Food Allergies: Types, Diagnosis, Treatments, and Prevention

Introduction

Food allergies have received considerable public attention in recent years, with some reports citing figures that alarm health experts. The most reliable statistics indicate that food allergies affect between 6 and 8% of children and nearly 4% of adults — and rates appear to be climbing (Howard, 2010, p. 122).

However, these numbers may be somewhat misleading. Many people who believe they have a food allergy may, in actuality, only have a food intolerance. A recent report published in the Journal of the American Medical Association found that, out of 1,200 studies on food allergies, the vast majority were inconclusive, incorrectly conducted, or deficient in some other manner (Riedl et al., 2010). According to Howard, "between 50 and 90% of people who think they have an allergy actually don't" (p. 122). Meanwhile, Riedl et al. note that many people mistakenly attribute nonspecific symptoms such as headaches and fatigue to food allergies, when those symptoms are in fact associated with food intolerance (2010).

Much of the confusion likely stems from the fact that most people do not know the difference between food allergies and food intolerances — or do not distinguish between the two. Although both conditions often share symptoms, there are key differences that set them apart.

Allergies: Descriptions and Types

A food allergy can produce a tingling or itchy sensation in and around the mouth, difficulty breathing, a swollen tongue or throat, hives, a sudden drop in blood pressure, vomiting, and diarrhea. Food intolerance, by contrast, usually results in bloating, abdominal pain, diarrhea, warmth, headaches, and tightness in the chest.

Diagnosing a food allergy versus a food intolerance can be accomplished through several methods. Common approaches include determining whether the person reacts every time a particular food is consumed, whether the reaction occurs regardless of the amount ingested, and a skin test to confirm the presence of an allergy. Nevertheless, according to one recent report, "food allergies and sensitivities account for approximately 60% of all undiagnosed conditions" (Russell & Wright, 2010, p. 47). Unidentified allergies and intolerances can contribute to a range of health problems, including asthma, enuresis, gastritis, recurrent headaches, canker sores, chronic lower back pain, and childhood ear infections. Some individuals also experience chronic fatigue, diarrhea, gas, bronchitis, and bladder infections as a result of foods they are intolerant of.

One report offered a particularly clear summary of the distinction: "the difference: food allergies are orchestrated by the body's immune system; food intolerance results from an inability of the gut to digest food normally" (Harvard Women's Health Watch, 2011, p. 4).

Among the most common food allergens are shellfish, peanuts, milk, and eggs. Common food intolerances include sulfites (as found in wine), MSG, and lactose, which is present in many dairy products.

When an allergenic food is consumed, the body's immune system treats it as a foreign threat. The immune system produces an antibody called immunoglobulin E (IgE), which attaches to the surface of immune cells located around blood vessels in the skin, stomach, and airways. When the offending food is detected again, the immune system triggers the release of chemicals that stimulate nerves and dilate blood vessels. In extreme cases, the entire system enters a state of overdrive — causing constricted airways, loss of consciousness, a dramatic drop in blood pressure, and even death.

Treatments

Immediate treatments for anaphylaxis — the severe systemic reaction described above — include a rapid injection of epinephrine and prompt medical attention from trained professionals. Longer-term treatment begins with a thorough diagnosis to determine whether reactions are being triggered by a food intolerance or a true food allergy.

The National Institute of Allergy and Infectious Diseases (NIAID) states that "there is currently no cure for food allergies, and the available treatments only ease the symptoms of a food-induced allergic reaction" (Food Allergy, 2011). This makes it especially important for affected individuals to know which foods they can and cannot safely consume. While no cure exists, treatment options do exist — though they are relatively limited in scope.

Beyond epinephrine injections, treatments include wearing medical alert bracelets to inform emergency responders of the condition, and developing a thorough understanding of the difference between food allergic reactions and food intolerances. Given the scarcity of treatment options, this condition is particularly dangerous for those who are unaware of their susceptibility to it.