Chocolate flavanols and skin photoprotection: a parallel, double-blind, randomized clinical trial

Nutr J. 2014 Jun 27;13:66. doi: 10.1186/1475-2891-13-66.

Abstract

Background: Solar ultraviolet (UV) radiation has deleterious effects on the skin, including sunburn, photoaging and cancer. Chocolate flavanols are naturally-occurring antioxidant and anti-inflammatory molecules that could play a role in preventing cutaneous UV damage. We investigated the influence of 12-week high-flavanol chocolate (HFC) consumption on skin sensitivity to UV radiation, measured by minimal erythema dose (MED). We also evaluated skin elasticity and hydration.

Methods: In this 2-group, parallel, double-blind, randomized controlled trial, 74 women aged 20-65 years and Fitzpatrick skin phototypes I or II were recruited from the general community in Quebec City, for randomization to either HFC (n = 33) or low-flavanol chocolate (LFC) (n = 41). A blocked randomisation (4), considering date of entry, skin type and age as factors, generated a sequentially-numbered allocation list. Study participants and research assistants were blinded. Totally, 30 g of chocolate were consumed daily for 12 weeks, followed by a 3-week washout period. MED was assessed at baseline and at 6, 9, 12 and 15 weeks. Main outcome was changes in MED at week 12.

Results: 33 participants in the HFC group and 41 in the LFC group were analyzed with 15 weeks of follow-up. Both groups showed similarly-increased MED at 12 weeks (HFC: 0.0252 ± 0.1099 J/cm2 [mean ± standard deviation (SD)]; LFC: 0.0151 ± 0.1118; mean difference (MD): 0.0100 J/cm2; 95% confidence interval (CI): -0.0417 to 0.0618). However, after 3-week washout, the HFC group presented decreased MED (-0.0248 ± 0.1145) whereas no effect was seen in the LFC group (0.0168 ± 0.1698) (MD: -0.0417; 95% CI: -0.1106 to 0.0272). Net temple elasticity increased slightly but significantly by 0.09 ± 0.12 mm in the HFC group at 12 weeks compared to 0.02 ± 0.12 mm in the LFC group (MD: 0.06; 95% CI: 0.01 to 0.12 ). No significant adverse events were reported.

Conclusion: Our study failed to demonstrate a statistically-significant protective effect of HFC vs. LFC consumption on skin sensitivity to UV radiation as measured by MED.

Trial registration: ClinicalTrials.gov identifier: NCT01444625.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antioxidants / pharmacology
  • Cacao
  • Double-Blind Method
  • Elasticity
  • Erythema / prevention & control
  • Female
  • Humans
  • Middle Aged
  • Polyphenols / blood
  • Polyphenols / therapeutic use*
  • Quebec
  • Radiation-Protective Agents / therapeutic use*
  • Skin / drug effects
  • Skin / radiation effects*
  • Skin Physiological Phenomena
  • Sunburn / prevention & control*
  • Ultraviolet Rays

Substances

  • Antioxidants
  • Polyphenols
  • Radiation-Protective Agents

Associated data

  • ClinicalTrials.gov/NCT01444625