Natural Cocktail Effect?

red apple with leafI have often seen concern expressed over the sheer number of (synthetic) chemicals used in cosmetics, and over the number of chemicals detected in human breast milk, urine etc. These numbers are then often used to concoct a scare over the potential for a “cocktail effect”, i.e. a mythical series of interactions between these substances that then produces unexpected adverse health effects. I use the term “mythical” because there is no actual proof that such an effect exists; certainly not in the manner suggested. Sense About Science – page 9.

It is notable that this claim is only ever made with respect to synthetic substances. However, let’s consider natural substances instead. To use a very simple example, an apple is natural, and contains hundreds of different substances. Aloe vera is natural and, similarly, contains hundreds of different substances. But how natural is it to put extracts of these plants together on human skin? The hundreds/thousands of different substances contained within extracts of those two plants would never be found in such intimate proximity in nature, so placing them on the skin is no longer reflecting a natural state of affairs. This is just an example, but it may be extrapolated to any almost combination of plant extracts – they would simply never be found mixed together in nature. This opens up the possibility of chemical interactions that are never likely to occur within the plant in its native state. None of these interactions are ever studied (an accusation frequently thrown at synthetic substances), so how do we know that such combinations are safe for use in cosmetics? The safety of the vast majority of the components of natural extracts is not fully established (but frequently assumed – see the Skin Deep database for ample evidence of such assumptions), so how do we know that we are not at risk when using combinations of natural substances in unnatural combinations?

Both benzoic acid and ascorbic acid (vitamin C) exist in nature but, when used in combination, benzene can be produced (this actually happened in Coca Cola – with sodium benzoate, which was replaced very quickly!)

I appreciate that I have stated that the “cocktail effect” does not really exist, so my argument over such an effect with natural materials is very weak, but my point here is that those who DO claim such an effect for synthetics should, logically, accept that the possibility exists for the same effect with natural substances. So, either accept that it doesn’t exist to any significant extent for synthetic substances, or exercise more caution and call for more testing of natural substances – you can’t have it both ways!


  • Lise M Andersen

    Well put Dene. You’ve written yet another blog post I will most likely be referring to. :)

    • Dene Godfrey

      Thanks Lise :-)

  • Dene Godfrey

    I’ve received a private message suggesting that my claims over benzene in Coca Cola are not true – I should have published links and made it clear that other soft drinks brands were also affected (and I will also correct my statement that the situation was resolved quickly – it wasn’t – it took around 10 years!)

    • Katherine

      Every time I turn around with this soft drink stuff, something else pops up that is negative about them as a whole. Boy I sure am glad I just drink water, with my occasional glass of vino at dinner…..ahhh good stuff!

  • Ola

    It’s totally unrelated but I need to ask you something – Dene, would you mind translating your articles about parabens into polish and posting them on my personal blog? Of course I would write that you’re the author and put link to the original article. I must admit that I love that series and it annoys me every time when I read opinions stating that ‘it’s a great product but I won’t buy it anymore because of parabens’…

    • Dene Godfrey

      Hi Ola – I can try to do this using Google translator, but I don’t know how accurate the results would be! Perhaps you would be able to make sure they were correct? Can you contact me directly (a private message via my LinkedIn page would be easiest, I think) so we can take this further? Thanks for your support! :-)