As a nutritional therapist I am often asked what the differences are between food allergies and intolerances. The words are often used wrongly, leading to confusion and misunderstanding, so let me try to set the record straight.
Allergies are fast acting reactions after exposure to an allergen. These reactions can be anything from skin rashes to swelling of the tongue and wind pipe, which can be life threatening if not dealt with quickly. Most people are only allergic to 1 or 2 foods but even trace amounts of these allergens can cause problems for those affected. Allergies can be tested for via the GP, and are known as IgE or anaphylactic reactions. They are long term, and once you have an allergy you can’t change the immune system, so you must be careful for the rest of your life. Only 2% of adults and 6-8% of children in the UK are thought to have food allergies, nuts, eggs, milk, fish and shellfish are the most common examples.
Intolerances are much more difficult to diagnose or even realise you have them. Reactions can take up to 72 hours to occur and multiple foods can be the cause. Intolerances can be outgrown, and over time food intolerances can change. The reactions can affect any organ system, often the digestive system and skin, but also mood and respiratory systems are involved, and even joints and muscles causing arthritic pain and stiffness. It is estimated that 45% of the population has at least one food intolerance. Testing for intolerances can be carried out, but not usually within the NHS, and a cost is usually incurred, going to see a private practitioner. I would recommend getting an IgG immunological test carried out, as these have a scientific basis and studies to back up the efficacy of the results.
Trying to manage suspected food allergies can be difficult and time consuming, but sometimes can be guessed at (an educated guess) before going to the expense of a test. Keeping a food diary, with an extra column to jot down symptoms can be quite revealing. You need to be quite precise about writing everything down, including timings, but over a few weeks it may be possible to see patterns emerging. Jotting down things like bowel movements, sleep quality, energy levels and obvious symptoms such as itching, or wheezing may show up links with foods you would not normally suspect. However if these foods are regulars in your diet (wheat, dairy, eggs are common offenders), it becomes a bit more difficult to tie the symptoms to the foods.
Often people try giving up the obvious foods, but don’t feel that it has made any difference to them. This is common when giving up wheat or dairy foods. As a practitioner I often suggest taking one or both of these foods out of the diet, but I also use supplements to help the gut heal, while removing the offending foods, and then slowly re-introducing them after a 4-6 week period. The supplements can make a big difference at this stage. Sometimes there is no difference in symptoms, and I often suggest an allergy test at this point, otherwise the guessing game can go on for a long time, and it can become very tiring and difficult to stick to. If people are seeing an improvement often they decide they don’t want to go back to the offending foods, or they start to re-introduce them one at a time, and in a measured way. On day one eat 1 portion (ie 1 slice of bread), on day 2 eat two portions and on day 3 eat three portions, keeping a diary and a note on any symptoms or changes in mood etc. Each of the excluded foods can be brought back into the diet like this, and then you know which has caused most problems. It is a little bit like weaning a baby. If you are giving up dairy, re-introduce cheese, yogurt and milk separately so you can see if one type of the food has a bigger impact on symptoms than others.
Food intolerances can be battled, and it may be that you can tolerate a small amount of the offending food, but not eat it all of the time. There is a balance to be found between missing out on your favourite foods and having your symptoms, it is amazing how quickly you can learn to listen to your body and manage things much better, once you have worked out what it is you are reacting to.
Polly Douglas is a nutritional therapist working in Edinburgh and Bridge of Allan. She can be contacted on 07837 100 642 if you would like to discuss symptoms or food intolerance testing. www.pollydouglasnutrition.com