The connection between diet and physical beauty has been an area of increasing interest in popular culture as well as in the scientific community. Numerous supplements, plant derivatives, and antioxidants have been proposed to help improve skin conditions and prevent signs of aging.1 Clinical and basic research has played an important role in confirming or debunking these claims, leading to new insight into oral supplements that may play a role in improving signs of photoaging, as well as symptoms of common skin diseases such as acne vulgaris (AV), atopic dermatitis (AD), and psoriasis. This article reviews some of the vitamins, supplements, and antioxidants that have been studied in the improvement of these conditions.
Recently, there has been increased interest among researchers in the role of antioxidants in combatting photoaging. The main determinants of photoaging are chronic sunlight exposure and melanin density. Photoaging presentation includes deep rhytides, pigmentary changes, dryness, loss of skin tone, leathery appearance, and actinic purpura.2-4
Beta-carotene is a fat-soluble derivative of vitamin A, which has retinol activity and has an inhibitory effect on free radicals. It has been used to decrease the effect of UV light on the skin as well as to treat erythropoietic porphyria.5-7 One study evaluated the efficacy of low-dose and high-dose beta-carotene in improving facial rhytides and elasticity in a cohort of 30 women older than 50 years.8 Participants were given 30 or 90 mg of beta-carotene once daily for 90 days, and the final results were compared to baseline. Those who received the 30-mg dose showed improvements in facial rhytides and elasticity, increased type I procollagen messenger RNA levels, decreased UV-induced thymine dimer staining, and decreased 8-hydroxy-2′-deoxyguanosine staining. The lower dose of beta-carotene was found to prevent photoaging and was superior to the higher dose, which actually significantly decreased the minimal erythema dose (indicating a deleterious effect)(P=.025).8
Another study compared the role of a 25-mg carotenoid supplement vs a combination of carotenoid and vitamin E (335 mg [500 IU] RRR-α-tocopherol) supplements in preventing erythema development on the back.9 Using a blue light solar stimulator for illumination, erythema on the dorsal back skin was significantly reduced after week 8 (P<.01). The erythema was lower in the combination group than the carotenoid group alone, but the difference was not statistically significant. Furthermore, after 12 weeks, yellowing of the skin was observed in both groups, especially the skin of the palms and face.9
Collagen peptides also have been used in the prevention and repair of photoaging. Proksch et al10 conducted a double-blind, placebo-controlled trial to investigate the role of collagen peptides on skin elasticity in 69 women aged 35 to 55 years. At 4 weeks, oral supplementation of collagen hydrolysate (2.5 g once daily or 5 g once daily for 8 weeks) showed significant (P<.05) improvement of skin elasticity in both the low-dose and high-dose groups in women older than 50 years; however, collagen peptides did not lead to statistically significant improvement in skin hydration or transepidermal water loss. No known side effects were reported; thus, collagen peptides may be both efficacious and safe in improving signs of photoaging in elderly patients.10 Thus, these studies have shown potentially positive effects of beta-carotene, vitamin E, and collagen peptides in improving the signs of photoaging.