Triclosan, a common ingredient used in toothpaste and other products formulations, could be increase risk of allergy development in children, according to a new study by researchers at Norwegian Institute of Public Health.

The investigators collected 623 urine samples and measured them at the Center for Disease Control and Prevention in Atlanta, US.

As per the study, it was found that approximately 50% of the Norwegian children had detectable levels of triclosan, while 80% of American children had measurable levels.

The children had approximately the same amounts of exposure.

The study found that elevevated levels of triclosan measured in urine were associated with increased levels of Immunoglobulin E (IgE) and rhinitis (blocked nose/hay fever) in 10 year-olds.

According to the study, the chemical has the possibilty to change the bacterial flora on the skin, in the mouth and in the intestines.

An alteration in the bacterial composition of ‘good’ bacteria can lead to an increased risk of developing allergies (hygiene hypothesis), thus the increased exposure to the chemical can be associated with an increased incidence of allergies.

A study in 2001 in Norway revealed that 85% of the total amount of triclosan came from cosmetic products, of which 75% were from toothpaste. Based on the study, that country removed triclosan from variety of products.

But the level to which Norwegian children are exposed to triclosan is not clear.

In the US, through the annual sampling and monitoring of chemical exposure, it was found that exposure to triclosan is being reduced.