Reviewed: Yoon H-S, Kim JR, Park GY, et al. Cocoa flavanol supplementation influences skin conditions of photo-aged women: a 24-week double-blind, randomized, controlled trial. J Nutr. 2016;146(1):46-50.
Cocoa products derived from the dried, fermented fatty seeds of the cacao (Theobroma cacao, Malvaceae) tree reportedly have many health benefits. They are rich in polyphenolic antioxidants and flavanols, such as epicatechin, catechin, and procyanidins. Determining an adequate daily dose and duration of cocoa flavanol supplementation may help maximize potential antioxidant photoprotective benefits. However, previous clinical trials that have investigated the effects of high-flavanol cocoa product consumption on skin photo-aging have had conflicting results. These authors conducted a 24-week, double-blind, randomized clinical trial to investigate whether a high-flavanol cocoa beverage would improve the moderately photo-aged facial skin of female subjects.
The study included healthy females (aged 43-86 years) with visible wrinkles. It was conducted between February 2014 and March 2015 at Seoul National University Hospital in Korea. Sixty-four subjects were randomly assigned to either the cocoa group or the placebo group (n = 32 for both). Of those subjects, one from each group failed to follow the protocol and did not complete the study.
The cocoa group’s beverage contained 4 g fat-reduced cocoa powder (Barry Callebaut Belgium NV; Lebbeke-Wieze, Belgium) that was processed to preserve a high amount (320 mg) of cocoa bean flavanols. The placebo group consumed a nutrient-matched cocoa-flavored beverage that did not contain flavanols. Both beverage powders were dissolved in 150-200 mL hot water.
Wrinkles were measured in the crow’s feet area on the outer corner of the eye using a visiometer (a skin topography tool) to assess the following five variables: skin roughness, maximum roughness, average roughness, smoothness depth, and arithmetic average roughness. Another cosmetological tool was used to measure skin elasticity on the cheek to assess gross elasticity, net elasticity, and biological elasticity. Finally, the authors evaluated skin hydration on each subject’s cheek using two additional tools.
The facial skin of each subject was evaluated at baseline and at 12 and 24 weeks. Ten subjects in each group agreed to undergo short-wave ultraviolet (UV)-B irradiation. The minimal erythema dose (MED), or the minimal UV dose causing erythema (i.e., skin reddening), on all edges of an irradiated square of skin on the buttock was assessed at baseline and at 24 weeks in those subjects.
Adverse effects were evaluated at 12 and 24 weeks. Blood samples were drawn at baseline and at 24 weeks to measure aspartate aminotransferase and alanine transaminase levels (which can be used to gauge tissue damage), as well as glucose, blood urea nitrogen, creatinine, and hemoglobin and hematocrit concentrations. Overall compliance rates were 97.6% at 12 weeks and 98.4% at 24 weeks.
The authors report no significant between-group differences in skin roughness measurements after 12 weeks of supplementation. After 24 weeks, however, the mean percentage changes in average roughness (P = 0.023) and maximum roughness (P = 0.03) were significantly lower in the cocoa group than in the placebo group. “Because visiometer values decrease as wrinkles diminish, these results suggest that the cocoa group showed improvement in wrinkle severity compared with the placebo group,” the authors explained. Changes in the other roughness variables were not significant at 24 weeks.
The only significant between-group difference in skin elasticity after 12 weeks was in the mean percentage change in gross elasticity of the skin, which was significantly greater in the cocoa group than in the placebo group (P = 0.02). After 24 weeks, significant between-group differences were observed in gross elasticity (P = 0.027), net elasticity (P = 0.027), and biological elasticity (P = 0.032), which were all greater for the cocoa group than for the placebo group. No significant between-group differences were seen in epidermal hydration variables after 12 or 24 weeks of supplementation.
No adverse effects were reported, and no abnormal laboratory values were observed. Body weight changes were minimal; the placebo group gained more weight than the cocoa group after 24 weeks (P = 0.021). Although cocoa flavanols have been reported to have beneficial effects on obesity, in this study, the subjects’ diets and physical activities were not controlled, so this finding “can only be interpreted as indirect evidence and was an unintended outcome.” Furthermore, the authors did not report the test product’s content of methylxanthines, which are thought to contribute to weight loss.
The MED of those in the placebo group who underwent UV irradiation did not change significantly during the study. In the cocoa group, however, a significantly increased MED was observed at 24 weeks (P = 0.022). Changes in MED at 24 weeks from baseline were significantly higher in the cocoa group than in the placebo group (P = 0.035).
Although this study found that a high-flavanol cocoa beverage can improve facial wrinkles and skin elasticity, the effects were not as great as those reported for direct curative therapies, such as topical tretinoin (a prescription acne treatment), laser resurfacing, or chemical peeling. “Therefore, the main effect of cocoa flavanols on photo-aging might be preventive rather than curative,” the authors state.
According to the authors, the changes in wrinkle severity and skin elasticity in their study are consistent with those of previous trials.1,2 Conflicting results regarding changes in MED after cocoa flavanol consumption remain, possibly because of the variations in age, skin phototype, and race of subjects used in other trials. The cocoa flavanols did show overall protective effects by raising MED.
The authors conclude that “in moderately photo-aged women, regular cocoa flavanol consumption had positive effects on facial wrinkles and elasticity,” and that “regular cocoa flavanol consumption may be a good strategy for prevention of the progression of skin photo-aging.” No mention was made about what company or agency sponsored the research.
- Heinrich U, Neukam K, Tronnier H, Sies H, Stahl W. Long-term ingestion of high flavanol cocoa provides photoprotection against UV-induced erythema and improves skin condition in women. J Nutr. 2006;136(6):1565-1569.
- Mogollon JA, Boivin C, Lemieux S, Blanchet C, Claveau J, Dodin S. Chocolate flavanols and skin photoprotection: a parallel, double-blind, randomized clinical trial. Nutr J. 2014;13:66. doi: 10.1186/1475-2891-13-66.