New study unveils roles of vitamins in skin care

SCHAUMBURG, Ill. A study supporting use of certain vitamins (vitamins A, C, E and B3) in either oral or topical formulations to improve the health of skin was published online Monday in the Journal of American Academy of Dermatology.

“It is well documented that ultraviolet radiation contributes to premature skin aging through the process of photoaging, and there is increasing evidence that the antioxidant properties of vitamins may contribute to the prevention and treatment of photoaging,” stated Jenny Kim, associate professor in the division of dermatology, department of medicine, at the University of California, Los Angeles, and lead author of the study. “In fact, numerous companies developing cosmeceuticals base their effectiveness claims on the fact that their formulations contain vitamins proven in laboratories to modify cellular processes thought to contribute to the appearance of photoaged skin. As dermatologists, we can help our patients navigate this maze of marketing claims by sharing scientific data on the known efficacy of vitamins in skin care products.”

Based on a comprehensive review of the available published data on the role of vitamins in skin care products, Kim and her colleagues found there is evidence to support the potential role of vitamins A, C, E and B3 in modifying the photoaging process. “While it’s evident that these vitamins can play a role in fighting sun damage, the question still remains whether these properties are effective when delivered in skin care products,” Kim said.

The two most common forms of vitamin A studied for their role in protecting the skin from UV-induced damage are retinols and carotenoids. Retinol is found in such foods as liver, milk and eggs, and is the most biologically active form of the vitamin. Carotenoids are found in many fruits and vegetables, and have strong antioxidant capabilities.

While carotenoids are not shown to be beneficial in the treatment of photoaging, research suggested that they may play a role in photoprotection by preventing UV-induced collagen breakdown.

“Although the evidence available at this time is not strong enough to offer definitive support for the use of dietary carotenoids for photoprotection, a role for carotenoids as a supplement to photoprotective agents should not be discounted yet,” Kim said. “We hope to see larger-scale clinical trials conducted to further explore the photoprotective effects of carotenoids.”

Unlike carotenoids, there is vast evidence supporting the role of topical retinoids (the class of substances formed by retinol and its natural and synthetic derivatives) in treating photoaged skin, Kim noted. Prescription retinoid formulations have the most scientific data to support their use in this area.

Kim noted that both tretinoin cream (0.025% and 0.05%) and tazarotene cream (0.1%) are already FDA-approved for the treatment of fine wrinkles, skin roughness and mottled hyperpigmentation caused by aging and sun exposure. In addition, she added that studies of other retinoids have shown that a once-daily application of 0.1% isotretinoin cream for 36 weeks was effective in reducing fine wrinkles.

Retinoids also are found in over-the-counter cosmeceuticals, but there is less clinical evidence supporting their effectiveness in improving photoaged skin. “An important point to remember with retinoids is that we cannot assume that all retinoids are equal in their ability to fight photoaging,” Kim said. “In over-the-counter products, retinol appears to be the most effective retinoid based on clinical studies completed to date.”

Vitamin C, a water-soluble vitamin also known as ascorbic acid that is found in citrus fruits and dark green leafy vegetables, plays an essential role in the production of collagen and elastin. Because of its antioxidant properties, vitamin C may reverse the negative effects of UV radiation in the skin, but there are few clinically controlled studies to confirm this theory.

“An animal study examining the role of vitamin C in reversing sun damage found that when 5% ascorbate was applied two hours before UVB and UVA exposure, UVB-induced skin wrinkling was reduced,” Kim said. “Some of the human clinical trials have shown similar favorable results when applying a daily dose of L-ascorbic acid treatment, but all of these studies involved small sample sizes.”

In addition, Kim pointed out that one concern of adding vitamin C to cosmeceuticals is that vitamin C is unstable when used in formulations, and it is not known how much, if any, intact molecule remains when applied to the skin. “This problem has been partially overcome by chemically modifying ascorbic acid,” Kim said. “However, for the body to use the supplied ascorbic acid, it must convert it to L-ascorbic acid, and many of the stabilized, commercially available forms have not been examined to determine whether this conversion is possible. For that reason, the average consumer will not be able to determine if a cosmeceutical containing vitamin C will be effective.”

Vitamin E, or tocopherol, is a fat-soluble vitamin, and its synthetic form is found in many OTC products. Working as an antioxidant, vitamin E protects cell membranes and is thought to play an important role in skin aging because of its antioxidant properties. While topical vitamin E is available in a variety of products, there is no data which support claims that it improves skin wrinkling, discoloration and texture, Kim said.

“Topical vitamin E has been studied in humans, as in mice, more as a protectant to be used before sun exposure than as an agent to be included in cosmeceuticals to reduce the signs of skin aging,” Kim added. “Through research we have learned that UV exposure significantly decreases levels of cutaneous vitamin E, and vitamin C should be included in any formulation containing vitamin E because of the important role it plays in maintaining active vitamin E levels.”

The B vitamins consist of eight different water-soluble vitamins that are found in a variety of foods. Vitamin B3 has been shown to reduce blood cholesterol and atherosclerosis (a condition in which fatty materials collect along artery walls), but now new insights are examining its role as an effective treatment for several skin conditions — from acne to photoaging.

Specifically, Kim noted that vitamin B3 has been found to increase collagen production in vitro studies and to reduce skin hyperpigmentation (dark spots) in clinical studies. “There has been one clinical trial conducted in Caucasian women in which 50 women applied 5% niacinamide (topical vitamin B3) to one side of their faces twice per day for 12 weeks, and these women experienced significant reductions in the appearance of hyperpigmented spots, redness, wrinkles and yellowing, as well as improved skin elasticity,” Kim said. “While initial studies show promise that topical vitamin B3 may prevent UV-induced skin aging, larger clinical trials are needed to confirm its role as a definitive treatment of photoaging.”