Friday, October 4, 2013
Versatile resveratrol: the ultimate skin care ingredient?
Recently I was honored to join Professors David Sinclair of Harvard and Joseph Vercauteren of the University of Montpelleir at an anti-aging symposium at the invitation of Mathilde Thomas of Caudalie in Paris. Caudalie has been using wine extracts (and specifically resveratrol) in their products for more than 15 years, after Vercauteren identified it in wine grape vines. Sinclair has become well known for his work identifying the role of sirtuin (SIRT) genes in anti-aging, and resveratrol as a natural sirtuin activator. While much remains to be proven, it is fair to say that science is finally beginning to have an impact on skin care. With an increasing understanding of what causes aging in skin cells and how botanical antioxidants such as resveratrol work at a molecular level, there is no excuse to use anti-aging skin care products that don’t multitask.
Before delving into the potential benefits of resveratrol in skin care, it may help to review how resveratrol came into the spotlight in the first place. By just about any measure, moderate wine consumption is among the most potent anti-aging lifestyle habits known. And although resveratrol is present in only small amounts in wine, it is the best known source; coupled with an impressive array of anti-aging properties identified in laboratory conditions, resveratrol has been offered as the mediator of wine’s benefits. Sales of resveratrol supplements have soared. (One study noted that 2/3 of people who take supplements include resveratrol.)
Wine drinkers do enjoy healthier skin. For example, a study from Australia (where skin damage from sun exposure is a big deal) found that wine drinkers had a 27% lower risk of developing premalignant lesions known as actinic keratoses (AK’s.) Another study, from Germany, found that wine consumption – but not topical application of wine to the skin – reduced the redness from controlled exposure to UV light; in other words, a sunscreen you can drink.
From here the picture gets a bit more complicated, so bear with me for a moment. Topically applied resveratrol confers protection against damage from UV light in skin, just as it provides a handy explanation for why wine drinkers have healthier hearts and brains, and live longer. But remember that there isn’t enough resveratrol in wine to produce the effects seen under lab conditions without consuming enormous amounts, and supplements of resveratrol have a problem with what is known as “bioavailability.” That means that enough of it has to be absorbed into the circulation and distributed to the target tissue (in our case, skin) before being metabolized. Our digestive systems are pretty efficient at disposing of resveratrol (or at least metabolizing it into other compounds), and there is a high degree of variability between people.
To make matters even more confused, there is the issue of a phenomenon known as hormesis. This refers to paradoxical effects from the same thing in different amounts. Resveratrol has demonstrated hormesis in several cancer types wherein it promotes growth at low levels but inhibits at higher ones; the opposite may occur with Alzheimer’s and osteoporosis. Balancing these opposing effects is a considerable challenge, even if predictable levels of resveratrol in target tissues could be achieved.
The upshot is that if you are looking for the effects of resveratrol in the skin, it may be best to just put it there in the first place. Fortunately, there is good evidence that resveratrol is absorbed into the skin when applied topically. In Part 2 of this post I will detail the ways in which resveratrol functions as the ideal anti-aging skin care ingredient.