The idea that skin health and beauty can be influenced by nutrition is not new. Vitamin C, for example, is essential for the body's production of collagen, which is necessary for maintaining the elasticity of skin and for healing wounds. Vitamin A is critical for maintaining adequate skin hydration. But mounting evidence indicates that some supplements, when taken orally, may have the ability to ameliorate or prevent certain skin conditions—possibly even diseases such as skin cancer. Here's a snapshot of new research on a few supplements with benefits that extend beyond fundamental nutrition.
Nutrients that protect against sun damage
Overexposure to the sun leads to sunburn—an inflammatory reaction caused by the sun's ultraviolet rays—and contributes to premature skin aging, as well as an increased skin-cancer risk. Most strategies for photoprotection (protecting the skin from sun damage) involve the topical application of sunscreens to block UV rays. However, increasing evidence suggests that oral supplementation with certain nutrients can provide additional benefits and may ultimately prove helpful in protecting against skin cancer.
Dietary flavonoids, carotenoids (including beta-carotene and lycopene, an isomer of beta-carotene) and omega-3 polyunsaturated fatty acids have all demonstrated systemic photoprotective effects in clinical studies.1,2 In terms of plant compounds such as flavonoids and carotenoids, photoprotection makes sense, as these compounds are part of the plant kingdom's own UV-radiation defense system and may exert similar effects in human skin.3 Other supplements that have shown systemic photoprotective effects in clinical studies include vitamins C and E and the trace mineral selenium.2,4
In studies, the photoprotective potential of nutrients is measured in terms of their ability to prevent erythema, the reddening and swelling of the skin that indicates sunburn. Proposed mechanisms for the photoprotective effects of supplements include antioxidant and anti-inflammatory actions.5,6,7 High-flavanol cocoa extract. Recently, a clinical study involving 24 women indicated that a cocoa extract with a high flavanol content was significantly more effective than a low-flavanol extract in both decreasing erythema after UV exposure and improving other measures of skin health.4 Each morning for 12 weeks, the women in the study drank cocoa-powder beverages providing either 326 mg/day or 27 mg/day of flavanols. The major flavanols in the cocoa extract were epicatechin and catechin (also found in green tea); the high-flavanol extract provided 61 mg/day of epicatechin and 20 mg/day catechin. (Orally administered green-tea extracts have demonstrated photoprotective effects in animal studies,8,9 but human studies to confirm these benefits have yet to be conducted.)
For the cocoa study, the women underwent photoprotection tests and other assessments of skin condition before, during and after treatment. Results showed that UV-induced erythema was significantly reduced—15 percent after six weeks and 25 percent after 12 weeks—in women taking the high-flavanol extract, compared with their baseline measurements. No change occurred in the low-flavanol group. Those taking the high-flavanol cocoa extract also had a significant decrease in skin roughness and scaling.4 Carotenoids. Evidence to support the photo?protective benefits of carotenoids, especially lycopene and beta-carotene, continues to grow.3,10,11 Carotenoid compounds ingested via the diet are distributed to the skin, where they exert their protective effects.3
According to recent study results, lycopene—the main carotenoid in tomatoes—may be effective in protecting against UV sensitivity.3,12 One study suggested that 12 weeks of supplementation with 10 mg/day of natural lycopene (in the form of a tomato extract and a drink containing tomato extract) provided effective protection against UV-induced erythema; the natural tomato extract and the beverage were both more photoprotective than synthetic lycopene.12
In addition, mixed carotenoids may be as effective as beta-carotene alone when it comes to protecting against UV sensitivity. In a randomized, placebo-controlled clinical trial from 2003, long-term treatment with beta-carotene and a mixed carotenoid supplement (containing equal parts beta-carotene, lycopene and lutein) provided equally effective photoprotection.10 The 36 study participants were divided into three equal groups and randomly assigned to take 24 mg/day beta-carotene, 24 mg/day mixed caro?tenoids or placebo for 12 weeks. Erythema responses to UV radiation were measured at baseline and again after six and 12 weeks of treatment. After 12 weeks, the intensity of erythema responses 24 hours after exposure to UVR was diminished in both the beta-carotene group and the group taking the mixed carotenoids; erythema responses were also significantly lower than baseline measurements.
Eicosapentaenoic acid. EPA, found in high con?centrations in cold-water fish and other marine oils, has demonstrated photoprotective and anti-aging skin benefits in various preliminary studies, and investigators have suggested that long-term supplementation with EPA might even reduce risks of UVR-related skin cancer.6,13
In a double-blind, randomized clinical study published in 2003, 42 healthy volunteers took daily doses of 4 g purified omega-3 polyunsaturated fatty acids (containing 95 percent EPA) or oleic acid (a monounsaturated, omega-9 fatty acid) for three months. In this study, EPA significantly reduced sensitivity to sunburn as well as UVR-induced expression of skin p53, a marker of acute UVR-induced DNA damage; no change was seen in subjects taking OA.13
Some researchers attribute the photoprotective benefits of EPA to effects on inflammatory mediators, such as interleukins (IL-6 and IL-8) in skin cells;14 other research suggests that EPA may neutralize pro-inflammatory UV-generated prostaglandin E-2.7 While more research is needed to clarify EPA's photoprotective mechanism(s), anti-inflammatory effects seem a more likely explanation than antioxidant actions.
