For years, we've been hearing that more children are suffering from food allergies. Some estimates say allergy to peanuts in particular have as much as doubled or tripled in the past decade. 

A new study from federal researchers offers the latest, albeit lower, estimate. Food allergy among children increased 19 percent between 1997 and 2007, they found. In 2007, about 4 percent of all children had a food or digestive allergy.

Between 1993 and 2007, the number of visits to clinicians for allergies tripled. Hospitalizations increased, too. In the period between 1998 and 2000 and 2004 and 2006, hospitalizations rose from an average of 2,600 to 9,500.

The research, published in the new issue of the journal Pediatrics, is based on a review of several federal surveys, such as hospital discharge data and interviews with parents of children with allergies. Researchers with the CDC's National Center for Health Statistics also looked at estimates of child food allergies by race and gender. They found that black children were twice as likely as whites to have peanut allergy and nearly twice as likely to be allergic to milk.

The study examines levels of a particular antibody, known as immunoglobulin E, or IgE. Children with higher IgE levels appeared more susceptible to allergies. Some 9 percent of children had detectable levels of IgE to peanuts, the study found.

The bottom line: food allergies are increasing for boys, girls and children of all ages and ethnicities. But how much of this is a real increase and how much is due to closer detection and increased awareness remains murky.