The Differences Between Food Allergies and Intolerances
Here's how to tell which you're suffering from—and when to see a doctor.
If you've ever experienced an uncomfortable rumbling in your stomach after eating a specific food, you've likely considered the possibility of an allergy—but the language surrounding food-related allergies can be confusing, especially when you throw intolerances into the mix. Treating your symptoms, however, starts with understanding the differences between allergies and intolerances; it culminates in testing to determine which you're experiencing.
According to Dr. Melissa Iammatteo, Chief of Allergy and Immunology at Westmed Medical Group, the main difference between a food allergy and an intolerance is the involvement of the immune system: Allergies trigger an immune response, while an intolerance typically impacts the digestive system. "While some of the symptoms of food allergy and intolerance may overlap, it is important to know the difference," Dr. Iammatteo says. "A food intolerance may make people feel unwell, but a true food allergy could be potentially life-threatening." Ahead, everything you need to know about both, from symptoms and diagnosis to management.
Distinguish an immune response from a digestive disorder.
With a true food allergy, the immune system identifies something you eat as an invader. "Therefore, it attacks the food by producing an antibody called immunoglobulin E (IgE), directed specifically against the culprit food, which leads to an allergic reaction," she says. "With a food intolerance, the digestive system has difficulty breaking down the food. Therefore, symptoms primarily involve the gastrointestinal system with abdominal pain, nausea, vomiting, or diarrhea."
Allergy symptoms are often more severe.
Dr. Iammatteo says that people with food intolerances can typically eat small amounts of the offending food, while people with food allergies cannot eat any amount. "For instance, a person with lactose intolerance who has a deficiency in the enzyme required to digest lactose may be able to tolerate a splash of milk in coffee, but will experience gastrointestinal symptoms if he or she drinks a full glass of milk," she says. Those who experience allergic reactions exhibit symptoms (including hives, itchy skin, rashes, itchiness of mouth/throat, swelling of the face, lips, tongue, and airway, shortness of breath, wheezing, chest tightness, nausea, vomiting, abdominal pain, diarrhea, lightheadedness, dizziness, or loss of consciousness, or even anaphylaxis) ranging from mild to severe, which will occur almost immediately after ingesting the food—and will occur consistently with each and every exposure to the allergen.
Signs of an intolerance typically occur within the digestive pathway.
With a food intolerance, however, the digestive system simply has difficulty breaking down the food; symptoms can be more gradual in onset and should primarily involve the gastrointestinal system. Abdominal pain and cramping, bloating, nausea, vomiting, diarrhea, or heartburn are all indicators that an intolerance is the root of your problem.
Both ailments merit a trip to the doctor—but allergies need to be addressed as soon as possible.
Dr. Caesar Djavaherian, an emergency room medical doctor and co-founder of Carbon Health, says that all patients who have experienced allergic reactions should evaluated by a doctor, so they can come up with a plan of action in case they are accidentally exposed to the allergen again in the future—especially since allergic responses can vary dramatically and change over time. "So, the mild peanut allergy may become a life-threatening reaction without warning," he says. "Food allergic people should be prepared with the appropriate medications to treat themselves should this happen, since it may mean the difference between life and tragic, avoidable death."