1. Oct 03, 2019

Can Dark Chocolate Benefit Visual Function and Retinal Perfusion?

After reports from a previous randomized clinical trial reporting vasodilating flavanols in dark chocolate benefit visual function, a new study assessed the effects of dark chocolate flavanols on subjective visual function and retinal perfusion using optical coherence tomography (OCT) angiography.

The randomized, masked double-blind crossover clinical trial analyzed 22 participants in July 2018. Participants were randomized to one of two groups: dark chocolate or milk chocolate. Participants in the dark chocolate group received 20 g of dark chocolate containing 400 mg of flavanols and participants in the milk chocolate group received 7.5 g of milk chocolate. Visual function and retinal perfusion on OCT angiography were examined after 2 hours.

Results showed that there were no significant changes in retinal perfusion between groups (superficial plexus 48.0% for the dark chocolate group vs 47.5% for the milk chocolate group, treatment effect: −0.59 [95% CI, −2.68 to 1.50], P = .56; deep plexus 54.1% vs 54.0%, treatment effect: −1.14 [95% CI, −4.01 to 1.73], P = .42). No short-term effects of flavanol-rich dark chocolate were reported for retinal blood flow or visual function.

Future trials with larger samples are needed to better assess potential long-term effects.


Siedlecki J, Mohr N, Luft N, Schworm B, Keidel L, Priglinger SG. Effects of flavanol-rich dark chocolate on visual function and retinal perfusion measured with optical coherence tomography angiography: A randomized clinical trial [published online ahead of print September 2019]. JAMA Ophthalmol. doi: 10.1001/jamaophthalmol.2019.3731.