Eating out at a good restaurant is one of life's finer pleasures. Unfortunately, we don't always wake up feeling on top form the next day, which is sometimes caused by overindulging but it can also be something more serious. One cause could be intolerance to something we have eaten, or we could even have experienced an allergic reaction.
While intolerance means our body is having a difficult time digesting something, an allergy leads to a reaction from the body's immune system. While some of these reactions are relatively harmless, some can be life-threatening.
The difference between an allergy and intolerance
There are different types of food allergy, largely depending on the type of immune reaction it triggers. If you have an allergy which leads to a sudden and acute reaction, your body will probably have created antibodies known as immunoglobulin E, or IgE. In the process of this reaction your body produces high levels of chemicals such as histamine, which causes many of the symptoms associated with an allergy. If a reaction is less serious or delayed, the chances are it was caused by a type of white blood cell called a T cell, and this is known as a non-IgE allergy.
Intolerances usually lead to digestive problems such as bloating and cramps, but these symptoms are not caused by the immune system. One of the big differences between intolerance and an allergy is the speed at which the symptoms start after eating. An allergic reaction is likely to show itself quickly, but the symptoms of intolerance may not appear until several hours after you have eaten.
How common are they?
Around six to eight per cent of children are thought to have some kind of allergy, while that figure is between three to four per cent in adults. 1 These allergies will vary in severity, and some of them may even be intolerances.
Recognising an allergy
Allergies have many symptoms, but some of the most common include eczema, loose and frequent stools or constipation, tiredness, gastro-oesophageal reflux and paleness. Allergies can also affect the growth of children, which is one of the reasons why children should be weighed and measured on a regular basis.
The most common symptoms of intolerance are stomach ache, loose stools and rashes, although there are other symptoms too. However, some of these symptoms can be caused by non-IgE allergies, so it can be difficult to know exactly what is causing the problem.
A number of foods are especially common allergens. These include:
- Nuts (especially peanuts)
- Seafood (especially shellfish)
- Some fruits, including kiwi
If you have concerns regarding a possible allergy, your first port of call should be your doctor. From there you can be referred to a specialist in hospital to set up tests, especially if you have previously experienced a severe reaction or anaphylaxis. This is also an option if your child isn't growing as expected.
Doctors can check for IgE allergies by testing your blood or by a skin prick test, while non-IgE allergies involve more of a trial and error approach. To take part in this you need to have a rough idea of the food type you think you are allergic to, and cut it out of your diet completely for a few weeks. This should remove all symptoms, and you can check to see if these symptoms return by re-introducing the food a few weeks later. If the food contains essential nutrients, your doctor should be able to help you plan to find an alternative source while you eliminate the suspect food from your diet.
Living with an allergy
If you discover you do have an allergy, the only way you can completely avoid it is if you cut that food out of your diet. This isn't always as easy as it sounds, but the laws on food packaging are particularly strict, so manufacturers have to take extra care when labelling foods, which should help. Getting a referral to a dietician can also be beneficial, especially just after diagnosis. Medication is also important, and anybody who has experienced anaphylaxis should carry an injectable form of adrenaline at all times.