Fructose is a natural component to many sweet-tasting foods, such as honey. A monosaccharide---or simple sugar---fructose can be used to make sucrose, more commonly known as table sugar. Fructose also can be mixed with glucose to create high-fructose corn syrup, which is used to make many packaged desserts. Due to a genetic predisposition, some people are not able to digest fructose, which may result in problematic symptoms and even liver and kidney damage in severe cases.
Significance
Two conditions are related to difficulty digesting or absorbing fructose. The first and more serious is a hereditary fructose intolerance. Although very uncommon, this genetic disorder involves the lack of a digestive enzyme that can break down fructose in the body, according to the Mayo Clinic. This condition often is diagnosed in young children and is considered very serious because it can cause damage to the liver and kidneys.
The other condition is fructose malabsorption, which occurs when the body cannot fully digest fructose. Side effects of this condition include stomach pain, gas, constipation and diarrhea.
Foods to Avoid
If you have been diagnosed with fructose-digestion disorders, avoid foods that contain fructose, sucrose and sorbitol. Examples include confectioner's sugar; fruit juice; fruits; honey; sodas; sports drinks; milk that has been sweetened; flavored waters; and anything that contains high-fructose corn syrup.
Time Frame
When fructose is consumed solely in the form of fructose (such as in an apple or other fruit or vegetable), it is not digested at all, but instead is broken down thanks to enzymes existing in the digestive tract. However, those with fructose intolerance are not able to break down the fructose in the way the body is accustomed. In those with fructose malabsorption, fructose is not completely absorbed in the small intestine; if fructose travels to the lower intestine, it can bind with the natural flora in the body to cause gastrointestinal discomfort such as gas, bloating and diarrhea.
Effects
Initial symptoms of fructose intolerance closely resemble lactose intolerance: diarrhea, flatulence or gastrointestinal distress are all associated with fructose problems. Other, more long-term symptoms can occur as well. These include anemia, problem skin appearance, poor nails and hair or osteoporosis, according to Mayo Clinic.
Prevention/Solution
There are a number of tests available to determine hereditary fructose intolerance and malabsorption; your doctor can arrange for them if you are concerned that you have one of these conditions. You may also use a fructose-avoidance diet to test for improvement of symptoms. If you avoid foods containing fructose for three days and experience a reduction in symptoms, you may be fructose-sensitive. If this diagnosis occurs, continue an avoidance diet, which involves carefully reading food labels and resisting any foods that contain fructose or one of its forms.
