talc cancer myth

Reading Signs Skeptically – The Toxic Talc Myth

There’s an inner city suburb in Sydney called Newtown, which is a fantastic place to spend a few hours, wandering up and down the main street, looking at shops and stopping for a coffee or a snack.

Newtown is around four kilometers south-west of the Sydney CBD. In the 1960s and 70s, affordable share-housing and the suburb’s close proximity to the city and universities drew in a large student population and Newtown became something of a bohemian centre, with a thriving cafe and live entertainment culture. Currently, Enmore Road and King Street host over 600 shopfronts… and some of the retailers who have set up in the area make some rather questionable claims.

Recently, The Skeptic Zone took a walk down King Street, Newtown, and in the window of a natural cosmetics shop, noticed this sign:

toxictalcsign

“TALC is closely related to ASBESTOS.
talc particles have been shown to cause tumors in the ovaries + lungs of cancer victims…
TALCUM is often the No. 1 ingredient in cosmetics. Its cost is ⩷ $50 PER METRIC TONNE! $ $ $ $ DO THE MATHS!!

T.C.K. IS A NANO-FREE ZONE

nano particles are the ticking time bomb of this generation – along with G.M.O
these particles cross the brain/blood barrier.
A BILLION NANO PARTICLES FIT ON THE HEAD OF A PIN!
The Rave of ‘invisible sunscreens is not so glamorous!
WE DON’T USE “Z-COAT ZINC” IN ANY FOUNDATIONS!!! OR PRODUCTS!!!

* KNOWLEDGE; IF NOT APPLIED, BECOMES A BURDEN…

xx”

So that’s a rather scary claim, that talc causes cancer… and I’m very happy reassure you that it is a myth. It’s an interesting one though, as it did originally have some basis in fact.

The shop window sign claims that talc is closely related to asbestos. This sounds rather alarming, given that most Australians are quite familiar with asbestos fibre inhalation related illnesses, including malignant lung cancer, mesothelioma, and asbestosis, and the controversy surrounding and closing down of the asbestos mining and manufacturing industries.

As far as mineral composition goes, talc it fairly closely related to asbestos – talc is hydrated magnesium silicate, asbestos constitutes a set of six naturally occurring silicate minerals. However, this does not suggest that talc is a danger. A parallel claim would be to suggest that water, H2O, is dangerous because it has a similar chemical composition to hydrogen peroxide, H2O2. Unlike water, hydrogen peroxide is an oxidant, corrosive and creates localised capillary embolism on contact with human skin. That one extra oxygen molecule resulting in an unstable peroxide bond makes a heck of a lot of difference.

So where’s the fact?

Because of their similar composition, talc deposits are often found close to asbestos deposits. As such, talc deposits can be contaminated with asbestos. While the talc itself is very much innocuous, talc products produced prior to 1973 were sometimes contaminated with asbestos. In 1973, regulation of talc products was introduced, resulting in prior risks associated with contaminated talcum powder being abolished.

Modern talc refining processes are stringently monitored and there is no risk of lung disease associated with modern talcum powder or talc products.

The ovarian cancer claims are based on studies which found an increased ovarian cancer risk associated with the use of talcum powder, but relied on self-reports over a large time period and as such, were unable to measure either the purity of the talc used by participants, nor the frequency and dose at which it was applied. As such, no causal link has been drawn between talc and ovarian cancer, and studies have been deemed inconclusive.

Now… nanoparticles! There is no known health risk associated with products containing nanoparticles applied to the skin. In 2013, the Therapeutic Goods Administration published a review of relevant studies, which concluded that nanoparticles do not penetrate the skin beyond the outermost layer. Systemic absorption of nanoparticles is unlikely. Zinc oxide nanoparticles in particular have been studied; when exposed in vivo to human immune cells, the immune cells absorbed the nanoparticles and broke them down.

Claims regarding the dangers of nanoparticles in skin products are not based on any credible evidence… nor, for that matter, is the other suggestion slipped in on the sign that GMOs pose a health risk to humans, (despite the public successes of anti-GMO campaigners).

You know… I get the impression that the people who run the natural cosmetics store very likely believe that they are doing good. I could be cynical and come to the conclusion that they’re knowingly using bnon-evidence based fear tactics to sell their products, but that’s something I rarely come across when encountering people who manufacture products based around naturalistic fallacy and false dangers.

I think that it’s far more likely that perhaps at some point the store owners came across misinformation on the dangers of talc and nanoparticles, took it as fact, and built a business around something that they felt was going to be good for people. Likewise, the vast majority of alternative medicine practitioners, crystal sellers and other assorted woo-peddlers strike me as genuinely wanting to and believing that they are doing good.

Does this excuse the fact that their practices are not based on solid scientific evidence? Not at all – I feel that everybody has a responsibility not to spread misinformation and pseudoscience, particularly when such can cause people to forego evidence based medical assistance or advice, be seriously out of pocket buying magic beans, or place faith in myths rather than facts.

However, I still try to remain somewhat charitable in dealing with the people who make these claims… they’re rarely made with malicious intent. Likewise, I hope that people are able to understand that when we question their claims and ask for evidence, we’re not doing so to be malicious, smug or dogmatic.

Anyhow – I think that it’s worth keeping an eye out when you’re passing by shop windows or public notice boards, particularly in areas with higher concentrations of alternative lifestylers, alternative practitioners and the like. It can make for a good opportunity to keep on top of the sorts of claims being made, and prompt some interesting fact-finding and discussion!

This post is an excerpt from Evidence, Please on The Skeptic Zone #335 {Permalink}. Also included in the podcast report, are Richard Saunders and Ian Bryce discussing another sign spotted in Newtown, which made claims regarding “crystal bed” therapy, which was in a new age shop window.

Further reading:
American Cancer Council Fact Sheet on Talcum Powder and Cancer
Cancer Council Western Australia: Cancer myth: Talcum powder and cancer
Cancer Council Australia: Nanoparticles and Sunscreen