People can have food allergies or food intolerances, and those unfamiliar with the terms may find them confusing.
Food allergies are a diagnosable response to an allergen. The immune system responds negatively to the allergen, causing internal or external symptoms that may be mild or severe. Common food allergies include shellfish, milk, nuts, and peanuts.
Food intolerances don't affect the immune system. They're chemical responses to specific ingredients or foods and affect your digestive system. Common food intolerances include gluten, lactose, and caffeine.