Another Person’s Poison by Matthew Smith
This scholarly new history of food allergy is not a straightforward read by any means, says Alex Gazzola, but it does give a lot of enlightening context to the arguments, controversies, problems and unknowns that still beset the subject today.
No doubt any number of anecdotes could have been chosen to illustrate the divisiveness that the subject of food allergy can generate, but it is that of the banning of peanuts at a Canadian sports stadium in the summer of 2009 with which Smith opts to open his book - specifically, concerning an AC/DC concert taking place at the venue. The decision was taken by the City of Edmonton, Alberta, after a mother wrote to explain of her peanut-allergic son’s anxiety about a possible dust cloud stirred up by thousands of feet treading upon discarded peanut shells.
Some AC/DC fans were unamused. “You can’t have an allergic reaction to the smell of peanuts”, “Sorry you’re allergic but enough already - the world isn’t turning only for you”, “I’m bringing peanuts in, and nobody can stop me” were among the responses. “Since when do you need peanuts to enjoy an AC/DC concert?” and “What if I smell your peanuts and die?” retorted the other side.
Not only do these polarised viewpoints perfectly set the tone for what follows, but in a sense they also immediately ask the reader to be tribal and pick a side. That choice may be a no-brainer for many of those who will be naturally drawn to this book, but you may find your sympathies and antipathies towards other characters who populate this history of allergy behaving more unpredictably as it unfolds.
Although Smith traces reactions to food - or ‘idiosyncracies’ - back two thousand years to Galen and Hippocrates, the real action kicks off in 1906 when Austrian paediatrician Clemens von Pirquet defined allergy as “any form of altered biological reactivity”. It was a broad definition, hampered by the limitations of what was known at the time, but it still casts its shadow on us today. What is a food allergy, or a food intolerance, or a food sensitivity? Consistent, agreed-upon answers remain elusive: we started off with a lack of clarity and certainty, and we have yet to fully remedy it.
From this somewhat vague springboard, the professional allergy ‘community’ soon splintered into three factions. The author calls them ‘orthodox allergists’, ‘food allergists’ and (later) ‘clinical ecologists’. Viewed through a political frame, the orthodox allergists could be perceived as the conservatives, the food allergists the socialists, the clinical ecologists the greens. The first viewed food allergy in narrow, essentially ‘anaphylactic’ terms, where science ruled, and dismissed other ‘sufferers’ as hypochondriacs; only large wheals and life-threatening reactions appeared to signify. The second were more patient focused and sympathetic - and suspected problem foods might be to blame for a broader spectrum of ill health. The third saw industrialisation and environmental pollution as the cause of illness, and harboured the ‘fringe’ element - one where alternative medicine and uncertain tests lurked. Definitions of allergy, as Smith says, “have historically been manipulated by allergists to suit their preconceived notions of what allergy is and is not”.
Skin prick tests served to further divide orthodox allergists and food allergists. False positives and negatives were possible and common, but SPTs did not help with ‘hidden’ or delayed allergies, towards which the orthodoxy held a dim view anyway. Food allergists were credulous - it surprised me to learn several had gone so far as to self-diagnose their own food allergies - and the orthodox sceptical. The discovery of IgE in the 60s offered potential for a truce: orthodox allergists liked that the marker was measurable, yet food allergists were dissatisfied that it was only a small part of the puzzle, and that non-IgE reactions and other sensitivities remained as elusive as before.
What I found most interesting was learning how the issues which concern us now, and which characterise the whole food hypersensitivity arena today, have been with us for far longer than one might expect. The culprits for the increase in food allergy - clean lifestyles / the hygiene hypothesis, vaccinations, dietary changes, pollution, upbringing - were being speculated on many decades ago. Smith tells of a food allergy and recipe book by a writer called Helen Morgan in which she claims “the numbers who are saying ‘I can’t eat that!’ are reaching into the millions” - it’s the sort of thing we hear today, but it was published in 1939, and covered such topically recognisable matters as sceptical doctors, poor food labelling, and judgmental peers who assume sufferers are on a diet.
Elimination diets, meanwhile, date back further, to the 1920s; some of the most popular being devised by California-based Dr Albert Rowe. In the 1930s, another allergist, Warren Vaughan, cemented the importance of family history in any food allergy diagnosis, writing that it “must be painstakingly obtained”. Even ‘free from’ foods - which are only fleetingly covered and which I very much wanted to know more about - were around at this time: they included Ditex Oat Crisps, which were made with oatmeal, cottonseed oil, soda, salt, sugar and ‘artificial flavours’, as well as the dairy-free milk substitutes Allerteen and Mull-Soy.
The book is a complex, sometimes challenging read: it is clearly the product of an academic, extensive references and all. There is a strong psychological undercurrent - not only in how individual patients’ symptoms - including asthma and skin reactions - were sometimes ascribed to the imagination or mental health issues - but also in how the tumultuous history of allergy mirrors that of psychiatry. I thought it a pity there wasn’t anything on genuinely somatised food reactions or much acknowledgment of the real role the emotions can play on the extent of an allergic reaction. Other omissions I was sorry about included the quirkier sensitivities (histamine, sulphates, nightshades) - although maybe there simply wasn’t much history to relate - and the more recent allergy developments (dermal sensitisation, gut microbiome, helminthic therapy, LEAP study), though perhaps time and a retrospective analysis is required to fairly understand their place in allergy’s history, if indeed they have one.
I don’t know the professional allergy community well enough to understand to what degree Smith’s trinity of specialists still exist today, but either way I think we need the best elements of all condensed into one unified coalition in order to move forward. Yes, we need the science and measurable markers of the orthodox allergists - but not their eye-rolling at the supposed hypochondriacs. Yes, we need the patient-centred approach of the food allergists - but with their credulousness somewhat tempered in this Dr Google age of self-diagnosis. And yes, we need to think more about how changes in our environment may have made us more reactive - not least, as Smith makes clear towards the end, about the former role of peanut-derived ingredients in vaccines - but we should lose discredited and fanciful food intolerance tests which some continue to market.
It is peanut allergies which thrust allergies back into the spotlight in the 80s, after a lull in previous decades, and the subject has yet to slip back behind the curtain. It’s still a great time to capitalise on this and address the many remaining questions that bedevil food allergy. I’m confident that current allergists see all this, but whether they can work together and reconcile any differences, and overcome the inherent complexity of the subject, remains to be seen. Until then, some division will remain. As will the scepticism. As the author puts it, “it is much easier to dismiss the gastrointestinal complaints of a middle-aged woman than it is to question a child with a severe anaphylactic allergy to peanuts”.