Are food allergies really increasing? Or is it a case of increased awareness? Both, according to allergist and immunologist Stefano Luccioli, MD. “Over the past 10 years, studies have shown a doubling in the prevalence of peanut allergies and an 18 percent increase in reported food-allergy prevalence in children,” he says. But accurate estimates remain elusive, primarily because confusion persists about the definition of food allergy. Doctors use various blood tests to attempt to pin down a suspected allergy, but test-usage standards remain unclear and results are sometimes misunderstood. Currently, the National Institute of Allergy and Infectious Diseases is crafting a formal definition for food allergy, plus guidelines to diagnose and manage patients.

Meanwhile, although it seems clear that food-related reactions are escalating, no one theory accounts for it. One popular explanation is the hygiene hypothesis, which holds that our too-clean society prevents the immune system from managing a wide variety of microorganisms, so it interprets food proteins as invaders. A second theory relates to food exposure, suggesting, for example, that avoidance of certain foods at an early age may increase allergic potential, says Lucy Gibney, MD, emergency physician and mother of a child with severe food allergies. The American Academy of Pediatrics now recommend that parents introduce solid foods of all kinds to babies after 4 to 6 months of age; however, says Robert Rountree, MD, Delicious Living’s medical editor, “this flies in the face of data showing that infants tend to have a ‘leaky’ intestinal wall that does not provide good barrier function against food antigens—thus making at-risk infants [because of family allergy history] more vulnerable if they are introduced too early.” Check with your doctor; and, “when introducing solid foods for infants, try one at a time over several days so you can associate any new symptoms correctly,” says Gibney.