Nutraceuticals and Nanoparticles

Posted: August 28, 2007

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Prof. Dr. Jürgen Lademann (Charité University, Berlin, Germany) spoke at the “Trailblazing the Skin Frontier” Workshop, held at George Washington University in Washington, DC, USA, from Aug. 11-13, 2007. He and his colleagues showed that 5-µm diameter nanoparticles penetrate preferentially into the infundibulum, the small gap between the hair shaft and the inwardly curving skin. This means that titanium dioxide or zinc oxide of the same proportions should also, to some extent, penetrate the skin. But is this a reason for not using particulate sunscreens, as consumer watchdog programs want consumers to believe? Does this not remind you of a similar situation a few years ago when we were told not to use organic sun filters because of their estrogenic activity? As Prof. Lademann said, it is much, really much more dangerous not to use a sunscreen than to have these minute amounts of titanium dioxide or zinc oxide penetrating into the body.

Both topics, nutraceuticals and nanoparticles, have a great future ahead of them. In the case of nutraceuticals, long-term clinical studies will have to show their benefit and these studies will not be as easy as those examining topical cosmetics. Testing topical cosmetics tends to involve on one arm, applying the product with the cosmetic; on the other, applying a placebo or no product at all. Every subject acts as his or her own control. These so-called paired comparisons mean that fewer subjects are required to show a statistically significant difference.

But this will not be possible with nutraceuticals. If you eat the active ingredient, then it may or may not end up in the skin. If it does, it goes everywhere and treats the skin everywhere. Clinical trials demonstrating the benefit of nutraceuticals are therefore more complicated than most other cosmetic trials. And whereas any improvement on a site where a product has been applied topically is immediately assumed to be caused by this product--after all, it makes sense, doesn’t it?--colleagues in the nutraceutical arena have all appearances against them, even if the skin appearance is excellent. How do you conclusively show that the observed skin improvement was caused by eating a product? For the moment being, I remain skeptical--not about the technical side, but about the capabilities to convince the consumer.

Nanoparticles, however, are a new subject area that offers great opportunities. They have great potential as a delivery device, a sensory clue, a reservoir for targeted and controlled and event-controlled delivery, to name a few.

In short, this may have been my first column on these issues for the C&T Today e-newsletter, but I am certain that there will plenty more to report in a year’s time on both subjects. Just stay tuned!