Contributor: Kadakkal Radhakrishnan, MD
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If your little one is suffering from bloating, diarrhea, cramping, pain and constipation, it’s likely that you’ve thought of commonly discussed conditions, such as irritable bowel syndrome (IBS), lactose intolerance and Crohn’s disease.
But your child’s stomach aches and pains might actually be due to fructose, a simple sugar used to sweeten many processed foods and beverages.
Fructose is naturally present in most fruits and some vegetables, but it’s also found in many processed foods and drinks, such as candy, juice, soda and snack foods, making it difficult to avoid.
Dietary fructose intolerance, a genetic metabolic disorder that can be mistaken for many other gastrointestinal disorders, occurs when the intestines cannot properly absorb the fructose sugar.
Diagnosing fructose intolerance
Fructose is absorbed through a specific transporter in the intestinal lining. Some people absorb less than optimal amounts of fructose due to a relative deficiency of this transporter.
When people with this deficiency consume food with a high fructose content, more fructose remains in the bowel opening. This excess fructose is subsequently fermented by the normal gut flora, causing a laxative-like effect and symptoms, such as gas and bloating.
Sometimes, the reduction in fructose transport may be secondary to disorders affecting the inner lining of the bowel, like celiac disease.
Some people are more sensitive to fructose than others, and this suggests that there’s variation in absorption and overall gut sensitivity. Some evidence suggests that patients with irritable bowel syndrome experience more symptoms related to fructose consumption than people without IBS. This also points to possible variation in gut sensitivity in different people.
A good medical history is important in a child with symptoms that point to dietary fructose intolerance, and it’s necessary to assess the overall intake of fructose in his or her diet.
The diagnosis of fructose intolerance can be made by a simple test called a fructose breath test. This test measures the rise in hydrogen in a person’s breath after an oral dose of fructose. It’s important to note that the test needs to be interpreted carefully by a physician in the appropriate clinical context due to the chance of false positives.
What to do if your child is affected
It’s crucial to work with a pediatric dietitian to determine how to effectively cut down and remove fructose-containing foods from your child’s diet.
Foods with higher fructose have to be avoided and then slowly reintroduced in small quantities to determine a child’s level of tolerance.
Foods with higher glucose content in relation to fructose may be better tolerated since glucose can facilitate absorption of fructose and reduce symptoms. For this reason, consuming glucose with fructose-containing foods may help.
Avoid foods that contain fructose, high-fructose corn syrup and sorbitol in the ingredient list. Fruit, fruit juices, powdered sugar, soda, sports drinks, sweetened milk and honey should also be removed from your child’s diet and slowly reintroduced to assess tolerance.
The low FODMAP diet may help some patients. FODMAPs — or fermentable oligosaccharides, disaccharides, monosaccharides and polyols — are short-chain carbohydrates that are poorly absorbed in the small intestine. This means that eliminating such foods may help alleviate some not-so-nice digestive symptoms your child may be experiencing.
There is some suggestion that an enzyme supplement called xylose isomerase could help convert fructose to glucose and may help some patients. However, I do not recommend this, as the efficacy and safety of this product are unclear.
This post is based on one of a series of articles produced by U.S. News & World Report in association with the medical experts at Cleveland Clinic.