Bad medicine: food intoleranceBMJ 2013; 346 doi: https://doi.org/10.1136/bmj.f529 (Published 30 January 2013) Cite this as: BMJ 2013;346:f529
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Des Spence doubts the existence of non-coeliac gluten intolerance because of lack of scientific evidence (BMJ2013;346:39). I wonder if he has spoken to his patients? I am sure he would find some of them, like me, have recognised a temporal link between their symptoms and gluten ingestion. I have had muscle pain and headaches for decades. I did not seek medical advice because as a doctor I did not want to be labelled as having fibromyalgia induced by the stress of working for the NHS! It has only been in the last 4 years I have realised my symptoms are induced by certain foods and following change of diet I am now symptom free (except with wheat-induced relapses). I did not consult my GP or colleagues, because I would have expected the scepticism that so many non-atopic food-intolerant patients face from many in the medical profession. If I eat wheat it is followed by a headache within 20 minutes and muscle pain after about 2 hours. Very small quantities are sufficient to trigger symptoms and I have had numerous inadvertent ‘blind challenges’. I did not expect dry roast peanuts to contain wheat but some brands do.
The term non-coeliac gluten intolerance will cause problems, because some patients report symptoms triggered by a wide range of foodstuffs. I react adversely to many gluten-free products including buckwheat, which is thought to be gluten free and botanically is not related to the cereals. As there is no laboratory test, dietary exclusion is the only way of recognising these food-induced problems and patients (and their doctors) may think they have excluded a dietary cause of their symptoms because omitting only gluten from their diet did not improve their symptoms.
Des Spence should remember that a lack of evidence simply means we should look more closely at a problem, not that the problem does not exist.
Competing interests: No competing interests
In his piece on ‘Bad Medicine: Food Intolerance’ Dr Spence berates ‘the allergy industry’ for jumping on the profitable but totally 'unscientific' food intolerance/gluten-sensitivity bandwagon.
And he is certainly right about the 'unscientific'. There is indeed very little scientific knowledge about food intolerance or non-coeliac gluten sensitivity. But the fact that we know little about them does not mean that they do not exist - merely that we do not know much about them. Until Copernicus discovered that the earth went round the sun we did not know about that either – but that had not stopped it doing so for billions of years.
While IgE mediated allergy (an immediate, immune system reaction such as peanut allergy), and classic coeliac disease, have been widely researched and are reasonably well understood, delayed reaction food sensitivity and ‘non-coeliac gluten sensitivity’ have scarcely been studied at all and are, therefore, scarcely understood at all.
However, there is a significant proportion of most Western populations who suffer from either chronic or intermittent, indeterminate, ‘idiopathic’ ill health (irritable bowel syndrome, fatigue, joint pains, chronic headache, low level depression etc etc etc). In the vast majority of these cases their GPs can provide them with neither an explanation nor a treatment for their conditions.
While some of these patients continue to suffer in silence (or to clog up their GPs waiting lists) others seek an answer elsewhere – some experiment with homeopathy, or yoga, or Traditional Chinese medicine, others attribute their ill health to a ‘food intolerance’ or, more recently, to gluten sensitivity.
(And before Dr Spence dismisses ‘gluten sensitivity’ as a industry driven fad, maybe he should read this paper, published early last year, by many of the most respected names in coeliac research, Spectrum of gluten-related disorders: consensus on new nomenclature and classification  – especially the concluding paragraph; a further article in this very journal last November  and take a look at the clinical trails now underway in Boston and in Naples. )
However, although attributing ill health to a food intolerance may seem an easy answer, actually pinpointing the offending food is far less easy. Currently ‘medical science’ has nothing to offer but an ‘elimination and challenge’ diet, a diagnostic tool that takes a great deal more time and commitment on the part of both the patient and their medical practitioner than either are usually prepared to commit to.
While IgG ‘allergy/intolerance’ tests (such as the York tests mentioned by Dr Spence) may of dubious scientific validity (you do not have to be either allergic or intolerant to a food to create IgG antibodies to it) at least they do offer some guidance and eliminating the foods pinpointed by their tests does very often improve that person’s symptoms – although this may often have as much to do with focusing that person's attention on what they are actually eating as it has to do with an intolerance.
Given that the average Western diet leaves a lot to be desired in terms of nutritional balance, adopting a diet with a more balanced nutritional profile may already be enough to favourably affect a sufferer’s health. An interesting study carried out in 2005 for the Allergy Research Foundation found that the symptoms of around 50% of general practice patients who believed that they had a ‘food allergy’ resolved when they were put on a ‘healthy eating’ diet for two weeks.) 
Meanwhile, as Dr Spence rightly points outs, the food industry has seen an opportunity and has moved in. But then that is what industries do; if they see a market for a product, they will supply that product, be it football shirts, top of the range sports cars or gluten-free food.
In this particular instance, the industry’s attention was originally attracted not by those who are self-prescribing a ‘freefrom’ diet but by the significant growth in diagnosed cases of coeliac disease (up from one in 300 to one in less than 100 and increasing daily) and in genuine food allergy (one in 70 children now have a peanut allergy). But there is no doubt that it is the numbers of those who are now choosing to eat ‘freefrom’ rather than those who have to do so that has fuelled the recent and dramatic growth in the industry.
On the other hand, all industries depend on their customers to buy their products and, given that ‘freefrom’ foods still remain significantly more expensive than conventional foods, they must be perceived to deliver some benefit to those who purchase them otherwise, in these straightened times, those purchasers would not continue to buy ‘freefrom’. Yet the upward trend in the purchase of ‘freefrom’ food shows no sign of slackening, nor do respected market forecasters such as Mintel, see any chance of it doing so anytime soon. 
So, Dr Spence, while you are condemning the food industry for peddling ‘bad medicine’ could the issue be rather different? Could it be that, far from being in the vanguard of scientific discovery and development, the medical fraternity is, yet again, trailing behind while the patient and the food industry lead the way?...
Since Dr Spence would no doubt dismiss my views as biased and ‘driven by profit’, let me declare my interest. For 20 odd years I have run totally independent magazines and websites (www.foodsmatter.com) providing information and support to those who suffer from food allergy, food intolerance and their many related health conditions. This information has included information on the foods available for those on ‘special diets’. These websites take a very small amount of advertising from industry but are in no way industry supported.
Six years ago we decided that awards might be helpful to encourage better quality, nutritional awareness and innovation in what had come to be known as the ‘freefrom’ industry. These awards (www.freefromfoodawards.co.uk) are ‘supported’ by the food industry in that we have sponsors and companies pay to enter however, all judging is entirely independent. During these six years the availability, range, quality and nutritional profile of ‘freefrom’ foods has improved enormously and we would hope that our awards have in some way contributed to this improvement.
Competing interests: I run independent informational websites supporting those with food allergy and intolerance and industry awards for 'freefrom' food.