Allergies

Food allergies affect about 4 percent of teens and adults, and up to 8 percent of children, mostly involving peanuts, tree nuts, soy, wheat, fish, or shellfish, but the actual number may be higher. Researchers estimate that for every case that is reported, two or three go unreported. The actual number is difficult to establish because the only way to absolutely determine if a person is allergic to a food is to feed it to them, and even in a clinical setting this can be life-threatening.

Researchers also do not agree on whether the incidence of food allergies is growing, but they do agree that children are exhibiting allergies to three or more foods more often than not, as compared to one or two foods in the past. According to the Food Allergy and Anaphylaxis Network (FAAN), the number of reported peanut allergies doubled from 1997 to 2002 in the United States. Hospitals in the United Kingdom are reporting more admissions for food allergies; whether this reflects increased awareness or increased incidence is not clear.