Fructose intolerance can be deadly

Updated 5/9/2011 6:07 AM

Q. Do you have any information on fructose intolerance? I have been able to find only one book related to the problem. Thank you.

A. Fructose intolerance, commonly known as hereditary fructose intolerance, is a genetic disorder in which the body is unable to break down fructose and some other sugars. It is known as an autosomal recessive disorder, which means that in order to be affected, each parent must have the mutation and pass it on to the child. If only one copy is passed on, the child will be a carrier but will not be affected.

This abnormal gene results in the body missing the enzyme fructose-1-phosphate aldolase, which is responsible for changing glycogen into glucose, which the body uses for energy. Without it, fructose-1-phosphate will build up in the small intestine, liver and kidneys. Following ingestion of fructose, sucrose and sorbitol (a sugar alcohol), the body's blood-glucose levels will drop, causing hypoglycemia. Severe abdominal pain and vomiting may also occur.

Other symptoms include excessive sleepiness, jaundice, irritability, convulsions and more. Sufferers develop a distaste for sweet foods. Liver and kidney damage can occur, and may result in organ failure or death, so strict avoidance of all foods and drinks containing fructose and other sugars metabolized by fructose-1-phosphate aldolase is vital.

Fructose intolerance can sometimes be confused with fructose malabsorption, which is not life threatening but is more common. Fructose malabsorption can cause abdominal pain, bloating, gas and diarrhea but does not result in the liver or kidney damage. However, treatment for both conditions is the same.

The most important aspect of management is avoidance of all sources of fructose, sucrose and sorbitol, including fruits, fruit juices, table sugar, sodas, powdered sugar, sports drinks, honey, high-fructose corn syrup and a great deal more. This can be very difficult. Consulting a registered dietitian and reading labels meticulously will be highly beneficial. The dietitian can help you avoid fructose and maintain a balanced, healthful diet.

Boston University has an entire lab dedicated to the research of HFI and aldolase. It offers information about the condition, diagnosis, treatment, HFI-specific diets and research. There is also a support group, but it only accepts patients with medical-record confirmation of diagnosis. They say this is because while other support groups exist, many contain information for sufferers of fructose malabsorption, benign sugar intolerance and more that may not be applicable to HFI.

Q. Do you know of a cure for Fordyce spots? Do you think laser treatments help? Have you heard of tretinoin cream as a cure? If you have any information on this skin disease, please help.

A. Let me start by saying Fordyce spots are not a skin disease. They are normal. They are large, superficial, oil-producing glands found on mucosal surfaces, most commonly found at the border of the corners of the lips and in the mouth at the back inner cheeks. They do not produce symptoms.

Treatment is usually not necessary because the spots are normal. Treatment (with mild topical steroids) may be recommended in cases when itching and irritation are present, which is typically the result of inappropriate treatment. You can't cure something that isn't a disease. If you are truly concerned, speak with a dermatologist, who will, in all likelihood, confirm what I have said.

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