Small Intestinal Fungal Overgrowth (SIFO) is characterized by high numbers of fungi in the small intestine, while Small Intestinal Bacterial Overgrowth (SIBO) is caused by elevated numbers of bacteria. Much more is known about bacterial overgrowth, but it’s still poorly understood. It is thought that microbial overgrowth could play a role in unexplained GI symptoms such as gas, bloating, and abdominal pain.
Recent studies have used more accurate sampling and quantification methods to detect Candida and other forms of fungi in the small intestine. Though sampling this way can accurately detect intestinal overgrowth of bacteria and fungi, these studies found that the rates of unexplained GI symptoms were similar in participants regardless of their fungal colonization. In a study that sampled the gastric (stomach) mucosa of people with dyspepsia (indigestion) or ulcer complaints, Candida was present in approximately 27% of the participants (with no control samples for comparison). A follow-up study compared participants with and without SIFO, and found no differences in the severity of the participants’ GI symptoms. In that study, 25% of the participants with unexplained digestive complaints also had SIFO.
Though prescription antacid medications and altered gut motility (organized muscular contractions) may increase the risk of developing SIBO, they aren’t associated with SIFO.[1]