Food intolerance is not the same as a food allergy. Although it can cause considerable discomfort, an intolerance is much more manageable than an allergy, and symptoms are far less dangerous.Symptoms of food intoleranceBecause food intolerance is often caused by missing enzymes, symptoms are often related to the gut, and can include bloating, diarrhoea, constipation and irritable bowel syndrome (IBS).Unlike with an allergy, food intolerance reactions are usually delayed – occurring several hours and sometimes up to several days after eating certain foods.Common food intolerancesThe most common food intolerances are gluten, lactose, and wheat. If you have lactose intolerance, it means your body can't digest lactose, a sugar found in milk, yoghurts and soft cheeses. There are symptom relievers that can help.Wheat can be a difficult food to digest, and can trigger bloating and stomach pain. Cutting out bread or trying wheat-free alternatives may help.It’s also possible that your intolerance is not to a type of food, but to additives and preservatives such as MSG, caffeine, artificial sweeteners or colours.Keeping a food diaryThe best way to determine if you have a food intolerance is by keeping a food diary and noting any symptoms after eating certain foods. Ask your doctor if it is a good idea to try eliminating suspected foods for a few weeks.Coeliac diseaseAn intolerance to gluten is sometimes confused with coeliac disease – a lifelong disease in which the body attacks the lining of the small intestine when someone eats gluten. People diagnosed with coeliac disease must eliminate gluten from their diet completely.