What is SIBO (Small Intestinal Bacterial Overgrowth)

Small intestinal bacterial overgrowth (SIBO) is an excessive bacterial growth in the small intestine and sadly, it is becoming increasingly more common and an issue I treat on a regular basis.

It can be complicated to explain however the small intestine is normally only sparsely populated by bacteria, with small numbers of species such as lactobacilli and enterococci. In some people, there won’t be any bacteria at all in the upper part of the small intestine. SIBO occurs when bacterial populations from lower down the gastrointestinal tract migrate up the gut and colonise the small intestine. The majority of the time, species are not favourable and produce damaging gases responsible for some very obvious gut symptoms.

These microbes feed on carbohydrates in foods and drinks, producing gases including hydrogen, methane and hydrogen sulphide because of this feeding process. The bacteria also produce endotoxins as metabolic waste products, which cause inflammation and damage to the intestinal wall, impairing nutrient absorption.

This additional gas can be the cause of bloating, constipation, diarrhea, slower or faster gut motility and reactions to a range of foods.  Acid reflux and heartburn can also be a consequence.  Another issue that often occurs at the same time is an overgrowth in the colon (large intestine).