Food allergy or intolerance?


From the level of publicity it receives, it can sometimes seem like everyone has a food allergy of one sort or another - whether it's dairy products, nuts or even chocolate. They do exist, however, and as we learn more about how food affects us, it's possible to identify specific triggers in the food we eat that can produce unpleasant symptoms. Here's our quick guide to allergic reactions and food intolerances.

Food allergies

An allergy is a response by the body's immune system to something (called an allergen) that is not necessarily harmful in itself. Certain people are sensitive to this allergen and have a reaction when exposed to it. Some allergic reactions are mild and harmless, but others are severe and potentially life-threatening (anaphylaxis). A food allergy is an abnormal reaction of the body's immune system to a particular food. This tends to cause unpleasant and unwanted effects (symptoms).

Food intolerances

Food intolerances are far more common , but the reasons why they occur are not fully understood. It's believed that they may be caused by an imbalanced diet - for example, if you eat too much refined food or a have a diet high in fats or insufficient dietary fibre. Small amounts of a particular food may cause your reaction, although some people report that they are able to tolerate a suspect food if eaten only occasionally or in small daily portions.

Some of the same symptoms associated with allergies may be present if you have a food intolerance. Stomach problems are particularly common, including bloating, constipation, diarrhoea and irritable bowel syndrome (IBS). Some people experience skin reactions such as eczema. The difficulty with diagnosing food intolerances is that your symptoms may occur some time after you have eaten the problem food and they may be fairly ambiguous, such as a headache or a feeling of lethargy.

Here's our advice for keeping your diet in the clear:

  • Keep a food diary to record what you eat and how you feel afterwards - over the first couple of hours if an allergy is suspected and over the next few days if you think you may have an intolerance.
  • Try eliminating the suspect food from your diet and see how you feel over the next few days. Then re-introduce the food to see if you suddenly feel worse - this is a good indicator of food sensitivity.
  • Take advice from your doctor if you identify a food to which you think you are intolerant.