However, these terms are not mutually interchangeable, as they denote different health conditions. Knowing the difference is important, as the symptoms stemming from those health conditions can range from uncomfortable to life-threatening.
What is the difference?
The easiest way to differentiate between a food allergy, food intolerance, and food sensitivity is looking at the body’s response to the ingested food.
When a patient suffers from a food allergy, the reaction of the body is caused by the immune system. Symptoms include swelling, itching, hives, dizziness, and anaphylaxis. In food allergies, not even small quantities can be tolerated without triggering a reaction. About 20% of people with food allergies experience severe reactions after ingesting trigger foods.
If you suspect you have a food allergy, consider allergy testing and consulting an allergy specialist for a final diagnosis and subsequent treatment. A true food allergy is detected by screening a patient’s blood for elevated levels of IgE antibodies towards certain allergen sources.
The National Institute of Allergy and Infectious Diseases (NIAID) states that around 5% of children and 4% of adults suffer from a true food allergy.
Food intolerance vs. food allergy
Food intolerance is a tricky term, as it can refer to reactions caused by the immune system. At the same time, it also refers to reactions triggered by certain chemicals or additives in food products, or through a lack of enzymes (the most common reason).
The most prominent example for a food intolerance caused by a lack of enzymes is lactose intolerance. With age, a person’s intestines produce less lactase, the enzyme needed to process the type of sugar in dairy products. Research has found that only about 35% people worldwide can digest lactose well after the age of seven or eight. Typical lactose intolerance symptoms include flatulence and diarrhea.
Similarly, histamine intolerant people do not have enough of the enzyme diaminoxidase. This enzyme is needed to properly digest foods rich in histamine (e.g., red wine, cheese, tuna). Some foods are not rich in histamine but can cause the release of histamine in the body, for example citrus fruit, bananas, tomatoes, and chocolate. Typical symptoms for histamine intolerance include migraines, vertigo, gastrointestinal issues, rhinitis, depression, and irritated and red skin.
Food intolerances caused by the immune system can be tested by screening a patient’s blood for elevated levels of IgG antibodies towards certain foods. Common trigger foods include grains containing gluten, caffeine, processed meats, dried fruits, pickled foods, canned vegetables, and high-fructose foods like honey and fruit. If you suspect you have a food intolerance caused by a reaction of your immune system, consider food intolerance testing and consulting a nutritionist for an individual diet plan.
Food sensitivity vs. food allergy
As opposed to a food allergy, the digestive system triggers food sensitivity reactions. Symptoms differ from allergic symptoms as they include gas, bloating, constipation, stomach cramps, diarrhea, and nausea. Food sensitive patients usually tolerate small quantities of a specific food without experiencing adverse reactions.
Food sensitivities can change over time because the body’s gut microbiome is continually changing. If you suspect suffering from a food sensitivity, a so-called elimination diet guided by a nutritionist or physician can help you to figure out what foods you react negatively to.
Another related condition is Celiac’s disease, which is an autoimmune condition affecting about 1% of the Western population. Patients suffering from Celiac’s cannot ingest gluten, because it initiates an inflammatory reaction in the bowels. This can cause diarrhea, weight loss, and malnutrition. Celiac’s disease is not a true food allergy. Despite being very uncomfortable for the patient, it does not cause immediate life-threatening symptoms like a food allergy can.