Heightened allergy development in children has been linked to the antibacterial chemical triclosan — typically present in items such as toothpaste and certain cosmetics.
The connection has been described and rediscovered in the “Norwegian Environment and Childhood Asthma Study,” which in turn was conducted by the Norwegian Institute of Public Health. According to the findings, triclosan levels present in subjects’ urine were associated with elevated quantities of Immunoglobulin E and rhinitis. 623 urine samples were measured by the Center for Disease Control and Prevention in Atlanta; approximately 50 percent of the Norwegian participants (all of whom were 10 years in age) had identifiable levels of triclosan whereas 80 percent of American children had measurable levels.
According to the Norwegian Institute of Public Health: “Triclosan can change the bacterial flora on the skin, in the mouth and in the intestines. A change in the bacterial composition of "good" bacteria can cause an increased risk of developing allergies (hygiene hypothesis). Therefore, increased use of triclosan and antibacterial products has generally been associated with an increased incidence of allergies.”
Cosmetics accounted for 85 percent of the total amount of triclosan in Norway in 2001, whereas toothpaste claimed 75 percent. Moreover, “in the USA, where they have annual sampling and monitoring of chemical exposure, there is little evidence that exposure to triclosan is being reduced.”
These common facts about triclosan were noted by the study cohort for physicians and patients in both nations to consider:
- used to prevent bacterial growth
- does not work against all types of bacteria
- added mostly to cosmetic products such as toothpaste, deodorant and soap
- also added to kitchen utensils and textiles
- little triclosan is absorbed through the skin
- significant absorption through the mucous membranes in the mouth (toothpaste)
- has been in use for over 40 years in some products
- from animal experiments we know that triclosan acts to reinforce the development of Immunoglobulin (IgE) towards allergens
The study was fueled by a collaboration between the Norwegian Institute of Public Health, Oslo University Hospital and the National Institute of Health Sciences (NIEHS) in the US. The project was partly funded by the Research Council of Norway's program for Environmental Exposures and Health Outcomes.