Supplements Provide Nutrition for the Skin
by Heather Granato
Exposure to the sun causes 90 percent of extrinsic aging (photoaging). The formation of collagen in the skin is significantly decreased as a result of exposure to sunshine. Free radicals are generated in the skin as a result of exposure to UV light. They are responsible for at least part of the degenerative changes leading to cutaneous aging. The skin is probably the most susceptible target organ to environmental oxidative stress, because it is most directly exposed to UV radiation and to substances known to generate free radicals in the presence of oxygen. The skin has several lines of defense, including melanin, which acts as a UV-absorbing filter and free-radical scavenger, and antioxidant enzyme systems. Particular antioxidants that have shown to be effective include vitamins A, C and E, the carotenoids, flavonoids and certain minerals such as zinc and selenium.
In an Australian dermatology study, researchers found that increased consumption of fish, beans, lentils, peas, carrots, Swiss chard, pumpkin and cruciferous vegetables (such as broccoli and cauliflower) meant decreased incidence of skin cancer. Also, increased consumption of foods that were high in beta-carotene and vitamin C, such as spinach, papaya and apricots, correlated to a decreased incidence of skin cancer. Skin melanin concentration can be increased significantly through intake of antioxidants such as Pycnogenol, beta-carotene, lycopene, vitamin E and vitamin C.
Pycnogenol, an extract of French maritime pine bark, is one natural and water-soluble supplement shown to have antioxidant and circulatory benefits. A study presented at the Experimental Biology '99 conference in Washington found that the substance may be used to reduce the risks associated with skin disorders induced from ultraviolet radiation. According to the lead researcher, Lester Packer, Ph.D., Pycnogenol is able to decrease or turn off genes that have been damaged by UV rays. "We are gaining a better understanding of how UV radiation causes free radicals and are now discovering the powerful influence antioxidants have in scavenging these radicals before they can damage the skin," Packer says.
Other research backs up the power of various types of antioxidants. While beta-carotene is perhaps the best known antioxidant carotenoid, other types of carotenoids, including lutein, are gaining more attention. Lutein plays an important role in reducing the risk of age-related macular degeneration and decreasing the formation of cataracts; it is now postulated that it also plays a photoprotective role for the skin. "We knew that antioxidants are found in the skin and offer natural sun protection," says Hubert Greenway, M.D., with Scripps Clinic in La Jolla, Calif. "Lutein may also play a role in fighting free-radical damage to the skin."
A study published in the Journal of Dermatological Science last year tested the ability of various carotenoids to protect against UV light-induced damage in vivo. Researchers tested the antioxidant potential of beta-carotene, lutein and astaxanthin to protect cells against UV damage and to repair cells after damage had occurred. Each of the carotenoids showed particular activity against types of damage. "Carotenoids other than beta-carotene may be of importance as biological antioxidants," the researchers wrote.
The research is fairly extensive and still being developed. A 1993 study showed that in an in vitro cellular system, lutein was a more effective antioxidant than beta-carotene. However, beta-carotene has several studies that show its ability to protect against UVB-induced skin tumors. A mixed carotenoid supplement, then, may offer the best internal protection for consumers looking to bolster their skin's antioxidant defenses.
External Factors
While internal protection is important, the skin also is able to take in nutrients transdermally. Offering a host of skincare products that contain antioxidants and other natural ingredients that repair skin damage and reverse signs of aging shows an interest in customers' whole health.
One interesting study found that vitamin A, in the form of Retinoic Acid (Retin-A) may protect skin from sun damage. The study, published in the April 1999 issue of Nature, found that ultraviolet radiation effectively causes a functional vitamin A deficiency in the skin by reducing the expression of certain proteins necessary to maintain levels of vitamin A. In the study, conducted at the University of Michigan in Ann Arbor, 70 volunteers were subjected to various amounts of UV irradiation. Researchers found that after this exposure, there was substantial reduction in two proteins that are essential to maintaining vitamin A levels.
This research counters the advice of some dermatologists, who advise patients using Retin-A to avoid the sun because it increases the likelihood of sunburn. "There's nothing in the literature that suggests this [avoiding the sun] and I have not seen evidence of it," says John Voorhees, Ph.D., co-author of the Nature study. Voorhees added that taking vitamin A internally doesn't seem to have the same effects as topical application. "When Retin-A is applied topically, it saturates the receptors, which is what you need," he says.
Other antioxidants also are gaining respect for their ability to reverse or reduce the signs of age and skin damage. Vitamin C, for example, is one of the most popular products now available in topical form. Ester-C, a trademarked form of vitamin C from Inter-Cal, is one of the most popular forms of this antioxidant because its water processing makes it more bioavailable. Because vitamin C is essential for the formation of collagen, transdermal delivery is an ideal way to ensure the skin gets the antioxidant support it needs. "Many researchers feel that low levels of vitamin C will affect the integrity and the suppleness of the skin," says Dr. Phillips Brown, a researcher with Inter-Cal. "By applying topical vitamin C, you may help strengthen the collagen."
One precaution about using vitamin C, or any antioxidant, topically is that it tends to deteriorate quickly when exposed to light, heat or humidity. In natural products formulations, in particular, which use natural preservatives, it is important to find products that have been stabilized. High-quality skin creams and serums are available not only in department stores, but also from natural products companies such as Kiss My Face, Camocare, Zia Cosmetics, Aubrey Organics and Jason Natural Products.
