No evidence that parabens in cosmetics cause 99% of cancers

A Facebook post, which has now been deleted but was widely shared, claimed: “99% of cancer is caused by parabens (toxins) found in most beauty products, skin products & home fragrance”.

This may be based on a study which found 99% of breast cancer tumours contained parabens, but which explicitly said this couldn’t be used to claim parabens were the cause. 

Some recent evidence has emerged that parabens may increase the growth of a breast-cancer cell line found in women with West African ancestry.

However, there is no evidence that the chemicals cause 99% of cancers. 

What are parabens?

Parabens are chemicals which are widely used as preservatives in cosmetics, toiletries and other products, including food. They work by preventing the growth of microorganisms like bacteria and fungi.

The European Scientific Committee on Consumer Safety allows specific parabens which have undergone stringent safety tests to be used in low levels in cosmetics. Some parabens which have not been properly evaluated for human risk are currently banned by the EU, with others which have been evaluated allowed only at specific concentrations or in specific products.

The use of parabens in cosmetics is not currently regulated in the United States.

Parabens do not cause 99% of cancer

Parabens can be absorbed through the skin, and most people will have been exposed to them in some way. 

Research has been conducted about a possible relationship between parabens and breast cancer cell growth. But studies have found no causal link between the chemicals and cancer.

A 2004 study found traces of intact parabens in some breast cancer tumour samples, but it did not find a causal link between parabens and the development of breast cancer.

A subsequent study published in 2012 by the same author found that of 160 tissue samples collected from 40 women who had undergone mastectomies for first primary breast cancer, 99% of them contained at least one paraben.

This study appears to be referenced in the comments of the Facebook post, and may be what the user was referring to in her claim that “99% of cancer is caused by parabens”.

However, this is an inaccurate interpretation of the findings, which did not prove any causal link between parabens and breast cancer, with the study author herself cautioning that the study’s findings “cannot be taken to imply that [parabens] actually caused breast cancer in the 40 women studied.”

Some studies have found that parabens might mimic the hormone oestrogen, which itself has been linked to breast cancer. More recently, researchers at the City of Hope cancer centre in Los Angeles presented findings from in vitro cell testing which they said showed that parabens increased the growth of a breast cancer cell line found in people with West African ancestry, but not in a white breast cancer cell line, and promoted the spread of breast cancer cells in both, with a bigger effect seen in the West African cell line.

This study has not yet been published, with Dr. Xiaoting Zhang, director of the Breast Cancer Research Program at the University of Cincinnati College of Medicine, who was not part of the study, telling Medical News Today that while the findings were “intriguing” further studies were needed, and that we should be “cautious in drawing the conclusion” that parabens could potentially increase the risk of breast cancer in West African women.

According to the American Cancer Society, the oestrogen-like properties of parabens are far weaker than natural oestrogen, which is synthesised in both men and women and is more likely to be linked to the development of breast cancer.

The US Food and Drug Administration says: “At this time, we do not have information showing that parabens as they are used in cosmetics have an effect on human health.”

Image courtesy of Naty Melnychuk