The evidence for idiopathic food intolerance is more substantial than its opponents would have you believe.
One very well-conducted and interesting study involved children with severe migraine who were investigated by a research team at Great Ormond Street Hospital in London. These are children who are very difficult to treat successfully by normal means. On an elimination diet, 88% of those children got better – an astonishing number. Not just their migraine, but all sorts of other symptoms as well, including aching limbs, runny noses, asthma, eczema, diarrhoea, wind, mouth ulcers and hyperactivity. Some of these children also had epileptic fits, and even this symptom cleared up on the diet, recurring when culprit foods were tested. A notable feature of this study is that, of the five researchers involved, four were deeply sceptical at the outset. Their report notes that they embarked on this study believing that any favourable response, such as that claimed to substantiate the dietary hypothesis, could be explained as a placebo response. The positive double-blind controlled trial … provides clear evidence that a placebo response was not the explanation.’
Other studies with good scientific credentials have demonstrated a role for idiopathic food intolerance in adults with migraine, and for sufferers from irritable bowel syndrome and Grohn’s disease. There are also good studies of individual patients with rheumatoid arthritis and palindromic rheumatism (an episodic form of inflammatory arthritis) who have responded dramatically to avoidance of a particular food. Some of these patients were given several double-blind challenges and showed changes in certain immunological tests, as well as joint symptoms, when challenged with the offending food. This suggests that the immune system could be playing some part in these food reactions.