A Review of Clinical Trials Conducted With Oral, Multicomponent Dietary Supplements for Improving Photoaged Skin
December 2015 | Volume 14 | Issue 12 | Original Article | 1453 | Copyright © December 2015
Jay Birnbaum PhD,a Anne Le Moigne,b Lisa Dispensa MS RD,c and Larry Buchner BAd
aDermatology Consultant, Montville, NJ
bPfizer Consumer Healthcare, Clinical Excellence and Biometrics, Madison, NJ
cPfizer Consumer Healthcare, Global Nutrition Science, R&D, Madison, NJ
dCanfield Scientific, Business Development, Fairfield, NJ
Although the FDA does not require documentation of efficacy of dietary supplements, prospective clinical studies, including randomized controlled trials, have been conducted with individual micronutrients alone and in combination with other ingredients for promoting skin health. Proposed mechanisms include antioxidation, anti-inflammation, photoprotection, collagen formation, reductions in matrix metalloproteinases, and other effects on photoaging. Literature searches were conducted to identify clinical trials assessing multicomponent dietary supplement formulations on photoaging outcomes. Sixteen studies of various nutrient and non-nutrient ingredients, including essential micronutrients (vitamins, minerals), plant extracts (polyphenols, carotenoids), and marine- or animal-derived ingredients, were identified. Studies were single center, 2–12 months in duration, primarily enrolled women, and evaluated numerous outcomes, including investigator/subject assessments and instrumental/objective measures. Methods to control for potential confounders were implemented in some studies, including limiting sun exposure, cosmetic procedures, and changes in dietary habits/body weight. Given the range of different products, clinical/methodologic heterogeneity, insufficient detail in reporting, and lack of comparable outcome measures, quantitative analysis of results was not possible. Results of individual studies revealed significant improvements from baseline for the dietary supplement group(s) on ≥1 endpoint across all studies; significant differences from placebo were observed in 7 of 12 controlled studies (although only 1 study designated a prospectively defined primary endpoint). Most products had only been tested in 1 study; confirmatory studies were rarely conducted per the publicly available literature. Meaningful assessment of dietary supplements, which typically contain nutrients found in the diet, requires unique methodologic considerations and endpoints appropriate for measuring changes that are more subtle and gradual than those observed with topical/injectable products. Although definitive conclusions could not be drawn from the existing evidence, available data are supportive of beneficial effects of oral multicomponent supplements on skin health. Confirmation of positive effects with the same formulation/endpoint from more than a single study/investigator is needed. J Drugs Dermatol.
While dermatologists recognize that nutritional status and dietary
intake affect various dermatologic conditions and overall skin health,1,2 they are less likely than other specialists, including cardiologists and orthopedists, to recommend dietary supplements.
3 With regard to chronoaging and photoaging, they may "think globally" but "act locally" by focusing predominantly or exclusively on injectable or topical products, including retinoids
and sunscreens,4,5 in part because of a lack of adequate nutrition education/training from medical school curricula6,7 and the perceived dearth of compelling scientific support for dietary supplements.2
To improve the dialogue between clinicians and patients on the role of dietary supplements for skin aging/health, this review summarizes studies evaluating the effects of dietary supplement
formulations on photoaging outcomes. Because the potential benefits of dietary supplements in otherwise healthy individuals may be more subtle than many locally acting products and are apparent only after extended periods, methodologic
considerations are discussed.
Dietary Supplements and Aging Skin
The contribution of both intrinsic and extrinsic (environmental) factors to skin aging is well documented. Exposure to ultraviolet (UV) radiation is the principal cause of skin photoaging.8,9 Reactive
oxidative species and proinflammatory mediators contribute to intrinsic and extrinsic skin aging,4,10 producing various dermal and epidermal alterations.4,8,9 Reports on the effects of individual or combinations of nutrients on these factors are emerging in the literature. In vitro studies, for example, using skin cells or