Allergy or intolerance?

If the reaction activates the body’s immune system, triggering an antibody response, it’s an allergy. But if the reaction doesn’t trigger the immune system, it’s an intolerance. Common food intolerances involve substances that are difficult to process, such as lactose or gluten. Symptoms vary, but might include bloating, stomach pain, wind, fatigue and headaches. The onset of food intolerance symptoms is usually slower and may be delayed by hours after eating problem foods; the symptoms may also last for many hours. Food intolerances are rarely life-threatening.

Peanuts

About 1 in 50 children and 1 in 200 adults have a peanut allergy. Peanut allergy usually persists into adulthood – the higher numbers among children reflect the rise in people affected. Symptoms are often mild, but are sometimes life-threatening. Peanuts are the most common cause of anaphylactic reactions and death. Symptoms often start quickly, within an hour of coming into contact with peanuts, sometimes within minutes. Peanuts can be listed as ground nuts, beer nuts, mixed nuts and monkey nuts. Download the Foodmaestro app, developed by dietitians at Guy’s and St Thomas’ NHS Trust, to help you check if a product is safe.

Shellfish

Seafood is one of the most common allergies in adults and can develop at any time. Common culprits are prawns, crab and lobster. Symptoms include swollen lips and face, itching, hives and vomiting, but can be more severe. Sufferers must avoid all shellfish, including foods such as Worcestershire and oyster sauce.

Wheat

Wheat allergy is a reaction to proteins in wheat, triggered by the immune system, and usually occurs within minutes to hours of eating. Symptoms include rhinitis, asthma and hives. This isn’t to be confused with coeliac disease, which affects about 1 in 100 people. Coeliac disease is an autoimmune condition, which means the body attacks itself when gluten is eaten. There’s no cure and sufferers need to follow a gluten-free diet, otherwise damage to the gut lining occurs. Around 13% of people claim to have non-coeliac gluten sensitivity – there’s some debate as to whether it’s caused by gluten or other wheat components. Symptoms often improve on a diet low in windcausing carbs called FODMAPS.

Getting tested

If you strongly suspect you or a family member may have a food allergy, see your GP, who may refer you to a specialist for testing. You’ll probably be given a skin-prick test or blood test, or put on an elimination diet. Steer clear of self-test kits and highstreet tests, such as IGG antibody testing, Vega testing, hair analysis, iridology, pulse testing and kinesiology – these have no scientific basis, are unreliable and have no useful role in the diagnosis of food allergy.