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How to write a good scare storyEarlier this week, a group of researchers found aluminium in breast tissue and, without further evidence, speculated that deodorants, which contain traces of aluminium, cause breast cancer.

Henry’s nicely debunked this story in an earlier post but we’re not quite finished with aluminium scare stories yet.

The same researchers were responsible for another press release earlier this month, where they also speculated on the cancer-causing potential of aluminium, this time in sunscreens. If you want to build a successful scare story, this is a good piece to learn from.

Step One: Find a chemical in an everyday product
In this story, the researchers tested for, and found aluminium salts in seven different sunscreens. Of course, in three of these brands, aluminium was actually listed as an ingredient, so the tests would have been a bit pointless.

Step Two: Don’t subject the results to scientific scrutiny
These tests are the only results reported in the press release and even then, there are no actual figures. All we know is that they found aluminium. There’s no paper that accompanies the results and certainly no ‘peer review’ by other scientists.

Step Three: Invoke the spectre of evil corporations
The press release says that ‘following numerous enquiries, the manufacturers were not forthcoming as to the role of aluminium in their product’.

The wording certainly paints sunscreen manufacturers as sinister operatives, working behind closed doors and being shady about their products.

Except, one company did get back to them, with a perfectly reasonable explanation. They said that the salts help to prevent other ingredients in the sunscreens, the ones that help to block out UV rays, from clumping together.

Step Four: Play with numbers
Based on their measurements, the researchers worked out that on an ‘average day on the beach’ a person would end up applying 1g of aluminium to their skin. That’s if they followed the WHO’s guidelines for sunscreen use which recommend regular re-application.

Which tells us absolutely nothing. Is one gram bad? Since they don’t tell us what levels of aluminium application would be dangerous (probably because there isn’t a definite answer yet), the number’s irrelevant. It also ignores the fact that the WHO recommends people to reapply sunscreen regularly because it (and the chemicals within it) rub off.

The bottom line is that while aluminium can be an irritant, and even a neurotoxin, it’s very unlikely to cause cancer. The vast majority of both human and animal studies have found no evidence of link between aluminium and cancer.

And 1g of something that doesn’t cause cancer is not going to be worse for you than 0.01g of something that doesn’t cause cancer.

Step Five: Invoke the image of chemicals travelling around the body
The press release continues by noting that the skin ‘is permeable to aluminium salts when, for example, they are applied as antiperspirant formulations’. There are those deodorants again…

It continues, “It will accumulate in the skin and be transported to sites throughout the body.” The implication is that the chemicals found in everyday products, used by you, are soaking into your body and travelling around it.

But again, if they are essentially safe, that’s not really a problem. Every time I eat or drink, chemicals are circulating around my body, and thankfully so too.

Step Six: Twist the results of other research
Here’s the bit where the speculations get out of hand. The press release suggests that aluminium in sunscreens could be causing damage in the skin that could ultimately lead to skin cancer.

It points to an earlier Californian study, which showed that some sunscreen chemicals in sunscreens produce ‘reactive oxygen species’ in the skin. These could damage DNA, which could increase the risk of skin cancer. Aluminium could worsen the effects of these oxygen molecules.

That’s a lot of speculative jumps to make from a simple measurement of aluminium levels in sunscreen. Especially since it leaves out some key facts – the Californian team clearly said that sunscreens only produce ROS if they aren’t used properly. They even said “for now, the best advice is to use sunscreens and re-apply them often.”

The press release also noted that sunscreen use has gone up recently, but skin cancers aren’t getting any rarer. As it says, “it has not hitherto been considered that aluminium in these products could be an extremely significant contributing factor.”

Well, there’s a very simple reason for that – there’s no evidence for the idea! Instead, studies have clearly shown that the reason why sunscreens haven’t lowered the incidence of skin cancer is because people use them as an excuse to stay out in the sun and ignore other sun protection methods.

Step Seven: If you acknowledge other possibilities, only do it at the end
And after all that, the press releases’ last paragraph seems to derail its own train of (speculative) thought.

It says, “Aluminium is already in the skin surface and may not need to be a component of sunscreens to exacerbate oxidative damage attributed to the application of such products.”

So basically this chemical that’s meant to be causing us harm is already in our skin.

Comments

Sabine September 3, 2007

Great article. Thanks for the very useful information.

Ed September 3, 2007

Thanks for the comment Sabine – glad to know you found the article useful. I think the problem is that it takes a lot of time to pull together a critical analysis of a piece of research and it would simply be impractical to do this every morning.

Press Gang acts as a round-up of news rather than a commentary on it. We will continue to try and present our take on new research either on this blog or in the News section of News and Resources, but this won’t be feasible for everything.