A new study suggests that food allergies affect more children than government health officials estimate.

The advocacy group-funded study in the journal Pediatrics says one in 13 children in the U.S. has some type of food allergy, and researchers say 40 percent of those children suffer severe reactions. Typical signs of a true food allergy include skin rashes, wheezing, tightness in the throat or difficulty breathing.

In the study of more than 40,000 children, 8 percent had food allergies, and peanuts and milk were the most common sources.

The most recent estimate from the Centers for Disease Control and Prevention found that about 3 million children had food allergies. Figures from this new study translate to nearly 6 million children. Dr. Calman Prussin, an investigator with the National Institute of Allergy and Infectious Diseases, says that figure "confirms that food allergy is a substantial public health problem."

Copyright 2013 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.