Consumers are voting with their purses and shunning products containing parabens, but should you worry if they’re in your skincare products? Dr Haran Sivapalan examines the evidence.
Both these articles were reporting research into a possible link between parabens, an ingredient of many cosmetics, and the development of breast cancer. Not surprisingly consumers were spooked and, as a result, there’s a growing market for ‘paraben free’ alternatives.
But with around 80% of products on the market still including them in the ingredients list – should we be worried? Or, was this merely an instance of media hyperbole?
What are parabens?
Parabens are a group of chemicals derived from benzoic acid – often found in berries. First used in the 1920s as preservatives for certain drugs, today they are added to cosmetics in order to prolong their shelf life. In addition to being good preservatives, parabens are cheap to produce, have anti-bacterial and anti-fungal properties, are chemically stable and do not alter the colour or consistency of the product. It’s no wonder then, that parabens are widely used in cosmetic goods. In fact, aside from water, they are the most common ingredient found in cosmetics.
Shampoos, conditioners, moisturising creams, deodorants, makeup foundation – these are all quite likely to contain parabens. If you look at their list of ingredients, you may spot one or more of the following types of paraben: methylparaben, n-butylparaben, ethylparaben, n-propylparaben and isobutylparaben.
How are we exposed to parabens?
While parabens are able to enter the body through ingestion (eating or drinking contaminated foodstuffs or tap water) and inhalation (of dust and indoor air), the application of cosmetics to the skin is by the far the dominant route of entry. One study suggests that through the daily use of cosmetics, the average person is exposed, per day, to 2.4 mg of parabens per kilogram of bodyweight.
After penetrating the skin however, parabens are mostly metabolised and excreted in the urine. But evidence suggests that this process isn’t 100% effective with studies finding unmetabolised parabens present in the bloodstream and urine after topical cosmetics were applied to the skin. This intimates that at least some parabens are capable of escaping breakdown by the body. If these free, unmetabolised parabens were biologically active, thereby interfering with the body’s normal functions, they could potentially pose health problems.
The issue with these studies, however, is that they tested doses of parabens at higher concentrations than those contained in everyday cosmetics. Also, when you consider that many people use products such as moisturising creams very regularly (e.g. daily), it’s apparent that studies haven’t thoroughly examined the effects of long-term, repeated application of cosmetics to the skin. So, what we don’t know is exactly how much unmetabolized paraben remains in our body in real life, and further research is needed to establish that accurately.
Why are people worried about parabens?
Some initial studies on rats suggested that unmetabolised parabens were “weakly oestrogenic”. That is, they can mimic the effects of oestrogen – the sex hormone responsible for, among several other things, the regulation of the female reproductive system and the development of secondary sexual characteristics. This posed a question – could parabens interfere with any of the body’s functions normally regulated by oestrogen?
On a molecular basis, parabens mimic the effects of oestrogen by binding to the oestrogen receptor. This raised concerns, as the very same oestrogen receptors are often present on cells within the breast tissue. When oestrogen binds to these receptors in high concentrations, it can stimulate the uncontrolled growth of the cells. This, in turn, can lead to breast cancer. A second question arises then: could parabens, by mimicking oestrogen and binding to the oestrogen receptor, significantly increase the risk of breast cancer?
In 2004, Dr. Phillippa Darbre and colleagues found traces of unmetabolised parabens in samples of breast cancer tissue. Then in 2012, along with Barr and colleagues, Dr. Darbre found parabens in breast cancer tissue received from women who had undergone mastectomy. These findings prompted a swathe of media headlines implicating parabens (particularly those in deodorants) in the development of breast cancer. Of course, as is often the case in media reports of scientific findings, the story is far less clear-cut.
Should we be worried about parabens in cosmetics?
When it comes to mimicking the effects of oestrogen, it is important to stress that parabens are only weakly oestrogenic. For example, parabens do not bind to oestrogen receptors with the same affinity as oestrogen. Oestrogen naturally produced by the body is therefore likely to overwhelm any of the oestrogenic effects elicited by parabens. Similarly, oestrogens initiate a whole host of complex chemical and genetic changes in the body. Only a small proportion of these changes are mimicked by parabens. Exposure to the parabens contained within cosmetics then, is hardly the same as pumping your body full of the real thing.
