Recent research that questioned the potential of antioxidants to fight against aging has elicited a number of reactions from the industry, questioning the relevance of the findings to human skin.
Earlier this month researchers, led by Dr. David Gems at the University of London published work that questioned the role of oxidative damage in the aging of C. elegans (nematode worm) by knocking out the genes for superoxide dismutase, an important antioxidant enzyme. Although the research only focused on this one organism, the scientists concluded that when the study’s results are taken in conjunction with similar research, the universal acceptance of the oxidative theory of aging is undermined.
The theory that aging is caused by an accumulation of molecular damage resulting from oxidative damage has, according to Dr. Gems, filled a knowledge gap for more than fifty years. But in his opinion it doesn’t stand up to the evidence. “But there is no clear evidence that dietary antioxidants can slow or prevent aging. There is even less evidence to support the claims of most anti-aging products,” he said.
Science backs up topical antioxidants
Industry insiders and dermatologists, however, have taken issue with these conclusions highlighting a body of evidence that supports the use of both dietary and topically applied antioxidants.
An industry insider, who requested to remain nameless, referred to this body of evidence as the ‘elephant in the room.’ “A large body of quality peer-reviewed studies show vitamin C and other antioxidants reduce the appearance of fine lines and wrinkles by protecting cells from free radical damage and by stimulating the production of collagen,” he said.
These thoughts are echoed by dermatologists Dr. Debbie Palmer and Dr. Jennifer Kitchin who state: “It has been demonstrated that topical antioxidant application can provide protection from sun-induced damage, retard skin aging and improve skin appearance.”
Palmer and Kitchin explain that free radicals can promote the oxidation of nucleic acids, proteins and lipids and can damage intracellular structures, including DNA. “In addition, free radicals cause an increase in the production of transcription factors such as activator protein 1, which produces metalloproteinases that can break down collagen, causing wrinkling of the skin,” they added. They also noted the body of evidence that supports the ability of antioxidants to prevent the immunosuppressant action of UV light that can promote skin cancer formation.
SOD not the only line of defense
Furthermore, Kitchin and Palmer note that superoxide dismutase (the gene knocked out in the C. elegans research) is not the only defense an organism can employ against reactive oxygen species.
“We know that superoxide dismutase is only one of the four enzymatic antioxidants that exist. The other three—glutathione, glucose 6 phosphate dehydrogenase and catalase)—in addition to the five non-enzymatic antioxidants, were all left to combat the oxidative stress that the nematodes may have been exposed to.”
Therefore, for the two dermatologists, as for much of the industry, topical antioxidant application remains an exciting and promising area of anti-aging study and treatment.
CosmeticsDesign.com, December 18, 2008