Food allergies in American children seem to be on the rise, now affecting about 3 million kids, according to the first federal study of the problem.

Experts said that might be because parents are more aware and quicker to have their kids checked out by a doctor.

About 1 in 26 children had food allergies last year, the Centers for Disease Control and Prevention reported Wednesday. That's up from 1 in 29 kids in 1997.

The 18 percent increase is significant enough to be considered more than a statistical blip, said Amy Branum of the CDC, the study's lead author.

The CDC study was based on interviews with 9,500 families and did not yield state data, and the Utah Department of Health does not track the number of children in the state with allergies.

But according to the 2003 National Survey of Children's Health, the parents of 3.7 percent of Utah children age 17 and under had been told in the preceding year that their child had a food or digestive allergy.

Nobody knows for sure what's driving the national increase. A doubling in peanut allergies - noted in earlier studies - is one factor, some experts said. Also, children seems to be taking longer to outgrow milk and egg allergies than they did in decades past.

But also figuring into the equation are parents and doctors who are more likely to consider food as the trigger for symptoms like vomiting, skin rashes and breathing problems.

"A couple of decades ago, it was not uncommon to have kids sick all the time and we just said 'They have a weak stomach' or 'They're sickly,' " said Anne Munoz-Furlong, chief executive of the Food Allergy & Anaphylaxis Network, a Virginia-based advocacy organization.

Parents today are quicker to take their kids to specialists to check out the possibility of food allergies, said Munoz-Furlong, who founded the nonprofit in 1991.

In Salt Lake County, Michelle Fogg founded the Utah Food Allergy Network last year, and it has grown "like wildfire," she said. It has chapters in Davis and Tooele counties and is starting a new Utah county chapter.

It supports the proposed Food Allergy and Anaphylaxis Management Act, national legislation requiring the Secretary of Health and Human Services to develop a voluntary policy to manage risks of food allergy and anaphylaxis in schools.

"We get calls every year at this time from parents who are frustrated," Fogg said. "It's kind of all over the board in Utah."

The most complete policies include easy access to medications, options for teacher training and nut-free tables in lunchrooms, rather than isolating children to eat in classrooms, she said.

Earlier this year, Utah lawmakers passed House Bill 101, allowing Utah kids to carry epinephrine auto-injectors for reactions and providing for voluntary teacher training.

The new national study also found that the number of children hospitalized for food allergies was up. The number of hospital discharges jumped from about 2,600 a year in the late 1990s to more than 9,500 annually in recent years, the CDC results showed.

In Utah, 31 children under age one were hospitalized for allergic reactions in the five-year period from 2002 to 2006. Twelve children between ages 1 and 4 were hospitalized during the same period, and five children ages 5 to 9. Fewer than five children ages 10 to 14 were admitted, according to state health department data.

The CDC results came from an in-person, door-to-door survey in 2007 of the households of 9,500 U.S. children under age 18.

When asked if a child in the house had any kind of food allergy in the previous 12 months, about 4 percent said yes. The parents were not asked if a doctor had made the diagnosis, and no medical records were checked. Some parents may not know the difference between immune system-based food allergies and digestive disorders like lactose intolerance, so it's possible the study's findings are a bit off, Branum said.

However, the study's results mirror older national estimates that were extrapolated from smaller, more intensive studies, said Hugh Sampson, a food allergy researcher at the Mount Sinai School of medicine.

"This tells us those earlier extrapolations were fairly close," Sampson said.

The CDC study did not give a breakdown of which foods were to blame for the allergies. Other research suggests that about 1 in 40 Americans will have a milk allergy at some point in their lives, and 1 in 50 percent will be allergic to eggs. Most people outgrow these allergies in childhood.

About 1 in 50 are allergic to shellfish and nearly 1 in 100 react to peanuts, allergies that generally persist for a lifetime, according to Sampson.

Some people have more than one food allergy, he said, explaining why the overall food allergy prevalence is about 4 percent.

Children with food allergies also were more likely to have asthma, eczema and respiratory problems than kids without food allergies, the CDC study found, confirming previous research.

Also, Hispanic children had lower rates of food allergies than white or black children - the first such racial/ethnic breakdown in a national study.

The reason for that last finding may not be genetics, said Munoz-Furlong. She is Hispanic and said people in her own family have been unwilling to consider food allergies as the reason for children's illnesses. "It's a question of awareness," she said.