Bloating, diarrhea, vomiting—these are just some of the unpleasant symptoms that food allergies and intolerances can trigger.
It’s normal to experience stomach issues from time to time. But if you find yourself experiencing them on a regular basis, you may have developed a food intolerance or a food allergy.
You can still enjoy a healthy, balanced diet. But if you think you have a food intolerance or allergy, you should not try to diagnose it yourself and should talk with a medical provider. Food allergies and intolerances can be difficult to identify, and trying to resolve them on your own may lead you to eliminate foods from your diet unnecessarily.
Laura Manning, MPH, RDN, CDN
In this Q&A, Laura Manning, MPH, RDN, CDN, a registered dietitian at the Inflammatory Bowel Disease Center in The Mount Sinai Hospital, explains the differences between food intolerances and allergies, how to identify the symptoms, and how to seek help.
What are food allergies?
When someone has an immune response and produces an allergy antibody against a certain food, they have a food allergy. The most common food allergies are milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, and soybeans, which are behind a majority of food allergies in the United States, according to the Food and Drug Administration. Allergic reactions typically occur within minutes, or up to two hours after ingestion.
What are the symptoms of food allergies?
An allergic reaction occurs every time you eat a food you are allergic to. Common symptoms include coughing, wheezing, itching, lip tingling, rashes, mouth swelling, hives, throwing up, and breathing difficulties. In severe cases, food allergies can cause people to go into shock and can be life threatening. You can experience changes in blood pressure and narrowing of your airways, which can cause difficulty breathing or vomiting.
What are food intolerances?
A food intolerance may happen when you lack enzymes responsible for digesting a certain food or food group. A common example is lactose intolerance, in which a person lacks a key enzyme for digesting lactose, a sugar found in milk. Other common examples of foods that may be poorly tolerated are beans, garlic, mushrooms, onions, and watermelon. These are foods that are high in FODMAPS, or fermentable carbohydrates, including lactose, fructose, fructans, galacto-oligosaccharides, and polyols. These can rapidly ferment during digestion causing gas, bloating, diarrhea, and constipation when consumed in high amounts. Food intolerances typically develop in the gastrointestinal tract or the digestive system, and can sometimes be triggered by stomach infections. Certain gastrointestinal conditions, such as irritable bowel syndrome (IBS), can make someone more susceptible to FODMAP intolerances. Because FODMAPs are in a wide array of foods, it is important to seek help from a medical provider and trained dietitian to identify the foods causing the problem without completely eliminating them from a healthy diet.
What are the symptoms of food intolerances?
When you eat foods your body cannot digest, you will experience discomfort, including gas and bloating, and may also experience diarrhea, constipation, reflux, and gas.
What is the difference between food intolerances and food allergies?
Unlike food allergies, food intolerances do not involve the immune system, do not cause allergic reactions, and are not life threatening. People with food intolerances can usually have small amounts of these foods without a reaction, whereas those with allergies cannot. Those with food intolerances may even be able to acclimate themselves to these foods by eating small amounts over time, whereas those with food allergies cannot have even the smallest amount without a reaction. However, some food allergies may change or go away on their own with time, especially after adolescence. If you have a known food allergy, an allergist can help you safely retrial the foods you are allergic to.
How are food allergies diagnosed and treated?
A skin prick test, typically on the upper back or forearm, or blood test can identify food allergies. Because food allergies cannot be eliminated, you will need to avoid eating foods that trigger your allergies, including foods that have been manufactured in factories where those foods are also processed (a warning should be displayed on food labels). Working closely with a board certified allergist will help determine what your reactions are to certain foods and best treatments. You can schedule an appointment at the Elliot and Roslyn Jaffe Food Allergy Institute at the Icahn School of Medicine at Mount Sinai. You can also find qualified food allergists nationwide through The American College of Allergy, Asthma & Immunology.
How are food intolerances diagnosed and treated? Can I use a food sensitivity test?
Unlike food allergies, there are no official tests for food intolerances, which makes them more difficult to diagnose. While food sensitivity tests are available and popular, they are not FDA-approved, are unreliable, and frequently lead people to eliminate foods unnecessarily, which can lead to health issues. If you have an intolerance triggered by a FODMAP, going on a supervised food elimination diet, or low FODMAP diet, can help you identify the foods behind the intolerance. This diet involves eliminating high FODMAP foods and then slowly reintroducing them to identify the triggers. To avoid malnutrition, you should only go on this diet with guidance from a gastroenterologist and a trained registered dietitian. These experts will guide you through the process of identifying foods you are intolerant to and help you modify your diet in the healthiest way possible.