Food Intolerance is an adverse reaction to certain types of foods or ingredients contained therein. Unlike food allergy, it does not influence the immune system; nor is it caused by toxic substances as in food poisoning; it is not psychological either.

However this is rather a common ailment which is noticed in a number of people. Usually this malaise is not serious and every one of us has intolerance towards certain form of food or other. However if the range of foods towards which one is intolerant is expansive then food intolerance should receive medical attention.

Causes of Food Intolerance

Enzyme deficiency and adverse reactions to chemicals in foods are the two causes of food intolerance. In the former case, a person lacks certain enzymes necessary to digest a particular type of food. For example, lactase deficient people cannot tolerate cow’s milk, while alcohol dehydrogenase enzyme deficient people feel unwell by drinking even small amounts of alcohol.

In the latter case, people might have adverse reactions to preservatives and additives in foods, and to even normally present ingredients like salicylates. Genetics plays a vital role in food intolerance. Both types of enzyme-deficient intolerance mentioned above are more common among Asians than among Europeans. Age is also a factor in developing intolerance, for example, with milk. Chemical intolerance can occur amongst individuals with or without family histories of allergy. It is also more common among women, and may be due to hormone differences.

Symptoms of Food Intolerance

Nausea, bloating, abdominal pain, diarrhea, headache and dizziness are common symptoms of food intolerance. Some of these symptoms give a false impression of allergy, though they are two very different diseases.

Food intolerance can also produce symptoms of Chronic Fatigue Syndrome, Myalgic Encephalomyletis, Post-viral fatigue Syndrome and leaky gut syndrome. Bizarre Central Nervous system symptoms, unless recognized as food intolerance, can falsely label patients as neurotic or hysterical.

Special cases: lactase and salicylate intolerance

People lacking the enzyme lactase, which is needed to digest milk, develop milk or lactase intolerance. This commonly occurs after the age of 2, since babies have higher levels of lactase. Salicylates, on the other hand, are naturally-occurring chemicals in many foods, including tomatoes, apples, wine, avocado and cheese; salicylate sensitivity is a common form of food intolerance.

Diagnosis of Food Intolerance

Elimination and challenge testing, or removal of the food from the diet and controlled reintroduction are the usual diagnostic methods. Lactose intolerance can however be tested using lactose intolerance test, hydrogen breathing test and stool acidity test.

For other types of intolerance, food elimination diets are designed to exclude potentially harmful food. During the process, care needs to be taken to detect food addiction, masking, withdrawals and further sensitization among patients.

5 days are required to unmask a food/chemical, 7 days during which withdrawal symptoms may occur, and all traces of the food are removed within 2 weeks. If after 6 weeks, symptoms still persist, food intolerance is assumed to be uninvolved.

If symptoms, on the other hand, are reduced or mitigated within 2 weeks or more, challenge testing begins. In this process, selected foods are reintroduced into the diet to identify chemicals that cause food intolerance.

Treatment of Food Intolerance

Avoidance of intolerable foods and re-establishing a level of tolerance are the two methods of treatment. Lists of tolerable foods are commonly available, and tolerance can often be built up by careful food consumption.

However, if a food is excluded from the diet, care must be taken to introduce other foods providing equivalent nutrition. For instance many children are often intolerant towards milk and in such cases milk intake is often stopped. Care however should be taken to ensure that instead of milk the child receives other substitute nutritional elements.