“Contains peanuts.” “Lactose intolerant.” “Gluten free.” “Contains shellfish.” These and many phrases like them would have made absolutely no sense a hundred years ago. Food allergies were profoundly uncommon long before the Department of Agriculture and the Federal Food and Drug Administration (within the Department of Health and Human Services) took responsibility for quality in the foods we eat. Basically unheard of. Yet these warning phrases are increasingly common in our daily vocabulary, ranging from labels on food packaging to admonitions on simple restaurant menus. What’s worse, some of these allergies can cause serious reactions, even death.
What is equally interesting is the continued lack of food allergies as a major issue in developing and under-developed nations. Is that because of a lack of food variety, food processing or simply because there are so many other medical issues in such regions? Or do people in regions with parasites and bacteria normally in their food chain simply develop biological coping mechanisms? Are our developed world hygiene standards, perhaps, to blame? For those who track these trends, it does seem that food allergies are a developed nation issue… witnessing huge increases in the developed world over the past three decades.
Bill Hathaway, writing for the January 14th edition of YaleNews, examines the impact of a recent Yale study by the Department of Immunology, published on the same day in the scientific publication Cell, entitled Food allergy as a biological food quality control system, by Yale researchers Esther Florscheim, Zuri Sullivan, William Khoury-Hanold and Ruslan Medzhitov:
“For instance, as many as 8% of children in the U.S. now experience potentially lethal immune system responses to such foods as milk, tree nuts, fish, and shellfish. But scientists have struggled to explain why that is… A prevailing theory has been that food allergies arise because of an absence of natural pathogens such as parasites in the modern environment, which in turn makes the part of the immune system that evolved to deal with such natural threats hypersensitive to certain foods.
“[The four] Yale immunobiologists propose an expanded explanation for the rise of food allergies — the exaggerated activation of our internal food quality control system, a complex and highly evolved biological mechanism designed to prevent us from eating harmful foods. The presence of unnatural substances, including processed food, or environmental chemicals, such as dishwashing detergent, in the modern environment, as well as the absence of natural microbial exposure, play a role in disrupting this control system, they argue.
“The theory can lay the groundwork for future treatment or prevention of food allergies, the scientists suggest… ‘We can’t devise ways to prevent or treat food allergies until we fully understand underlying biology,’ said co-author Ruslan Medzhitov, Sterling Professor of Immunobiology and investigator for the Howard Hughes Medical Institute. ‘You can’t be a good car mechanic if you don’t know how a normal car works.’
“The quality food control system present in the biology of all animals includes sensory guardians — if something smells or tastes bad, we don’t eat it. And there are sentinels in the gut — if we consume toxins, they are detected and expelled. In the latter case, a part of the immune system as well as the parasympathetic arm of the nervous system also mobilize to help neutralize the threat.
“This type of immune system response triggers allergies, including food allergies, a fact that gave rise to the so-called ‘hygiene hypothesis’ of food allergies. The lack of natural threats such as parasites made this portion of the immune system hypersensitive and more likely to respond to generally innocuous proteins found in certain food groups, the theory holds. This helped explain why people living in rural areas of the world are much less likely to develop food allergies than those living in more urban areas.
“However, food allergies have continued to rise dramatically long after elimination of parasites in the developed world, Medzhitov noted. So the Yale team now theorizes that other environmental factors influenced activity within the natural food quality control system and contributed to immune system hypersensitivity to certain food allergens.
“‘One factor is increased use of hygiene products and overuse of antibiotics and, secondly, a change in diet and the increased consumption of processed food with reduced exposure to naturally grown food and changed composition of the gut microbiome,’ Medzhitov said. ‘Finally, the introduction of food preservatives and environmental chemicals such as dishwashing detergents introduced novel elements for immune systems to monitor.’ Collectively, these changes in the environment effectively trigger food quality control responses making the immune system react to food proteins the way it would react to toxic substances, the team argues… ‘It’s guilt by association,’ Medzhitov said.
In the end, the advances in modern standards of health and cleanliness have some definite drawbacks, and we just might need more of those advances to fix what is not a problem in the Third World!
I’m Peter Dekom, and as climate change and the rapid transmission of disease suggest, modern advancements carry many massive threats to life that did not exist in simpler times.
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