Allergic children are being exposed to peanuts at much earlier ages despite warnings from health experts, a trend that may contribute to the development of peanut allergies, researchers say.

Though it's recommended that families avoid exposing their children to peanuts in the first three years of their life to avoid peanut allergies, that's not happening, new research suggests. 

A study of 70 children born between 2000 and 2005 and conducted by researchers at Children's Hospital of Pittsburgh found that children who are allergic to peanuts were on average first exposed to them at the age of 14 months and developed a reaction at 18 months.

Conversely, researchers found that in a study of 70 patients born between 1988 and 1999, the median age of exposure to peanuts among kids was 19 months, with onset of the allergy at 21 months.

"The decline in the age of first peanut reaction seems to be attributable to earlier exposure," reads the study.

The researchers also discovered that children born after 2000 were also more likely to be allergic to other foods as well, such as eggs, cow milk and fish.

The study is published in the December issue of Pediatrics, the journal of the American Academy of Pediatrics. The data was based on files of patients of the Duke University pediatric allergy and immunology clinic.

The researchers say that further study is underway to determine whether delaying a child's exposure to peanuts can actually reduce the risk of an allergy.

Peanut allergies among U.S. children increased from 0.4 per cent to 0.8 per cent between 1997 and 2002, according to research cited in the study.