Unpleasant reactions to food

Unpleasant reactions to food Extension

Learning objectives • To understand there are many different reasons for unpleasant reactions to food. • To know which foods may cause a food intolerance and/or allergy. • To recognise the symptoms of food intolerance and/or allergy. • To understand the severity of peanut allergies. • To recognise the seriousness of anaphylaxis. • To understand the terms oral allergy syndrome and exercise induced food allergy. • To define the term food aversion. • To understand the cause and effects of lactose intolerance and coeliac disease.

Food intolerance Most people can eat foods without any problems although they may have different likes or dislikes that influence what they choose. However, some people react to certain foods and eating them may cause uncomfortable symptoms or, in rare cases, a severe illness.

Assistance with a food intolerance It is important that people who think they suffer from a food intolerance do not cut out important foods. This could mean people miss out on important nutrients and can affect the results of allergy tests. Some allergy and intolerance tests are advertised in magazines, in the shops and over the internet. For many of these tests there is no evidence that they are reliable.

Assistance with a food intolerance People with food intolerance or allergy concerns should take advice from a doctor or dietitian to make sure that the medical condition is properly diagnosed. Care needs to be taken to ensure that their diet contains a wide variety of foods to provide all the nutrients they need, particularly the nutrient/s normally provided by the foods they cannot eat. It is important to consume a healthy and varied diet for good health.

The eatwell plate The eatwell plate is the UK guide to help people achieve a health and varied diet for good health.

Reasons for food intolerance There are many reasons for unpleasant reactions to food. A general term for those that are not cause by food poisoning are food intolerances. Most unpleasant reactions to food are not true food allergies. A food allergy is one particular type of food intolerance that involves the body’s immune system. Food intolerances may cause uncomfortable symptoms, but only true allergies involve the immune system.

Food allergies The immune system is part of the body’s defence system, as it protects against foreign organisms like bacteria and viruses. In some people, I may also react to substances in foods, or in the environment, e.g. pollen or animal fur. This abnormal reaction is known as an allergic reaction. The symptoms of an allergic response may be very similar to those of a food intolerance, but potentially more severe. They can also resemble those of other illnesses. Proper diagnosis, therefore, is very important.

Causes of allergic reactions Most foods may cause an allergy, but, listed below are the most common allergic reactions to food in Europe. These ingredients must be labelled on food packaging. • celery; • cereals containing gluten (wheat, rye barley and oats); • fish, molluscs, and crustaceans (including prawns and crabs); • lupin (seeds similar to legumes); • cow’s milk and milk products. • mustard; • nuts (including Brazil nuts, hazelnuts, almonds, and walnuts); • peanuts • sesame seeds; • soya; •sulphur dioxide or sulphites (preservatives).

Children and food allergy Allergies tend to run in families. The most common food allergy reactions in childhood are to: • eggs; • cow’s milk and milk products; • nuts (including peanuts); • soya; • wheat. It is common for most children to grow out of food allergies early in their childhood.

Symptoms of food allergies A food allergy usually occurs between a few minutes and a few hours after eating a particular food. The symptoms of food allergies vary from person to person and can include: • coughing; • dry, itchy throat and tongue; • nausea and feeling bloated; • wheezing and shortness of breath; • swelling of the lips and throat; • runny or blocked nose; • sore, red and itchy eyes.

Peanut allergy In extremely rare cases, a severe allergic reaction called anaphylaxis can cause death. An example of this is a serious allergy to peanuts or other nuts. Peanut allergy has become more common, especially in children. Until recently, the UK government recommends that, where there is a family history of allergy, pregnant mothers should not eat peanuts, and that peanuts are not given to infants.

Anaphylaxis A severe allergic reaction can sometimes lead to anaphylaxis. When someone has an anaphylactic reaction, they may have serious symptoms in different parts of the body at the same time. These symptoms can develop within minutes. This severe reaction can be fatal if it is not treated immediately. Treatment is usually an injection of adrenaline (epinephrine). Most people with severe allergies will have this with them whereever they go.

Anaphylaxis Anaphylaxis is most commonly caused by food allergies, but can also be caused by other things, such as insect bites and drug allergies. Peanuts, milk, eggs and fish are the most common foods to cause anaphylaxis in the UK.

Oral allergy syndrome Foods such as fruit and vegetables can cause reactions such as itching or rashes around the lips and mouth. This is called oral allergy syndrome and is a symptom of a food allergy. It is usually only seen in people who get hay fever. Cooking often destroys the allergies that trigger this reaction, for example people who react to raw apple might be able to eat cooked apple.

Trends in intolerances and allergies Food intolerance is more common in children than in adults. Children often grow out of the problem before they go to school. The Food Standards Agency estimates that as many as 20% to 30% of people in the UK think they suffer from some kind of food intolerance. However, surveys have shown that only about 1- 2% of adults in the UK have a food allergy that can be detected by rigorous tests.

Food aversion Some people’s symptoms only occur if they know that they are eating a particular food – they do not occur if the food is disguised. This is called food aversion. It may be because they believe the food will cause symptoms, or because the food has been associated with illness in the past.

Lactose intolerance One type of food intolerance is caused by the lack of an enzyme that is needed to digest a component of food. The most common example of this is lactose intolerance where sufferers have low levels of the enzyme needed to digest lactose, the sugar found in milk. Lactase breaks down the lactose so that it can be absorbed.

Lactose intolerance Children are usually born with sufficient lactase but in some parts of the world, levels fall rapidly after childhood. Lactose intolerance is typically seen in adults and is more common in Africa, India and South America. In the UK, Ireland and northern Europe, only 5% of the population is affected, to varying degrees.

Lactose intolerance If lactase levels are low, undigested lactose passes into the large intestine where it causes pain and diarrhoea. Lactose intolerance is common in some ethnic groups, particularly where adults do not traditionally drink milk. People with lactose intolerance can usually drink small amounts of milk, yoghurt and eat cheese without problems. If symptoms are severe, alternative sources of calcium must be eaten.

Coeliac disease Coeliac disease is a reaction to gluten, a protein found in cereals such as wheat, rye and barley. The gluten damages the small intestine so people with coeliac disease cannot absorb nutrients from food normally. Sufferers typically have stomach pain and diarrhoea after eating foods that contain gluten. Coeliac disease is usually first noticed in childhood, but can go undetected into adulthood. In order to diagnose coeliac disease, patients need to be consuming gluten. It is important that people seek medical advice rather than simply changing their diet.

Coeliac disease The disease can affect growth or cause weight loss. People with coeliac disease must avoid foods that contain gluten throughout their life, for example, bread cakes, and biscuits. Many foods have small amounts of wheat, barley or rye added, so people with coeliac disease must check food labels carefully. Rice, maize and potatoes do not contain gluten so are good sources of starchy carbohydrate , and gluten-free versions of foods such as bread and pasta are available. Coeliac disease may affect as many as 1 in 100 people in the UK; some of whom do not know they have the disease.

Review of the learning objectives • To understand there are many different reasons for unpleasant reactions to food. • To know which foods may cause a food intolerance and/or allergy. • To recognise the symptoms of food intolerance and/or allergy. • To understand the severity of peanut allergies. • To recognise the seriousness of anaphylaxis. • To understand the terms oral allergy syndrome and exercise induced food allergy. • To define the term food aversion. • To understand the cause and effects of lactose intolerance and coeliac disease.

For more information visit www.nutrition.org.ukwww.foodafactoflife.org.uk

Unpleasant reactions to food