Food allergies a growing concern

Dr. Conway McLean

Although it may strike you as hyperbole, there is a new epidemic in the land. Most every time this topic is researched, the “E” word, as in “epidemic,”appears. All the news sources agree: this is a subject of growing concern. But then, this is the basic concept of an epidemic: not that some new disease is deadly, but only that it is of increasing incidence, becoming a more common problem. This one is not a trivial concern, but very capable of striking suddenly, without warning, resulting in death.

If one were to have researched the subject of children’s health issues a century ago, the primary topics would have been concerning diptheria, or perhaps cholera. But these threats to children have largely been vanquished due to the development of antibiotics and improved sanitation. Instead, the increase in the number of people with food allergies must be described as explosive, having become a huge problem, and responsible for emergency room visits at an ever-increasing rate.

Too often in those afflicted, peanuts produce an anaphylactic reaction. This is a severe, whole-body allergic reaction to some chemical that has come to stimulate a person’s immune system. This chemical is called an allergen, although there are many different ways this material can enter the body. They include inhalation, injection (think of insect venom or a shot of penicillin), or via simple contact with the skin. Ingestion is another means for an allergen to enter the body.

After being exposed to a substance, for example a bee sting, the person’s immune system becomes sensitized to it. When the individual is again exposed to that allergen, an allergic reaction will typically occur. Thus, food allergies are simply an overreaction by the immune system to a foreign substance. The anaphylactic reaction happens quickly after exposure and involves the whole body. Histamine, a substance produced by many tissues in the body, has many effects, one of them being a tightening, aka constriction, of the airways. Swelling of the face and throat are also common. Because of this restriction of the throat, the airway may become closed, and death can result.

Of all the food allergies, this allergic reaction to peanuts is getting the greatest attention. Reports of these allergies more than tripled in one ten year span. Emergency room visits due to food allergies in general increased nearly that much in just a 4-year period. The prevalence of peanut allergy among children in the United States has risen more than threefold, from 0.4 percent in 1997, to 1.4 percent in 2010. Many people with an allergy to peanuts are also allergic to one or more of the other types of nuts (eg walnuts, pecans or almonds).

Exact data about this problem is difficult to produce. Before 1980, peanut allergies were rarely mentioned in the media or in medical literature. Around 1990, scientific and medical articles began discussing the seriousness of peanut allergies. Unfortunately, prior to the ’90s we had little data on peanut allergies. And those numbers were generally based on self-reporting. This is not considered a reliable source of data, leaving the data open to interpretation, and influenced by increased media attention. We just don’t have a good sense of the changes over a longer period of time.

Peanut allergies in particular have become a nightmare for parents. When a child is allergic to nuts, everything the child eats must be closely monitored, both in and out of the home. Peanuts, peanut butter, and peanut products in general, are ubiquitous, found in dishes you might never expect. Many cuisines use them aplenty, especially Asian and Mexican dishes, many baked goods, even many candies contain some small quantity.

Can such an increase be due to simple biology or could it be because of greater recognition of the condition? If it is due to the former, it is critical we determine the cause. Could it be some change in the environment? There are many aspects of life in the developed nations (especially their cities), where allergies are far more prevalent than in rural countries, that is obviously different. Some prime examples would be China and Africa. One possibility that has been proposed as being a possible cause is air pollution. Researchers have found a strong correlation between pollutants, such as diesel exhaust and cigarette smoke, and the development of allergies. But this is clearly not the whole story, since allergies have continued to climb while smoking and air-pollution rates have fallen of late.

And do not confuse food allergies with the condition known as food intolerance. This occurs when people who lack an enzyme for digesting dairy products suffer intestinal problems. The individual is not allergic to milk, but simply can’t break down milk proteins sufficiently. With so many acutely aware of the presence of food allergies, some will assume it is, and thus a potentially life-threatening condition.

At this time, we have no cure, no treatment, which will end the hypersensitivity. Several preliminary studies suggest we may be able to dampen the reaction with immunotherapy. As allergists give shots for pollen allergies, we utilize this concept by exposing an individual to minuscule amounts of the offending substance, like a peanut protein. This is followed by the administration of gradually increasing amounts of the offending substance. This is always done under strict medical supervision.

There is no question that our awareness of the presence of food allergies has increased. Laws requiring labeling have helped. Numerous educational initiatives, as well as prevention education, have all contributed to the greater awareness of this type of allergy among patients and providers. This increased awareness leads more people to attribute a variety of symptoms to food allergy without seeking confirmation. This is the danger of counting on self-reporting for data. People are inaccurate and inconsistent.

Due to the increasing incidence of food allergies, and especially peanut allergies, it is essential that we find the cause and intervene. A significant problem is that we are still not sure whether the increases are due to changes in recognition or is there some other environmental influence. But when you get down to it, the bigger dilemma is the inherent difficulty in determining the prevalence of food allergies in actual, real-world population groups. Definitive classification of food allergy requires an oral food challenge, which is difficult to perform on a population level. So we remain in ignorance as to why food allergy is increasing, and, once again, treating the symptom and not the cause.

Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula, with a move of his Marquette office to the downtown area. McLean has lectured internationally on wound care and surgery, being double board certified in surgery, and also in wound care. He has a sub-specialty in foot-ankle orthotics. Dr. McLean welcomes questions or comments