Physiological effects of starvation interpreted as food allergy.

It is a common misconception that food allergy can cause a wide variety of symptoms. A population study in the English town of High Wycombe showed a perceived prevalence of food intolerance of almost 20%, but double blind food challenge (the definitive test) provided objective evidence of symptoms related to food in fewer than 2% of subjects. This popular belief is fuelled by extensive and often misleading reports on the subject, as well as the emergence of clinics offering unvalidated tests that claim to diagnose allergy. We describe three patients who undertook strict, low carbohydrate diets because of perceived allergy. Starvation may affect the response to an oral glucose challenge. It results in an initial excessive rise in the blood glucose concentration followed by hypoglycaemia, which can be accompanied by symptoms. 4 All three of the patients described developed symptoms several hours after meals and attributed these to food allergy. Further restriction of carbohydrate intake exacerbated their problem. Symptoms continued to occur after meals and were erroneously interpreted as further evidence of their carbohydrate allergy.