Genuine food allergy is rare. About 2% of the population (and 8% of children under the age of 3) are affected.
Food intolerance is more common. Allergy UK estimates that up to 45% of people in the UK suffer from food intolerance symptoms, including migraines, skin rashes and digestive problems.
What is a food allergy?
A food allergy is a rapid and potentially serious response to a food by your immune system. It can trigger classic allergy symptoms such as rash, wheezing and itch.
The most common food allergies among adults are to nuts – including peanuts, walnuts, hazelnuts and brazil nuts – fish and shellfish. Children often have allergies to milk and eggs as well as to peanuts, other nuts and fish.
What is a food intolerance?
Food intolerances are much more common than food allergies. The symptoms of food intolerance tend to come on more slowly, often many hours after eating the problem food. Typical symptoms include bloating and stomach cramps. It’s possible to be intolerant to several different foods. This can make it difficult to identify which foods are causing the problem.
Food intolerances can also be difficult to tell apart from other digestive disorders that can produce similar symptoms, such as inflammatory bowel disease, gastrointestinal obstructions or irritable bowel syndrome (IBS).
Types of food intolerance
Lactose intolerance, coeliac disease and wheat intolerance are types of food intolerance.
Lactose intolerance, sometimes known as dairy intolerance, occurs when your body can't digest lactose. Lactose is in milk and dairy products such as yoghurts and soft cheeses. The main symptoms are diarrhoea and stomach pain. In most cases, your GP can diagnose lactose intolerance by looking at your symptoms and medical history.
Coeliac disease is a gut disorder caused by gluten intolerance. Gluten is a protein found in wheat, rye and barley, which damages the intestine of sufferers. Symptoms include diarrhoea, wind, weight loss and mouth ulcers. About one in 100 people in the UK have coeliac disease. Around half a million aren't diagnosed. Your GP can accurately diagnose coeliac disease quickly and easily with a blood test.
Sometimes it isn't clear which food is causing a problem. The only reliable way of identifying such a food intolerance is through an exclusion diet, where you cut out certain foods from your diet one at a time to see if there's an effect.
Treatments for food allergy and food intolerance
In the case of a food allergy, you'll have to avoid the food you're allergic to. You may be able to eat the cooked versions without any problems, for example with fruit or vegetable allergies.
With lactose intolerance, you'll have to reduce the amount of dairy food that you eat.
With coeliac disease, you must avoid gluten for life.
With other forms of food intolerance, you'll have to stop eating the food for a while, or possibly for life.
In all cases, always read food labels carefully, and learn where your problem food may be used as an ingredient in other foods.
For more advice on your diet, ask your GP to refer you to an NHS dietitian.
