Words by James Tonin

While scientists are still struggling to explain it, new research seems to support what anecdotal evidence has been suggesting for years: food allergies are on the rise in North America, particularly in children. According to a 2010 article in The Globe and Mail, one in 13 Canadians has a food allergy which can be classified as serious. That represents nearly 8 percent of the population—an alarming number.

Researchers are divided in their opinions on the causes of rising food allergy rates. What factors might be behind this sudden spike in food allergies? Is there real cause for concern, or do food allergies add up to little more than medical smoke and mirrors?

Food Sensitivities vs. Food Allergies
Health Canada draws a sharp distinction between food sensitivity and a food allergy. According to the agency’s classifications, sensitivities result in discernible symptoms but do not involve the person’s immune system. Allergies, on the other hand, have the potential to be much more serious, since they trigger an immune system response which could cause reactions as severe as life-threatening anaphylaxis.
Given that self-reported rates are much higher than physician-reported rates, the seeming spike in food allergies could partially be explained by people mistaking sensitivities for allergies. Even so, this doesn’t explain the full story; hard data collected by various researchers does indeed indicate a definite rise in what Health Canada considers allergies.

Food Allergy Rates by the Numbers
Most people with food allergies have immune system responses to one or more of 10 so-called priority allergen foods. This list includes eggs, milk, mustard, peanuts, seafood, sesame, soy, sulphites, tree nuts and wheat. These foods account for more than 90 percent of all reported allergic reactions.

While food manufacturers are required by law to indicate whether or not their products contain any of these ingredients, even in trace amounts, allergy sufferers remain at constant risk of accidental ingestion.

Much of the most up-to-date research on food allergies is coming out of the United States, where rates and trends are comparable to those seen in Canada. According to a 2013 study released by the Centers for Disease Control and Prevention, the total number of food allergies in children rose by about half between 1997 and 2011. Childhood peanut allergies are estimated to have increased by some 300 percent between 1997 2008. Food allergies are also two to four times more likely to develop in children with underlying medical conditions such as asthma or allergies to non-food substances. Statistics like that cannot be explained by simple misclassification of self-reported symptoms.

While the majority of food allergies are detected and diagnosed during childhood, they can also appear at any age. In rare cases, a person who was once able to eat the food in question without any symptoms goes on to develop an allergy later in life—a phenomenon which completely mystifies researchers.

food4Other Possible Explanations
Researchers have put forward a number of hypotheses to explain the rapid and dramatic increase in food allergies. One of the most controversial of such theories is the so-called hygiene hypothesis, which posits that excessive attention to food cleanliness and sanitation is altering ordinary development of the immune system. In other words, our immune systems aren’t being exposed to enough germs, or enough different types of germs, to allow them to acquire necessary resistance capabilities. Supporters of this theory point to food allergy rates in developing countries, which are much lower while also having much lower sanitation standards.

Another explanation is related to the tendency in contemporary parenting to delay the introduction of foods with higher allergic potential. There is significant evidence that peanut allergy rates are much lower in regions where parents introduce these foods at an earlier age. Right now, a comprehensive, ongoing United Kingdom–based study known as the LEAP (Learning Early about Peanut Allergy) program is investigating this very possibility.

The third common explanation for the increase in food allergy rates is simply that there is greatly increased awareness of these issues among parents, doctors, pediatricians, educators and the general public. Thus, even minor symptoms are promptly reported and medically investigated. A related hypothesis suggests that advancements in detection technology have made it far easier for today’s doctors to diagnose food allergies than in the past.

As with all complex medical mysteries, the real answer is likely a combination of these and other factors. The increased awareness about food allergies has triggered a surge in research, so we should have more insights in the years ahead.

Detecting and Treating Food Allergies
Given that food allergies have no cure and, as of now, no explanation, early detection and careful management remain the best coping strategies. Parents are advised to exercise caution and vigilance when introducing foods on the priority allergen list. Symptoms of an allergic reaction include: difficulty breathing, swallowing or speaking; hives, rashes, red skin, itchy skin, and flushing of the skin; swelling of the face, eyes, lips, tongue, and/or throat; upset stomach, vomiting, and/or diarrhea; a rise in heart rate; a drop in blood pressure; or loss of consciousness.

If any of these symptoms occur, either to you or to your child, seek emergency medical attention. Once the allergic reaction has subsided, visit your family doctor to get a firm diagnosis and take extra caution to avoid all traces of the allergenic food in the future. One of the most frightening things about food allergies is that severe reactions can occur even with exposure to small amounts, and that a mild reaction the first time doesn’t guarantee a mild reaction the next.

In addition to specific natural foods, there’s a growing body of evidence that certain additives and preservatives also pose a risk of causing allergic reactions. These chemicals are typically found in processed and pre-packaged products, as well as fast foods and some types of takeout. Here’s a category-by-category breakdown of food additive allergy risks.

Flavour-Enhancing Additives
In an effort to reach the fabled “bliss point,” food manufacturers introduce chemical additives to alter or enhance the palatability of their products, or to change its nutritional content. Two of the most common examples of such additives are aspartame and monosodium glutamate (MSG).

Reactions to aspartame are rare, but can include swelling, hives, and rashes. MSG can cause headaches and unpleasant feelings of tightness in the upper body. There are also reports that MSG is linked to obesity, but results from studies are mixed.

The latest research indicates that approximately 2 percent of children and 1 percent of adults have allergic reactions to food preservatives, primarily from a class of chemicals known as sulphites. Two other classes of preservatives—parabens and benzoates—have also been linked to sensitivities.

These preservatives carry a risk of causing rashes, facial swelling, and asthma-like symptoms. In severe cases, these symptoms require emergency medical attention.

Testing and Managing Allergies to Additives and Preservatives
Unfortunately, it is not easy to test for allergies to specific additives and preservatives, and such reactions must be diagnosed through a process of elimination. Doctors recommend the same precautions used to introduce new foods to children: give small amounts of food and drink containing these chemicals, watch for possible reactions, and seek immediate medical attention if anything seems amiss.

James Tonin is a GTA-based yet globetrotting freelance writer. When he’s not contributing to Spirit of the City, you can find him flexing his brain by writing screenplays.