Soap and Toothpaste Raise Risk of Allergies in Kids

Soap, toothpaste may raise allergy risk in kids

If you have kids, you want to protect them from germs, so you probably use soap, toothpaste, and other products that contain antibacterial ingredients. However, that may not be such a good idea, according to a new study, because those antibacterial chemicals may make your kids at greater risk of allergies.

Why some health care products may cause allergies

The latest findings are from a study funded by the National Institutes of Health (NIH) and were the result of work conducted by researchers at Johns Hopkins Children's Center. Basically, the investigators found a link between children being exposed to antibacterial chemicals present in toothpaste, mouthwash, soaps, and other similar personal care products and the risk of developing allergies, although the scientists explained they are not suggesting antibacterials themselves cause allergies.

In fact, the findings of this NIH study are similar to those of a previous study conducted at the University of Michigan School of Public Health and reported in 2010. In that research, the authors found that the triclosan in antibacterial soaps, acne products, deodorants, and toothpastes had a negative impact on the immune system in kids.

In the University of Michigan study, the researchers said their findings "may support the 'hygiene hypothesis,' which maintains living in very clean and hygienic environments may impact our exposure to microorganisms that are beneficial for the development of the immune system." In layman's terms, people can be "too clean for their own good."

The Johns Hopkins study
Data from 860 children ages 6 to 18 were included in the study, in which the investigators evaluated the relationship between the amount of antibacterial products and preservatives from personal care products found in the children's urine with the level of IgE antibodies. IgE antibodies are chemicals the body produces in response to the presence of an irritant (allergen).

The Johns Hopkins researchers focused on seven ingredients known to have an impact on endocrine function in animals: triclosan (implicated in the previously mentioned study), bisphenol-A (BPA), benzophenone-3, and propyl, methyl, butyl, and ethyl parabens. Triclosan, propyl paraben, and butyl paraben were the only ingredients of the seven that were associated with an increased risk of allergy, and all three of these chemicals have antibacterial properties.


Triclosan is found in soaps, toothpaste, and mouthwash, while parabens are used in food, medications, and cosmetics. Here's a breakdown of what the researchers found:

  • Kids who had the highest levels of triclosan in their urine also had the greatest levels of food IgE antibodies.
  • Compared with kids who had the lowest levels of triclosan, those with the highest levels had almost twice the risk of environmental allergies
  • Kids who had the highest levels of parabens were the most likely to have detectable levels of IgE antibodies to pollen, pet danger, and other environmental allergens.
  • Children who had the highest levels of propyl paraben had a twofold increased risk of environmental allergy
  • On the positive side, high levels of parabens in the urine were not associated with an increased risk of food allergy

According to the senior investigator Corinne Keet, MD, MS, an allergist at Johns Hopkins Children's Center, "This finding highlights the antimicrobial properties of these agents as a probable driving force behind their effect on the immune system."

This study as well as previous ones suggest we are trying too hard to keep our kids clean. In addition to the University of Michigan study already mentioned, a study from the University of California, San Diego (UCSD) in 2009 noted that kids who are not exposed to bacteria that commonly appear on the skin have an increased susceptibility to certain diseases because they are not equipped to fight the microorganisms.

The UCSD study discovered that bacteria Staphylococci, which is commonly found in dirt and on the skin, can block a critical step needed for inflammation to occur. In 2002, a New England Journal of Medicine article stated that one important reason for the rise in allergic skin diseases could be the overuse of sanitizing practices, such as the use of antibacterial soaps, among young children.

Although parents want to keep their kids safe from infections, their preventive steps may have an unrealized cost. That cost may come in the form of an increased risk of allergies when kids use products such as soaps and toothpaste that contain antibacterial ingredients.

Savage JH et al. Urinary levels of triclosan and parabens are associated with aeroallergen and food sensitization. Journal of Allergy and Clinical Immunology 2012; doi: 10.1016/j.jaci.2012.05.006
Weiss ST. Eat dirt--the hygiene hypothesis and allergic diseases. New England Journal of Medicine 2002 Sep 19; 347(12): 930-31

Image: Wikimedia Commons