Food Intolerance

By-Meena Ganagani,Practicing Clinical Nutritionist,Mumbai.

What is a Food Intolerance?

A food intolerance, or a food sensitivity occurs when a person has difficulty digesting a particular food. This can lead to symptoms such as intestinal gas, abdominal pain or diarrhea.

A food intolerance is sometimes confused with or mislabeled as a food allergy.  Food intolerances involve the digestive system. Food allergies involve the immune system. (1)

What are the symptoms of food intolerance?

In general, people who have a food intolerance tend to experience:

  • Tummy pain, bloating, wind and/or diarrhea
  • Skin rashes and itching

These symptoms usually happen a few hours after eating the food. (2)

What causes food intolerances?

There are many factors that may contribute to food intolerance. In some cases — as with lactose intolerance — the person lacks the chemicals, called enzymes, necessary to properly digest certain proteins found in food. Also common are intolerances to some chemical ingredients added to food to provide color, enhance taste and protect against the growth of bacteria. These ingredients include various dyes and monosodium glutamate (MSG), a flavor enhancer.

Substances called sulfites, which may occur naturally — as in red wines — or may be added to prevent the growth of mold, also are a source of intolerance for some people. The Food and Drug Administration has banned the use of spray-on sulfates to preserve fruits and vegetables, but sulfates are still found naturally in some foods. Salicylates are a group of plant chemicals found naturally in many fruits, vegetables, nuts, coffee, juices, beer and wine. Aspirin also is a compound of the salicylate family. Foods containing salicylates may trigger symptoms in people who are sensitive to aspirin. Any food consumed in excessive quantities can cause digestive symptoms. (3)

What is the difference between a food intolerance and a food allergy?

Physical reactions to certain foods are common, but most are caused by a food intolerance rather than a food allergy. A food intolerance can cause some of the same signs and symptoms as a food allergy, so people often confuse the two.

A true food allergy causes an immune system reaction that affects numerous organs in the body. It can cause a range of symptoms. In some cases, an allergic food reaction can be severe or life-threatening. In contrast, food intolerance symptoms are generally less serious and often limited to digestive problems.

If you have a food intolerance, you may be able to eat small amounts of the offending food without trouble. You may also be able to prevent a reaction. For example, if you have lactose intolerance, you may be able to drink lactose-free milk or take lactase enzyme pills (Lactaid) to aid digestion. (4)

Some common types of food intolerance are:

  • Lactose
  • Wheat
  • Gluten
  • Caffeine
  • Histamine, present in mushrooms, pickles, and cured food
  • Additives such as artificial sweetners, coloring, or other flavorings

Some people experience a reaction after eating bread, but this does not necessarily indicate a gluten intolerance. Anyone who suspects they may have a gluten intolerance should see a doctor before giving up gluten, as cereals can be an important source of various nutrients.(5)

Finding food intolerance

Your physician can order a blood test to find what’s causing your symptoms. More often, your doctor will recommend an elimination diet, in which you stop eating one or more potential problem foods for several weeks and gradually reintroduce them one at a time. As part of this process you should keep a food journal to document what you eat and how it affects you.

Your doctor or dietitian may recommend certain digestive aids or alternatives that help you avoid GI symptoms — such as lactose-free dairy products, milk alternatives (like soy milk) or lactase supplements that can help you tolerate dairy.(6)


If you have troublesome reactions to certain foods, it’s important to determine whether the problem is an allergy, celiac disease, or an EGID. If you’re diagnosed with any of these conditions, you must avoid the food trigger or risk anaphylaxis (due to food allergy) or gastrointestinal damage (due to celiac disease or EGIDs). Otherwise, you are free to experiment with dietary changes and other remedies for symptom relief. (7)



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