Fructose is a sugar found naturally in fruits and vegetables. Those with a fructose intolerance have trouble digesting the sugar, leading to symptoms like bloating, flatulence, diarrhea and abdominal pain.
There are two types of fructose intolerance:
It is possible to have an HFI even if neither parent suffers from the condition. However, the condition is usually apparent in infancy, once the baby starts eating fruits.
Fructose intolerance symptoms are similar to those of celiac disease, so if you continue to experience gastrointestinal symptoms on the gluten-free diet, you may want to speak to your doctor about DFI, a fairly common condition.
The main study linking the two conditions is from 2006, which found celiac disease in 10% of those with hereditary fructose intolerance. This is much higher than the ~1% of the general population that develops celiac disease. A case study from 2012 suggested that an HFI may have been the reason a patient with celiac disease was non-responsive to the gluten-free diet.
More research is needed on the possible connection between these two conditions.
Like celiac disease, both DFI and HFI are treated with diet. Those with fructose intolerance must avoid foods high in fructose, primarily sweeteners like honey, molasses, coconut sugar, brown sugar, agave syrup and high-fructose corn syrup. Other foods to avoid include fruit juices, apples, pears and watermelon.
Glucose injections can be used to treat episodes of severely low blood sugar (hypoglycemia attacks).