Overview
Food intolerance means your body has trouble processing certain foods or ingredients. This may happen because of problems digesting a substance, sensitivity to a chemical in food, or reactions to additives. Unlike food allergy, food intolerance does not usually involve the immune system.
Key Symptoms
Common symptoms include bloating, gas, stomach cramps, nausea, diarrhea, and sometimes headache or flushing. Symptoms often start after eating a trigger food and may vary from mild to disruptive. Some people only react when they eat a larger amount.
Causes and Risk Factors
Food intolerance can happen for several reasons. Examples include low levels of digestive enzymes, such as in lactose intolerance, sensitivity to naturally occurring food chemicals, or reactions to additives like sulfites in some foods and drinks. Other digestive conditions, stress, and eating large portions may make symptoms more noticeable.
Who Is Affected
Food intolerance can affect children and adults. Some types are more common in certain populations, such as lactose intolerance in many parts of the world. People with irritable bowel symptoms or other digestive problems may be more likely to notice food-related symptoms.
Diagnosis and Tests
There is no single test for every type of food intolerance. A healthcare professional may ask about your symptoms, diet, medical history, and timing of reactions, and may suggest a food diary or an elimination-and-reintroduction plan. Testing may be used to rule out other conditions such as food allergy, celiac disease, infection, or inflammatory bowel disease.
Treatment Categories
Treatment usually focuses on identifying and reducing trigger foods while keeping the diet balanced. Some people can tolerate small amounts, while others need to avoid a specific ingredient more carefully. Support from a doctor or dietitian can help prevent unnecessary food restrictions and reduce the risk of missing important nutrients.
Diet and Lifestyle
Reading food labels can help you spot common triggers and additives. Eating smaller portions, noticing whether symptoms change with stress, and keeping regular meals may also help some people. If you avoid major food groups such as dairy or wheat, ask a healthcare professional how to meet your nutrition needs.
When to Seek Medical Care
Seek medical care if symptoms are frequent, getting worse, or affecting eating, work, school, or sleep. You should also get checked if you have weight loss, ongoing diarrhea, blood in the stool, vomiting, signs of dehydration, or symptoms after many different foods. A clinician can help find the cause and check for conditions that need treatment.
When It May Be an Emergency
Food intolerance itself is not usually an emergency, but symptoms after eating can sometimes be caused by food allergy instead. Get urgent help right away for trouble breathing, swelling of the lips or tongue, widespread hives, fainting, severe weakness, or sudden severe vomiting after a food. These can be signs of a serious allergic reaction.
Questions to Ask a Healthcare Professional
You may want to ask which foods are the most likely triggers, whether testing is needed, and how to safely try an elimination plan. Ask how to tell food intolerance apart from food allergy, celiac disease, or other bowel conditions. If you need to avoid certain foods, ask how to maintain balanced nutrition.