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Sucrose IntoleranceConditions

Sucrose intolerance refers to the body's inability to properly digest sucrose, commonly known as "table sugar." This type of sugar is found not only in cane sugar but also in maple syrup, various fruits, legumes, and some vegetables. A crucial enzyme called "sucrase-isomaltase," located on the surface of small intestine cells, normally breaks down sucrose so it can be absorbed into the bloodstream. When there's not enough of this enzyme, undigested sucrose moves into the colon, where gut bacteria break it down, leading to symptoms like gas, bloating, diarrhea, and discomfort. Formerly considered rare and mainly seen in childhood, sucrose intolerance can affect a larger portion of the population, persisting into adulthood and often being misattributed to other digestive issues like irritable bowel syndrome (IBS). The condition is typically genetic, but it can also result from inflammation or infection of the small intestine, which can be treated to restore normal digestion.


The symptoms of sucrose intolerance can be quite uncomfortable. They include bloating, gas, diarrhea, and general abdominal discomfort. These arise because the undigested sucrose that reaches the colon gets fermented by bacteria, leading to the release of gas. If you experience these symptoms regularly, especially after consuming sugary foods or fruits, sucrose intolerance might be the culprit. It's essential to recognize these signs for accurate diagnosis and appropriate management.


Our dietitians can help determine if you should be tested for sucrose intolerance based on your food habits and symptoms. To confirm the diagnosis, a 13C-sucrose breath test can be conducted, even from the comfort of your home. After consuming a special sucrose solution, you'll breathe into a bag at specific intervals. The laboratory will analyze the air you exhale to measure sucrase-isomaltase enzyme activity. Alternatively, small intestine biopsies can be collected during endoscopy and provide more precise insights into enzyme activity. This method also checks for other digestive enzymes related to lactose and starch digestion. Depending on the situation, the diagnostic approach may vary.


While the sucrase-isomaltase enzyme deficiency can't always be fully corrected, effective management options exist. If an underlying cause is identified, addressing that cause becomes the focus. However, for most cases, managing sucrose intolerance involves a combination of enzyme supplements and dietary adjustments. Prescription enzyme supplements, though requiring refrigeration, can significantly help you tolerate sucrose-containing foods when taken before meals. Yet, for convenience, dietary changes might be necessary on occasions when enzyme supplements aren't accessible. Our GI dietitians are here to guide you through identifying sucrose in foods, reading labels, selecting suitable sweeteners, and making food choices when enzyme supplements aren't an option. Remember, consuming sucrose might be uncomfortable, but it doesn't pose long-term harm to your intestines.