Common Chemicals That Trigger Allergies

Scientists are learning that chemicals you encounter every day can interfere with your immune system, leading to allergies and other problems.

By Emily Main


Sneezing a bit more than you used to? Are you one of those people who “always gets sick”? It may have something to do with your toothpaste. A recent study published in Environmental Health Perspectives found that common chemicals such as triclosan, an antibacterial chemical used in toothpastes and other personal-care products, and bisphenol-A (BPA), used in plastics and the linings of food cans, could be interfering with our immune systems.

Knowing that BPA and triclosan both interfere with the endocrine system and act like estrogen in the body, the authors suspected that because estrogen protects immune cells, the chemicals could have some impact on the health of the immune system. Previous laboratory studies have also shown that BPA and triclosan, along with a few other endocrine-disrupting chemicals, increase production of cells that lead to allergy development.

The authors used data from the 2003 to 2006 National Health and Nutrition Examination Surveys, surveys conducted annually by the Centers for Disease Control and Prevention that measure the levels of chemicals and various health markers in a representative sampling of the U.S. public. The researchers compared levels of BPA and triclosan in roughly 5,000 participants' urine samples with two markers of immune-system health: a professional diagnosis of allergies or hayfever and levels of antibodies for cytomegalovirus, a common virus that most people contract at a very young age and that stays in our bodies for the rest of our lives. “Controlling this virus becomes a top priority for the immune system, and high antibody levels signal that the immune system is less effective at controlling it,” says Erin Rees Clayton, Ph.D., research investigator at the University of Michigan School of Public Health and one of the study’s coauthors.

Triclosan was significantly associated with allergies and hayfever, their analysis showed. That finding supports the “hygiene hypothesis,” or the idea that the more we try to sanitize our homes and our environments, the less able our immune systems are to defend us against common “invaders” like allergens and pollen. Although BPA wasn’t found to have an impact on allergies, it did seem to affect those cytomegalovirus antibodies. Adults over 18 who had higher levels of BPA also had higher levels of antibodies, suggesting that their immune systems weren’t functioning as well as they should be.