Go out to a restaurant with friends, or take your child to a birthday tea, and chances are there will be someone there who cannot eat something because of a food allergy.
But true allergic reactions to food are actually far less common than most of us imagine, according to Professor Barry Kay, consultant allergist at the London Clinic. "Food allergy, which happens when someone eats a particular food and their immune system produces what we call IgE antibodies, causing a particular set of symptoms immediately or shortly after eating the offending food, is clear-cut, uncontroversial, and can be confirmed scientifically by an allergy test," he says. "It can also be extremely serious."
In fact, if you have a severe food allergy, eating even a minute amount of the wrong food can cause a severe reaction called anaphylaxis: breathing difficulties, swelling of the lips and throat, abdominal pain, vomiting, collapse and, in the worst case scenario, death.
Allergy or intolerance?
Experts still do not know how many of us are affected by food allergy. Although around 30 per cent of people claim to be allergic to one or more foods, only one to two per cent of adults have a true food allergy and five to eight per cent of children. However food intolerance is far more common and may affect as many as 45 per cent of people.
While food allergies normally occur in reaction to a fairly limited number of foods, food intolerance reactions are more idiosyncratic and occur when you eat foods that most people can tolerate without a problem, making them quite hard to diagnose.
Symptoms of food intolerance can be caused by lack of the enzymes needed to digest certain foods. For example lactase, an enzyme needed to digest the milk sugar lactose, causing lactose intolerance. They can also be caused by an abnormal sensitivity to certain ingredients in foods, additives and preservatives, such as tyramine, found in mature cheeses and yeast extract, as well as certain wines, that cause migraine.
Coeliac disease, which is not an allergy or an intolerance but a unique and complex immune reaction, can trigger symptoms when an affected person eats gluten, a protein found in bread, pasta, biscuits, and a host of other foods containing wheat, barley, rye and, to a certain extent, oats. This damages the surface of the gut, making it hard to absorb certain nutrients.
AXA PPP Healthcare has provided the following advice to help people to understand if their health is being affected by a food allergy, intolerance, or coeliac disease.
Ten common culprits
You can get an allergic reaction to any food, but the top offenders are peanuts and products containing peanuts; soya and soya products; egg and egg products; milk and milk products; fish and fish products; wheat and products containing wheat; shellfish; fruit such as apples, pears, kiwi fruit, and peaches; vegetables such as potatoes, carrots, celery, and parsnip; and tree nuts and products containing tree nuts, including almonds, Brazils, hazelnuts, cashews, macadamia, pecan, pine nuts, pistachios, and walnuts.
Babies and children under three are most at risk of food allergy and intolerance, because their digestive and immune systems are immature. The good news is that most grow out of food allergies by the time they reach school age. However, an estimated four out of five children with a peanut allergy, one of the foods most likely to trigger severe allergic reactions, will stay allergic for the rest of their life.
Allergies can persist into or emerge for the first time in adulthood. Doctors still do not know the reason, although people with a family or personal history of asthma, eczema, hayfever, and other allergies are more at risk.
If you are hypersensitive to food then you need to read labels. All pre-packed foods and drinks must, by law, be clearly labelled if they contain celery, gluten, shellfish and other crustaceans, eggs, fish, lupin (a common garden plant, seeds from some varieties are sometimes used to make flour ), milk, molluscs such as mussels and oysters, mustard, tree nuts, peanuts, sesame seeds, soybeans, or sulphur dioxide and sulphites above 10mg/kg, or 10mg/litre.
Some food manufacturers will also use phrases such as 'may contain' nuts, eggs, milk, soya, etc, to show that there could be small amounts of these foods present in the ingredients, or because the food may have been contaminated accidentally during manufacture.
Unpackaged foods from restaurants, delis, take-away food outlets and bakeries can be trickier, as they do not have to be labelled. When eating out warn the staff that you or your child has an allergy and make sure both the chefs and the waiters know so they can avoid cross-contamination of your meal with other diners' food. Be aware of hidden allergens, for example in desserts which may contain nuts (eg, in a cheesecake base ), and sauces which contain wheat and peanuts.
Diarrhoea and/or constipation
Burning sensation in the skin
Tightness across face and chest
Tiredness and lethargy
Aches and pains
If any of these occur hours or days after eating a food, you could have a food intolerance.
Symptoms of a food allergy include:
Tingling or burning lips/mouth
Swelling of lips, face, or throat
Itchy, blotchy rash
Hoarseness (caused by swelling of the voice box )
Dizziness and lightheadedness
Nausea and/or vomiting
Red, irritated eyes
These symptoms generally occur immediately or shortly after eating a particular food.
If you experience diarrhoea, abdominal cramps, anaemia, recurrent mouth sores, or skin rashes after eating wheat, rye or oats, you could have coeliac disease.