No clear population studies have been done to show the incidence of fructose malabsorption in humans. However, several small studies with convenience samples give us clues. The studies involve patients who come to a clinic with gastrointestinal distress. Ethnic origin does not seem to be associated with fructose malabsorption. Females seem more likely than males to have the disorder.
Fructose malabsorption appears to decrease with advancing age.
In the study patients and controls were challenged with an oral load of 25 g of fructose. This suggests that fructose malabsorption might be fairly common, but that the majority of people show no symptoms. If the amount of fructose in one to two cans of regular soft drink is enough to cause symptoms in some adults who are fructose intolerant, then children who are fructose malabsorbers and have much smaller body size, might experience the symptoms of irritable bowel syndrome due to excessive use of soft drinks. Naturally there are many other causes for gas, bloating, cramps, and diarrhea. Any child with such symptoms should have a complete evaluation by a physician and not rely on parental diagnoses.