Following an illuminating study conducted by Ruchi S. Gupta and her colleagues Christopher M. Warren, et al, it is clear that most Americans don’t understand the difference between a food allergy and a food intolerance. The study found that in the U.S. 20% of adults claim to have a food allergy, but when evaluated by a medical doctor only 10% have symptoms consistent with a true allergy.
What is a food allergy? What makes it unique?
Food allergies are an immune system response to food. When the body mistakes a food as harmful, it produces a defense system (in the form of antibodies) to fight against it. These antibodies in the immune system – called immunoglobulin E (IgE), found in the lungs, skin and mucous membranes – release a chemical that sets off a chain reaction of the vascular, respiratory, and cardiac systems.
Food allergic reactions can vary from hives, swelling of the mouth, lips and face, and vomiting to respiratory issues (such as wheezing), drop in blood pressure, fainting, and cardiac arrest. Anaphylaxis is a very serious and potentially fatal condition that is characterized by a sudden drop in blood pressure, loss of consciousness and body system failure. Epinephrine (administered by an auto-injector) is the only medication that can slow or stop anaphylaxis.
The most common foods that cause a food allergic reaction are: peanuts, tree nuts (such as walnuts, pistachios, pecans, etc), dairy, eggs, wheat, soy, fin fish (salmon, tuna, etc), and shellfish. But almost any food can cause an allergic reaction.
What is a food intolerance? How does it differ from a food allergy?
Food intolerances also make people feel discomfort. However, this discomfort is not life-threatening. Food intolerances are a digestive response that occur when food irritates the digestive system or makes it difficult for a person to break down the food.
Symptoms of a food intolerance can include bloating, gas, nausea, stomach discomfort/pain, vomiting, diarrhea, heartburn, headaches, and irritability. Dairy, or lactose intolerance, is the most common trigger.
What are some other differences?
Food allergic reactions can occur with even the smallest amount of food ingested. In addition to the range of major symptoms when ingested, it can also cause a skin reaction just upon contact. A food allergy is a reaction to the protein contained in a food (such as gluten with a wheat allergy).
With food intolerances, amount of food consumed matters. The more food consumed, the worse the digestive reaction. Food intolerances occur because the body cannot break down the sugar in a given food (like lactose in milk).
Food allergies are diagnosed in several ways. The golden standard is an oral food challenge – where a patient eats their suspected allergen under medical supervision to note the reaction. Patients may take an IgE blood test or be asked to take a skin prick test to diagnose and monitor food allergy.
When a food intolerance is suspected, patients are often asked to keep a food journal or diary in which they note the foods they ate as well as the symptoms they experience. Patients may also be asked to eliminate a particular food from their diet and note symptoms for a period of time.
In both cases, a doctor will help give an official diagnosis and guide the patient through any changes that need to be made to their lifestyle. Those with food allergies will also discuss issues like cross-contamination, emergency action plans, and epinephrine. Those with food intolerances may talk about medications that can help to ease symptoms. Avoidance of problem foods will be suggested for food allergies as well as food intolerances.
Knowing the difference between a life-threatening food allergy and an uncomfortable food intolerance will help keep you safe, make appropriate lifestyle changes and get you the relief you need sooner.