Food Allergies, Intolerances, and Sensitivities

By Lizzie Streit, MS, RDN, LD 

Feeling sick or having an unpleasant reaction after eating a certain food can indicate a food allergy, intolerance, or sensitivity. The level of severity of these reactions varies, and some can even be life-threatening. 

Understanding the differences between these three kinds of reactions is important for knowing how to address and prevent them. This article discusses food allergies and how they compare to intolerances and sensitivities. 

Definitions, Signs, and Symptoms 

A food allergy is characterized by an allergic reaction that happens after eating a certain food, as a result of the body attacking proteins in that food. Signs and symptoms typically develop within minutes and may include difficulty breathing, itchy mouth, hives, wheezing or coughing, dizziness, vomiting, and/or diarrhea. Depending on the severity, food allergies can be life-threatening and may need to be treated with epinephrine to prevent anaphylactic shock.  

The most common food allergens include peanuts, tree nuts, fish, shellfish, wheat, soy, milk, sesame, and eggs. Celiac disease, an autoimmune disease defined by an allergy to gluten (the protein found in wheat), is often grouped with food allergies. However, it does not cause life-threatening reactions. Still, eating gluten with celiac disease has many negative effects, including poor nutrient absorption and gastrointestinal effects. 

Food allergies often develop in childhood, but they can happen for the first time during adulthood too (especially shellfish allergies). Food allergies are on the rise in the United States, with some estimates suggesting that they increased by 50 percent in children from the late 1990s through early 2000s.  

Intolerances, on the other hand, occur as a result of not having a certain enzyme or other compound necessary for digesting a food. Lactose intolerance, one of the most well-known food intolerances, happens when a person does not make enough of the enzyme lactase that’s needed for processing the sugar in milk. Symptoms of this intolerance include stomach upset, cramps, diarrhea, and bloating after consuming milk and dairy products. 

Finally, food sensitivities are unpleasant reactions that happen after eating certain foods. They may cause bloating, digestive discomfort, rashes, fatigue, or joint pain. They are not considered an official diagnosis in the same way as a true food allergy or intolerance but are thought to happen due to an immune system reaction triggered by eating certain foods. For example, having a negative reaction after eating foods with gluten is often referred to as gluten sensitivity, which is different from a true wheat allergy or celiac disease. 

Addressing Food Reactions 

If you have been diagnosed with a food allergy, it is very important to avoid the problematic food at all costs. It’s helpful to read food labels and inform your waiter about allergies when eating at a restaurant. In addition, some people may need to carry epinephrine shots to prevent a life-threatening reaction in case of accidental ingestion of a food. 

If you have a food intolerance or sensitivity, avoiding problematic foods can help prevent uncomfortable symptoms. For a condition like lactose intolerance, taking tablets that contain lactase before eating dairy products may be helpful. If you suspect you have a food sensitivity, working with a dietitian to try an elimination diet can be very helpful. Remember to discuss your concerns with your healthcare provider to figure out which interventions will be safe and helpful for you. 

Note from Healthy For Life Meals: We provide detailed ingredient information for all of our menus, so you don’t have to worry about not knowing about a food that doesn’t agree with you! If you’re interested in learning more about the best healthy meal service, check out our menus here.