Fruit juice intolerance should be checked by a doctor

Q. Fruit juices give me a stomach ache. Do you think I'm allergic to them?

I never diagnose because I'm not a physician; I'm just a journalist. If you have a problem digesting fruit juices and this is getting in your way, you should get a checkup.

Meanwhile, you might want to keep a diary of the food you eat; this will isolate foods that are giving you digestion problems. The intensity of your reaction can help determine whether you are allergic to certain foods or are suffering from a food intolerance.

A food allergy is an abnormal response to a food triggered by the body’s immune system. An allergic reaction to food occurs quickly – sometimes within only a few minutes. Reactions include oral itching, vomiting, diarrhea and abdominal pain. You may have a drop in blood pressure, asthma, and skin reactions such as hives or eczema. Allergic reactions to food can cause serious illness and, in some cases, death.

Sometimes, a reaction to food is not an allergy but a “food intolerance.” Food intolerance is more common than food allergy. The immune system does not cause the symptoms of food intolerance, though these symptoms can look and feel like those of food allergy.

Many people think they have food allergies. However, most symptoms are caused by intolerances to foods such as wheat and other grains, sugar found in fruits and honey, dairy products, and corn products.

If fruit juices are giving you a stomach ache, there is a possibility that you have fructose intolerance.

Fructose is a sugar in fruits, honey and some syrups. Fructose is also a basic component in table sugar (sucrose), and it's used to sweeten many processed foods and beverages.

In addition, sorbitol – a sugar alcohol – is converted to fructose during normal digestion. Sorbitol is a sugar substitute often used in diet drinks, ice cream, mints, cough syrups, and sugar-free chewing gum.

You should avoid foods with fructose in them. In addition to fruits, honey, syrups and table sugar, you should watch out for high-fructose corn syrup, powdered sugar, regular sodas, flavored water, sports drinks and sweetened milk. Read food labels carefully to avoid fructose.

The term fructose intolerance covers two conditions: hereditary fructose intolerance and fructose malabsorption. People with hereditary fructose intolerance, a rare genetic disorder, lack an enzyme that breaks down fructose. This a serious disorder that can lead to liver and kidney damage.

Those who have fructose malabsorption have difficulty digesting fructose. This is a less serious disorder because it doesn't cause organ damage. But it can cause abdominal pain, gas, bloating and diarrhea. Either condition should be confirmed by a doctor.