Food Allergy Patient Information Fact Sheet

What is the difference between a food allergy and food intolerance?
Food intolerance is the general term used to describe a range of adverse responses to food, including allergic reactions, adverse reactions resulting from enzyme deficiencies, pharmacological reactions, and other nondefined responses. An allergic reaction to a food can be described as an inappropriate reaction by the body’s immune system to the ingestion of a food.

Allergic reactions to foods vary in severity and can be potentially fatal. Any food has the potential to cause an adverse reaction. Foods that commonly induce adverse reactions include milk, gluten containing cereals, nuts, peanuts, eggs, and shellfish.

Most people can eat a very wide range of foods without any problems although they may have likes or dislikes that influence what they choose. However, some people react badly to certain everyday foods and eating them may cause uncomfortable symptoms or, in rare cases, a severe illness. But most unpleasant reactions are not true allergies. Food intolerances may cause uncomfortable symptoms but only true allergies involve the immune system. It is important that people who think they suffer from a food intolerance do not change their diet dramatically so that it becomes unbalanced. They should take advice from a dietitian or doctor to be sure that they really do have a problem and take care to ensure that their diet contains a wide variety of foods to provide all the nutrients normally provided by the foods they cannot eat.

What is food intolerance?
Food intolerance is the general term used to describe a range of adverse responses to food, including allergic reactions (eg, peanut allergy or celiac disease), adverse reactions resulting from enzyme deficiencies (eg, lactose intolerance or hereditary fructose intolerance), pharmacological reactions (eg, caffeine sensitivity), and other nondefined responses. Food intolerance does not include food poisoning from bacteria and viruses, molds, chemicals, toxins and irritants in foods, nor does it include food aversion (dislike and subsequent avoidance of various foods). Food intolerance reactions are usually reproducible adverse responses to a specific food or food ingredient, which can occur whether or not the person realizes they have eaten the food.