Food Sensitivity and Food Allergy: What's the Difference?

Child drinking mild

Food allergy and sensitivity are increasingly common topics. You may find information on social media, websites, or from your neighbors, and it can be difficult to know what to do.

First, let’s talk about the difference between a food allergy and food intolerance. A food allergy is your body’s immune system reacting to a certain food. Food allergy reactions can be serious and life-threatening as the allergic reaction moves from one organ system to another. On the other hand, food intolerance may be the result of your body’s inability to process (read: break down) food. There are some well-defined intolerances, such as lactose intolerance, where the gut is not able to metabolize the sugar in cow’s milk leading to abdominal pain and other gastrointestinal symptoms. In some cases, people suffering from food intolerance may be able to eat a limited amount of the offending food without experiencing symptoms.

If you have been reading about food testing, you may have read about two types of tests: IgE and IgG.

IgE

Allergen immunoglobulin E (IgE) is a type of antibody produced by people whose immune systems mistake a food as a hostile invader—the body produces the antibodies to repel the invaders. IgG is the antibody that is most common in the immune system and is part of the immune system that helps to prevent infections. It is found in all body fluids and protects against bacterial and viral infections.

The food testing offered by board-certified allergists looks at specific IgE to foods and is most helpful in evaluating symptoms distinctly related to foods. A child who has hives and vomiting after eating peanuts will likely have positive peanut-specific IgE. IgE can be detected with skin testing and blood testing. In some cases, IgE to foods can play a role in stomach pain or skin rashes. Some patients may feel better when they remove positive foods from their diet. Talking with your allergist about what information skin testing provides is important, as is the allergist’s interpretation of the results after the test.

IgG

Some labs offer tests based on blood samples that look at IgG. There is not good skin testing for IgG to foods. According to the American Academy of Allergy, Asthma, and Immunology (AAAAI), the presence of IgG to foods to foods is likely a normal response of the immune system to exposure to food. Insurance companies do not cover food IgG testing because it is not validated. In fact, IgG food panel testing has not been scientifically proven to identify foods that cause symptoms as of the date of this blog post. Indeed, there is no single test that will tell a patient what foods to avoid in order to feel better. Due to the lack of evidence to support the testing for IgG to foods, the AAAAI, the Canadian Society of Allergy and Clinical Immunology, and the European Academy of Allergy and Clinical Immunology all have recommended against using IgG testing to diagnose food allergies or intolerances/sensitivities. In addition, IgG testing does not give clear guidance on what exactly the results mean or how to interpret them in the clinical setting.

Want To Learn More?

Dr. von Elten is happy to evaluate your symptoms and work with you to determine what testing may help determine the underlying causes of symptoms. The interpretation is as important as the results of the testing. Though there is a lot of testing out there, it is important to have a board-certified allergist help to formulate the right plan for you.