To Your Good Health: Fructose intolerance is rarely diagnosed

What can you tell me about fructose intolerance and/or malabsorption? Is there a genetic predisposition to this? Can it develop later in life? What are the symptoms, and how is it diagnosed? What type of doctor can best make a diagnosis? I’ve read conflicting reports online regarding the breath analysis test. Can it be treated, or must one eliminate foods containing fructose completely from one’s diet? My father was diagnosed with some sort of fructose problem years ago. I have no other information about his condition as he has passed away. I have developed some intestinal issues over the past year and have noticed I frequently experience stomach cramps after eating grapes and green apples, specifically. I am a vegetarian, and my diet consists of lots of fruits and vegetables. I’m wondering if I may have an issue with fructose. I hope not! What are your thoughts?

Fructose intolerance is common, but it is seldom diagnosed. One cause, hereditary fructose intolerance, is a genetic disorder that can cause serious symptoms in infants and children, but it is usually mild in adults.

The symptoms of fructose intolerance are very similar to another sugar intolerance — lactose, the sugar in milk. Many people cannot tolerate lactose and if they eat too much of it will have cramping and diarrhea. Unlike lactose intolerance, which has a simple diagnostic breath test, there is no commonly available test for fructose intolerance.

Fructose is a simple sugar, called a monosaccharide, and is found in many fruits, especially apples, pears, cherries and dates. Fructose is also found in honey and is part of the disaccharide sucrose, or table sugar, where it is combined with glucose.

What is fascinating yet poorly understood is that when fructose is consumed with glucose, it is absorbed better by people with fructose intolerance. Therefore, the goal in someone with inability to absorb fructose is to reduce or avoid fructose by itself.

That means reducing foods and beverages sweetened with high-fructose corn syrup, which is present in many products; eating high-fructose fruits only with meals; and reducing honey intake.

Sorbitol, a sugar alcohol used as a sweetener in “diet” or “sugarless” foods, tends to worsen fructose intolerance and should be avoided.

A vegetarian diet is very healthy for most people, and you shouldn’t have to give up your fruits. Just following some simple rules should reduce or eliminate your symptoms.

Burning Mouth Syndrome

A recent column on burning mouth syndrome generated a lot of letters, including several from physicians and dentists. The advice I heard over and over is that some dental products seem to worsen the symptoms, and changing toothpaste or dental rinse can help with symptoms.

However, the culprit was not consistent. Some writers told me it was mint, others said cinnamon, while others thought it was the sodium lauryl sulfate that is in many toothpastes. Baking soda, or toothpastes based on them, seemed to be well-tolerated for many.

Other irritants that made symptoms worse included spicy foods, carbonated beverages, caffeine and acidic foods, like citrus or tomato.

Other advice I heard was soaking the tongue in a solution of Splenda and water. Others recommended biotin supplements.

The sheer number of letters leads me to suspect that this is a more common problem than I would have thought. Very few of my own patients have ever asked me about this in my practice.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@ med.cornell.edu. © 2020 North America Synd., Inc.