of the small intestine is tightly sealed, allowing nutrients to pass through while keeping toxins, bacteria, and food particles out of the bloodstream.

In SIBO, excessive bacteria in the small intestine:

• Produce large amounts of gas and inflammatory by-products

• Disrupt the tight junctions between intestinal cells

• Increase intestinal permeability

This process allows bacterial toxins and partially digested food particles to “leak” into the bloodstream, triggering an immune response.

A simple way to think about it:

The small intestine is not designed to hold large amounts of gas. In SIBO, constant gas production stretches and irritates the intestinal lining, creating microscopic gaps in the gut wall. Through these gaps, unwanted substances can escape into circulation.

Each time this happens—often after eating—the immune system reacts as if it is under attack. Over time, this repeated immune activation leads to persistent inflammation, contributing to widespread symptoms throughout the body.