You only have to open a magazine or turn on the TV to notice food allergies and intolerances are becoming more prevalent.
There are an estimated 2 million adults in the UK that suffer from at least one allergy (Mintel 2010), and with that UK admissions to hospital have increased by 500 % since 1990 (Gupta 2007). Whether it is a peanut allergy or a lactose intolerance, you now hear all too often someone announcing they are excluding something from their diet.
So why are we seeing such a significant rise of food allergy in the UK? There are various credible suggestions such as changes in the food we eat over the years, environmental factors, poor hygiene and genetics, but no definitive answer.
Allergy or Intolerance?
The differences that exist between food allergy and food intolerance are commonly misunderstood. In food allergy the body’s immune system mistakes a particular food as a harmful substance and acts against it releasing chemicals such as histamine which cause an allergic reaction. The onset of a reaction is usually within minutes to 2 hours of food ingestion (Robison & Pongracic 2012). Symptoms vary considerably between individuals presenting in minor ways such as rashes, itching, hives, or swelling, or more seriously by restricting the airway. As a result, a food allergy can be fatal.
If food sensitivity does not involve the immune system then it is classed as an intolerance. Intolerances can be caused by a variety of factors; for instance, a lack of specific digestive enzymes or a sensitivity to certain food factors such as caffeine or additives. Most individuals can tolerate small amounts of the food to which they are intolerant, with the resultant symptoms milder than those with an allergy. The symptoms can take days to develop and some can simply leave you with a general feeling of lethargy and “unwellness”. It is therefore much harder to identify the food that is causing discomfort. As with allergies, symptoms vary between individuals and can present as fatigue, bloating, irritable bowel, joint pains, rashes, eczema and migraine. Whether you’ve been experiencing bloating since childhood or have developed migraine in your middle ages, food intolerances do exist but are harder to identify.
Common problem foods and how to avoid them
The most recognised food allergens are cow’s milk, nuts, eggs, soya, wheat, shellfish, peanuts and fish. The extent to which food allergy can be prevented is still not clear. The Department of Health (DOH) recommend breast feeding for the first 6 months of life which may offer protection against some allergies later in life, though evidence behind this is still sketchy. Advice used to state that pregnant and breastfeeding mothers avoid allergens such as peanuts and shellfish but the DOH changed this advice in 2009, giving mothers the go ahead to eat these foods safely during pregnancy. There are still no definitive answers about why allergies develop and how we can stop them from developing. However, we can take steps to minimise allergies developing during infancy, such as not weaning your baby before 17 weeks, and ensuring that foods known to cause allergies (e.g. peanuts, eggs) are introduced in small amounts after 6 months.
If allergy is suspected, then diagnosis is easy through reliable blood and skin tests available throughthe NHS. There are many tests available on the high street, for example hair analysis; however scientific and clinical evidence behind these are limited and many practitioners advertise the ability to diagnose without clear indication of training or expertise. These tests risk either missing the allergen or producing long lists of foods that should be avoided, therefore putting the individual at nutritional risk due to unnecessary food exclusion.
Food allergies should not be dealt with alone, and once diagnosed by a healthcare professional, support from a Registered Dietitian should be sought to ensure elimination of the food allergen and maintenance of a balanced diet.
If food allergy testing is negative, the gold standard of identifying food intolerance is to keep a strict food and symptoms diary and then, under instruction by a Dietitian, carrying out an elimination diet. Once single or multiple foods have been removed from the diet, each food is reintroduced individually. It is hopeful that the problem food can be isolated. Manipulative dietary investigations should not be taken lightly. Starting an elimination diet takes dedication and time, and the symptoms should be sufficiently debilitating to justify the periods of inadequate nutritional intake. However, if the food that is causing you problems is identified, it can be life changing.
The only real treatment for food allergy and intolerance is food avoidance, however medication such as creams, antihistamines and adrenaline could help control the symptoms, and may be prescribed by your Doctor.
Sensitivity to nuts and seafood are rarely lost, but children will often grow out of the more common allergies such as egg, milk, wheat and soya. This may be due to the development and maturation of the gut or of the immune response that cause allergy in the first place. Adults can develop tolerance to the allergen through elimination and supervised re-introduction of the food after 1-2 years, but this does not always happen, and some individuals will have to live with a life of learning how to deal with food exclusion to control their symptoms.
Having a food allergy or intolerance can be incapacitating. Once identified, eliminating the guilty food can improve your quality of life substantially. It is essential however that expert guidance is taken from a health care professional to ensure accurate identification and safe avoidance of the allergen while ensuring a balanced diet is maintained.