Medically reviewed by Onikepe Adegbola, MD, PhD
Irritable bowel syndrome (IBS) patients often experience gastrointestinal symptoms, including bloating, abdominal pain, and constipation or diarrhea. However, these uncomfortable IBS symptoms often overlap with those of sucrase-isomaltase gene deficiency.
Researchers have discovered that many individuals who have been diagnosed with IBS also have a variation or defect in a gene for sucrase-isomaltase. Sucrase-isomaltase is an enzyme for digesting certain sugars, including starch and sucrose (table sugar).
Researchers from in Melbourne, Australia published the study, “,” published in the journal .
One of the main concerns for medical professionals is the overlap between the symptoms and presentation of sucrase-isomaltase gene deficiency and that of IBS. However, besides genetic markers, the primary differentiation tends to be that individuals with sucrase-isomaltase gene deficiency do not respond well to the low FODMAP diet and are often even worsened by it.
The low FODMAP diet does not reduce starch and sucrose consumption, which is the dietary treatment for sucrase-isomaltase gene deficiency. However, the study shows that starch and sucrose elimination is used for a 50% of symptom reduction for those with sucrase-isomaltase gene deficiency. Moreover, the enzyme sacrosidase causes symptoms to resolve completely.
Markers of a sucrase-isomaltase gene deficiency, as opposed to IBS, are developed in childhood and a poor response to the low FODMAP diet.
This study suggests that if a sucrase-isomaltase gene deficiency is suspected in someone with IBS symptoms, further testing and evaluation are needed to determine a more appropriate course of treatment. Anyone who suspects they may have this gene deficiency should consult with their doctor to discuss the best possible treatment plan for them.
Foley, A., Halmos, E. P., Husein, D. M., Fehily, S. R., Löscher, B.-S., Franke, A., Naim, H. Y., Gibson, P. R., & D’Amato, M. (2021). Adult sucrase-isomaltase deficiency masquerading as IBS. Gut, 71(6), 1237–1238. https://doi.org/10.1136/gutjnl-2021-326153