This about-face is partly due to the fact that food allergies have become so common. According to the Centers for Disease Control and Prevention, their prevalence rose nearly 20 percent between 1997 and 2007, and it now strikes up to 8 percent of children under the age of 4. (The numbers are greatest among young kids, since allergies are often outgrown.) That means your children are more likely than you were to have classmates with allergies--or to have one themselves.
Food allergies have become such a public issue that parents sometimes feel a backlash when schools and daycares declare themselves "nut-free." (Nut allergies are particularly feared because they tend to produce the most life-threatening reactions.) A doctor from Harvard Medical School touched a nerve in 2008 when he wrote a medical-journal article titled "This Allergies Hysteria Is Just Nuts," after a school bus was evacuated because someone spotted a peanut on the floor. "I understand the world can't necessarily revolve around kids who have allergies," says mom Kathryn Francis. "But if any parent sat down long enough to think 'What if that were my child?' I think they would understand why schools at least need to have a discussion about this."
THEN: Parents were warned to hold off on introducing certain foods. To help prevent allergies, pediatricians used to advise families with a history of them to delay giving their children eggs until age 2--and to avoid peanuts, tree nuts, and fish until their kids turned 3. The thinking was that a child's immune system needed to be more mature before dealing with allergy-prone foods.
NOW: That advice is gone. In 2008, the American Academy of Pediatrics withdrew its recommendation to delay these foods. "The change was based on a lack of evidence that waiting for these long periods protects against allergies," says Scott Sicherer, M.D., a professor of pediatrics at Mount Sinai School of Medicine's Jaffe Food Allergy Institute, in New York City.
Some experts believe that withholding allergenic foods may make children more likely to develop adverse reactions.
In fact, some experts believe that withholding allergenic foods may make children more likely to develop adverse reactions. A study that compared the prevalence of allergies among Jewish children in Great Britain (where peanuts are rarely given to infants) to children in Israel (who tend to eat them before their first birthday) found that the Israeli kids had about one tenth the risk as their nut-averse counterparts. Other research has bolstered the idea that early exposure may reduce a kid's odds of becoming allergic. Experts aren't sure why, but some evidence suggests there may be a time in a child's life--not too early, not too late--when the immune system best tolerates certain foods.