The small dose of parabens within common cosmetics is also probably too low to cause any harm. A review of animal studies published in the journal Environmental International (2014) reported no strong evidence of adverse health effects; and that was using very high doses of parabens, at 100 – 1000 mg per kg bodyweight per day. When you consider that the exposure to parabens from cosmetic products is estimated to be far below this, at 2.4 mg per kg bodyweight per day, the risks seem fairly low. Indeed, studies have not reported any negative health effects when using the estimated dose of 2.4 mg/kg of body weight per day.
And what about breast cancer? While Darbre’s 2012 study did show parabens to be present in breast tumours, it would be a massive leap of logic to conclude that parabens cause breast tumours. In fact, as breast cancers have rich blood supplies, it is perhaps unsurprising that parabens, which have entered the bloodstream, might end up in breast tissue.
Darbre’s 2012 study also had major limitations. Firstly, the study was only conducted on tumour samples from 40 women; it was by no means a large, high statistically-powered study. Moreover, the study did not compare the samples of cancerous breast tissue to samples of breast tissue from healthy controls. Given these weaknesses, the study certainly cannot be taken as overwhelming evidence for parabens as a cause of breast cancer.
Further research required
A few in vitro studies (experiments not conducted within a living animal or human) point to a role of parabens in promoting the growth or ‘proliferation’ of cells. Although, the uncontrolled growth of cells is central to the development of cancer, much more research is needed in this area before anything firm can be concluded.
What is the verdict on parabens?
In 2005, the Scientific Committee on Consumer Safety (a body that advises the European Union on health risks) reviewed the evidence on parabens and came to the following conclusion:
“According to current knowledge, there is no evidence of a demonstrable risk for the development of breast cancer…”
As of September 2016, the FDA or Food and Drug Administration (a public health body in the USA) reached similar judgement:
“At this time, we do not have information showing that parabens as they are used in cosmetics have an effect on human health”
And what does the law say? Currently the European Union allows a maximum concentration of 0.4% of a single paraben (e.g. ethylparaben) in a cosmetic product and a maximum of 0.8% for all types of paraben combined. While not enshrined in law, the governments of USA and Canada recommend similar doses of parabens.
In 2011, an updated report by the Europe’s Scientific Committee on Consumer Safety suggested further limiting the concentrations of butylparaben and methylparaben to 0.19% per cosmetic product. The reason for this change arose from the previous paraben limits being based on studies in rats. Compared to humans, rats metabolise parabens in the skin much more effectively. The effect of this is that slightly more unmetabolised paraben probably enters the human body via the skin than previously thought. Nevertheless, the new cap of 0.19% methyl- and butyl-paraben per cosmetic product has not been passed into legislation.
Despite still being able to include them in products many manufacturers are heeding consumer’s concerns and reformulating products to be paraben free. So, if you are concerned, these days there are plenty of alternatives available.
Barr, L., et al (2012). Measurement of paraben concentrations in human breast tissue at serial locations across the breast from axilla to sternum. Journal of Applied Toxicology, 32(3), 219-232. http://onlinelibrary.wiley.com/doi/10.1002/jat.1786/abstract
Błędzka, D., Gromadzińska, J., & Wąsowicz, W. (2014). Parabens. From environmental studies to human health. Environment international, 67, 27-42. https://www.ncbi.nlm.nih.gov/pubmed/24657492
Daily Mail (2004). Deodorants linked to cancer. Available online at: http://www.dailymail.co.uk/health/article-205705/Deodorants-linked-cancer.html
Darbre, P. D., & Harvey, P. W. (2008). Paraben esters: review of recent studies of endocrine toxicity, absorption, esterase and human exposure, and discussion of potential human health risks. Journal of applied toxicology, 28(5), 561-578. https://www.ncbi.nlm.nih.gov/pubmed/18484575
Darbre, P. et al. (2004). Concentrations of parabens in human breast tumours. Journal of applied toxicology, 24(1), 5-13. https://www.ncbi.nlm.nih.gov/pubmed/14745841
FDA (2016). Parabens in cosmetics. Available online at: http://www.fda.gov/cosmetics/productsingredients/ingredients/ucm128042.htm
Scientific Committee on Consumer Safety (2011). Opinion on Parabens. Avaialble online at: http://ec.europa.eu/health//sites/health/files/scientific_committees/consumer_safety/docs/sccs_o_041.pdf
The Sun (2012). Breast cancer risk all over shops’ shelves. Available online at: https://www.thesun.co.uk/archives/news/297767/breast-cancer-risk-all-over-shops-shelves/