Here at Schreiber Allergy, we are getting many questions and visits related to food intolerance. We hope that this post can answer some common questions regarding the differences between food allergy and food intolerance.
It is true that adverse reactions to foods are very common. But it is important to understand the difference between a true food allergy and food intolerance, also known as food sensitivity.
Food Allergy
An IgE-mediated food allergic reaction involves the immune system. The reaction is immediate (within minutes to a few hours at most) and is reproducible, meaning that every time the immune system is exposed to the offending food, it will react. Symptoms of a food allergic reaction can include itching, rash, hives, swelling, difficulty swallowing, tightness in the throat, difficulty breathing, wheezing, coughing, nausea, stomach aches, vomiting, heart palpitations, feeling faint, and losing consciousness.Unlike an intolerance to food, a food allergy can cause a serious or even life-threatening reaction.
Common food allergens in children include milk, egg, soy, wheat, and peanut. Common food allergens in adults include peanut, tree nuts, fish and shellfish.
The history is the most important part of the evaluation of food allergy. Allergy testing may be indicated when the history suggests a possible food allergy. If the history does not suggest a food allergy, then testing may not be necessary.
Specific tests we perform for true food allergy in the office include skin prick testing, serum specific IgE testing (blood testing) and oral food challenges.
Food Intolerance
A food intolerance response involves only the gastrointestinal (GI) system, aka the digestive system or the gut. It is a non-immunologic response to a food and is not always reproducible. It occurs when you are unable to properly breakdown the food or a part of the food. This could be due to enzyme deficiencies, sensitivity to food additives or reactions to naturally occurring chemicals in foods. Often, people can eat small amounts of the food without causing problems. Symptoms can include bloating, cramping, gas, heartburn, constipation, nausea, vomiting, and diarrhea.
Common food intolerances include dairy (lactose), wheat, gluten, and some fruits and vegetables.
There is no testing available for most food intolerances. A number of companies produce “food intolerance tests” which are now available at pharmacies, health stores, and even online. However, these tests are not based on any scientific evidence, they are not reliable, and are not recommended by the American Academy of Allergy, Asthma and Immunology or the American College of Allergy, Asthma and Immunology.
Here at Schreiber Allergy, we do not perform any food intolerance testing. The best way of diagnosing a food intolerance is to monitor your symptoms and the foods you eat. See what happens when you completely cut out the suspected food for a while, and then reintroduce it into your diet.
If symptoms are happening with many or multiple foods, it likely is not a food intolerance at all. Some conditions can be confused with food intolerance and include chronic infection, irritable bowel syndrome, inflammatory bowel disease, stress, and anxiety.
Some studies show that up to one in three people report having a food allergy. However, only one in 20 actually do. This discrepancy often comes from an incomplete understanding of the differences between food allergy vs. intolerance, or even normal response to some foods. It is crucial to distinguish between food allergy and food intolerance because in general, a food intolerance does not increase risk of progression to anaphylaxis, a potentially severe life-threatening allergic reaction.
Please check out our Schreiber Allergy YouTube channel to watch a short video of Dr. Schreiber discussing the differences between food allergy and food intolerance.
Resources:
- American Academy of Allergy, Asthma and Immunology (AAAAI) – Food Intolerance versus Food Allergy:
- American College of Allergy, Asthma and Immunology (ACAAI) – Food Allergy
- UCLA Department of Allergy and Immunology – Food Allergies
- Nationwide Children’s Hospital – Food Allergy vs. Intolerance: Knowing the Difference