A new study led by the University of Reading in the UK that examined breast tissue samples from 40 women who underwent mastectomies for breast cancer, found they contained widespread traces of parabens, preservatives commonly used in deodorants, make-up, body lotions, moisturisers and many other cosmetic products. Although the study does not prove that parabens cause or even contribute to the development of breast cancer, it raises questions about their use.

Dr Philippa Darbre, of Reading’s School of Biological Sciences led the study, a report on which appears in the 12 January online issue of the Journal of Applied Toxicology.

She told the press:

“These results are of concern because parabens have been shown to mimic the action of the female hormone oestrogen and oestrogen can drive the growth of human breast tumours.”

Darbre has been studying parabens and their effect when absorbed via the skin for more than ten years. In 2004 she published a smaller similar study that measured levels of parabens in tissue samples from 20 human breast tumors.

For this study, Darbre and colleagues examined a total of 160 tissue samples, four from each of 40 women who had had mastectomies for primary breast cancer in England between 2005 and 2008. In each patient, the samples came from four different serial locations from the axilla (nearest the armpit) to the sternum (breast bone).

158 of the 160 samples (99%) contained at least one parabens, and 96 of them (60%) contained five of them.

It was not possible to identify the source of the parabens in each case, but since seven of the women said they had never used antiperspirant-deodorant products, the researchers suggest this means the compounds entered the breast from other sources.

Darbre said:

“Many of the concentrations of the parabens measured in these breast tissues would be sufficient to drive the growth of oestrogen-dependent human breast cancer cells in the laboratory.”

But she cautioned that the fact they detected the compounds in the majority of the samples does not mean we can assume they actually caused breast cancer in the participants.

“However,” she said, “the fact that parabens were present in so many of the breast tissue samples does justify further investigation.”

Written by Catharine Paddock PhD