Industry bodies denounce claims that shampoo is unsafe
chemical commonly used as a preservative in a variety of cosmetic
products may damage unborn foetuses, saying that doses are far too
small to have such an effect.
The study, conducted on rats at the University of Pittsburgh, found that methylisothiazolinone (MIT) can affect the growth of parts of developing nerve cells, according to a recent presentation at the American Society for Cell Biology. The substance is used in cosmetics products such as shampoo and hand creams and its use is said to be extremely widespread in the industry.
Project leader Dr Elias Aizenman said of the findings in an interview with the BBC: "While more research is needed to determine what effect MIT would have in rodent models, both at the cellular level and to a developing nervous system, our results thus far suggest there is a potential that everyday exposure to the chemical could also be harmful to humans.
"I would be particularly concerned about occupational exposure in pregnant women and the possibility of risk to the foetus."
But industry bodies have reacted strongly to the scientists' findings, stating that MIT is a valuable chemical, which, when formulated properly helps to prevent a variety of harmful bacteria from forming in cosmetic products.
The US-based Cosmetic, Toiletry, and Fragrance Association (CTFA) said it could assure consumers that cosmetic products, including shampoos, were safe.
CTFA went on to state that the findings "lack a credible scientific basis in suggesting that MIT could be a safety issue for consumers using personal care products".
The association's statement went on to say: "In determining the safety of any ingredient, a major factor is exposure. Cosmetic exposure is so much lower than what is presented in this abstract as to make the study meaningless for safety evaluations purposes regarding cosmetic products."
Likewise, Colipa, the European Cosmetic, Toiletry and Perfumery Association has also spoken out to defend the industry's use of MIT. "Despite scare stories in the media claiming that the use of MIT as a preservative in cosmetics could harm the development of the nerve system in foetuses, consumers can rest assured that their cosmetic products, including shampoos, are safe," a Colipa statement said.
"The recent articles are based on a study carried out on a culture of isolated rat neural cells," the statement continued. "Whilst this is of academic interest it does not allow conclusions to be drawn regarding potential impact of MIT on human health. Under no circumstances can the results of this in-vitro study be extrapolated in-vivo."
Coplipa went on to point out that an independent expert scientific advisory committee recently published its opinion on the safety of MIT in cosmetic products under use conditions and concluded that it poses no risk of harm to consumers.
MIT has been approved by the US, Japan and the European Commission for use as a preservative in cosmetics. This regulation allows it to be used in very low levels, equal to one part per million. MIT was reviewed by the Cosmetic Ingredient Review in 1992 as a component of a preservative mixture and found to be safe for use in cosmetics.
The CTFA said that Dr Aizenman's experiments did not reflect the same levels of possible consumer exposure to this preservative through the use of regulated cosmetic products.
Dr Aizenman said he was most concerned by pregnant women who worked in factories and handling large amounts of MIT. He advised all regulatory bodies to be especially aware of this kind of industrial exposure, as it could have a detrimental effect on the unborn foetus. He also said that consumers' exposed to MIT through cosmetic products were at less of a risk.