Food intolerance occurs when an individual has an adverse reaction to certain food or foods. Food intolerance is differentiated from food allergy because the former denotes a sensitivity, the latter a reaction of the immune system. Where a food allergy can be extremely dangerous, at times resulting in a life-threatening anaphylactic response, a food intolerance causes localized problems. Also, while food allergies often come on suddenly, may be increasingly severe, and, once established, can be set off by a very small quantity of the offending food stuff, food sensitivities usually come about gradually and cause milder symptoms. In addition, individuals with food sensitivities are often able to eat small quantities of the food in question without difficulty.
Causes of Food Intolerance
There seem to be both genetic and environmental factors at play in the development of food intolerance. Since being intolerant to particular foods is more common in certain ethnic groups, there is clearly a genetic component to the condition. Reasons for food intolerance have not been wholly deciphered, however, though the following causes have been isolated:
- Lack of a particular enzyme, as in lactose intolerance
- Inborn metabolic disorder, like diabetes
- Gastrointestinal abnormalities resulting in malabsorption
- Certain diseases, like Celiac disease (gluten intolerance)
- Sensitivity to food additives, such as sulfites (often found in dried fruit)
- Psychological stress associated with intake of a particular food
The causes of food intolerance may be difficult to assess, particularly if they have a psychological root. In such cases, when the affecting food is served in a disguised fashion it may be well-tolerated.
Symptoms of Food Intolerance
There are many and various symptoms of food intolerance. Some of the symptoms of food intolerance are the same as those of food allergies, except that food intolerance symptoms do not ever become life-threatening. Symptoms of food intolerance include:
- Nausea or vomiting
- Stomach pain
- Diarrhea or anal irritation
- Gas, cramps, or bloating
- Acid reflux (heartburn)
- Headaches
- Irritability or nervousness
Food intolerance symptoms are most often digestive, but such sensitivities may also result in skin rash, eczema, mild hives, nasal congestion, throat irritation, sneezing and itchy, watery eyes.
Foods That Commonly Cause Problems
In children, common causes of food intolerance are milk, eggs and gluten. Possible culprits for people of all ages are:
- Milk and dairy products
- Eggs
- Peanuts and tree nuts (walnuts, almonds, pecans)
- Strawberries, tomatoes, bananas, pineapples, citrus fruits
- Soy and soy products
- Gluten or wheat
- Shellfish
- Wine
- Chocolate, coffee, tea, cola
- Foods that contain sulfites or other additives, like hotdogs
An obvious solution to food intolerance is avoiding the food with the negative effect. This is not always easy, however, since many foods may be found in unlikely places. Nuts, for example may be used in cakes and cookies, or soybean oil hidden in processed salad dressing. Individuals with food intolerances, and parents of children with such limitations, have to be careful to read labels.
Diagnosis of Food Intolerance
It is sometimes difficult to definitively diagnosis food intolerance because many disease conditions, such as irritable bowel syndrome, may present with similar symptoms. The patient may be asked to keep a diary of all foods eaten and to note any negative reactions.
Allergy testing may also be administered to help diagnose food intolerance. This testing may be administered in several different ways, including breath tests for lactose intolerance, patch tests on the skin, and blood tests. Often, an exclusion diet, in which suspected foods are eliminated one by one from the patient's diet, provides clear evidence of precisely which food is causing the problem.
Treatment of Food Intolerance
Frequently, all that is necessary to treat food intolerance is detecting the food with the negative effect and avoiding it. In cases where the food is extremely difficult to avoid, like milk and dairy products, patients may be able to take supplemental enzymes, like lactose (Lactaid) in order to increase their ability to digest the troublesome food and food products that include it in their contents.