Supplements that improve acne
Acne and psoriasis are chronic skin disorders that are notoriously difficult to treat successfully. Past research suggests that zinc supplements may be helpful for treating acne vulgaris (common acne),15 and a new study suggests that zinc's positive effects may extend to acne rosacea (a particularly stubborn form of acne, common in middle age, that is associated with significant swelling and redness of the facial skin and may also extend to the neck and chest).16,17 Oral tetracycline antibiotics, such as tetracycline, doxycycline and minocycline, are commonly prescribed as part of conventional treatment for either acne vulgaris or rosacea.
Zinc. In a 2001, multicenter, randomized, double-blind clinical trial involving 332 people with inflammatory acne vulgaris, 90 days of treatment with 30 mg/day zinc gluconate (elemental zinc) compared favorably with 100 mg/day of the antibiotic minocycline hydrochloride in decreasing acne papules and pustules.15 Specifically, the researchers reported a 31.2 percent clinical success rate for zinc compared with a 63.4 percent for minocycline after 90 days, with clinical success defined as more than 66 percent decrease in inflammatory lesions on the face. While the antibiotic was clearly superior in improving symptoms, the study nonetheless adds further support for the use of zinc in the treatment of acne.
Another 2006 study assessed the effectiveness and safety of oral zinc sulfate in 19 people with acne rosacea.16 For this double-blind, placebo-controlled study, participants were randomly divided into two equal groups and assigned treatment with either 100 mg/day zinc sulfate or placebo. The researchers reported that mean disease severity scores dropped significantly after one month of treatment in those taking zinc, but larger studies are needed to confirm their results. Three people taking zinc reported mild stomach upset.
Zinc and vitamin B combination. According to the eight-week Nicomide Improvement in Clinical Outcomes Study, combined use of zinc, nicotinamide (a form of vitamin B3) and several other ingredients may also help with acne.17 NICOS was an open-label, multicenter, prospective-cohort study designed to assess the clinical effects of oral Nicomide—a combination of zinc oxide (25 mg), nicotinamide (750 mg), copper (1.5 mg) and folic acid (500 ?g)—in acne vulgaris as well as acne rosacea. Patients were permitted to continue taking any previously prescribed antibiotics during the course of the study. After four weeks of treatment, 79 percent of study participants reported that their appearance was moderately better or much better, and 55 percent reported a 26 percent to 50 percent reduction in lesions. Among the 26 percent of patients who took antibiotics in combination with Nicomide, results were not significantly different than for those who took Nicomide alone. Although more research is needed, the supplement appears to have potential as an adjunct or standalone treatment for both acne vulgaris and rosacea.
Supplements that improve psoriasis
Omega-3, PUFA-rich fish oil is one supplement that historically has shown benefits in psoriasis, a skin disorder with both autoimmune and inflammatory com?ponents.2 New research findings suggest that a milk-derived extract containing bovine growth factors may help reduce the severity of psoriasis symptoms. Bovine growth factors. An experi?mental extract rich in bovine growth factors showed promise in improving symptoms of psoriasis in two preliminary clinical studies.
The first study, which involved only 11 participants, was an open-label study designed to investigate the safety and efficacy of the milk-derived extract XP-828L in mild to moderate psoriasis. After 56 days of treatment, seven of the 11 study participants had reductions in Psoriasis Area and Severity Index scores, a standard assessment tool for psoriasis symptoms. Improvement ranged from 9.5 percent to 81.3 percent.18
The second psoriasis trial, a 2006 randomized, double-blind, placebo-controlled, crossover clinical study, tested XP-828L in 84 people with mild to moderate psoriasis. The study participants were randomly divided into two equal groups and assigned treatment with either 5 g/day XP-828L (given in doses of 2.5 g twice a day) or placebo for 56 days; after this initial treatment period, the two groups were switched. At the end of each 56-day treatment period, there was a statistically significant decrease in physicians' global assessment scores of psoriasis severity, deemed a "trend toward improvement" in psoriasis symptoms; the improvement did not reach statistical significance.19 No adverse effects were reported in either study.
Nutrition has wide-ranging impacts on skin health. New research is likely to bring not only more effective natural treatments for common skin diseases, but also more research-supported strategies for preventing skin aging and disease. Combined topical and oral administration of skin-protective nutrients may yield better results than oral or topical treatments alone. Future strategies for sun protection, for example, may well include combinations of sunscreen and orally ingested supplements for optimal protection against UV radiation.
Evelyn Leigh is a freelance writer and natural-health advocate based in Boulder, Colo.
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