Can dark chocolate improve eyesight?

Health benefits of dark chocolate

In another study of over 2,000 participants, the more chocolate they reported eating (up to twice per week), the less coronary artery plaque they had. And the studies go on and on… We have a pretty good idea that chocolate is good for your cardiovascular health.

This most recent study looked at the effect of milk vs. dark chocolate on three types of visual perception: visual acuity, large and small letter contrast sensitivity. The researchers found that there were improvements in all measures two hours after ingestion of a 47-gram dark chocolate bar (72% cacao).

What helps your heart may also help your vision

There may be a common pathway between the visual perception improvements and the cardiovascular protective effect, namely the effect of plant molecules called polyphenols. The polyphenols found in cocoa are called flavanols. These have an especially positive effect on our blood vessels, by healing damage to the lining, relaxing the muscle, and improving blood flow. Studies have shown that cocoa flavanols also improve blood sugar metabolism and reduce the risk of developing diabetes, as well as reduce risk for heart and vascular disease in patients who have diabetes. The authors of the visual study hypothesize that cocoa flavanols enhance availability of oxygen and nutrients to the blood vessels of the eye and brain. The retina in particular, they point out, is very highly vascularized and may be the area of interest in these study findings.

Should you make dark chocolate part of your health routine?

Given decades of research consistently showing a positive health effect of dark chocolate, we can feel good about recommending regular consumption. But note: the best and most consistent results are from dark chocolate, which can contain between 50% and 90% cocoa flavanols. Milk chocolate can contain as little as 10% up to maybe 50%, and tends to be made with more fat.

Nibble on two squares of dark chocolate (the darker the better) daily to enjoy all of these benefits. Nibble it slowly; it’s very filling. 

Monique Tello, MD, MPH
Contributing Editor

Selected references

Harvard T.H. Chan School of Public Health Nutrition Source: Dark Chocolate

Cardiovascular benefits of dark chocolate? Current Treatment Options in Cardiovascular Medicine, December 2015.

Effects of milk vs dark chocolate consumption on visual acuity and contrast sensitivity within 2 hours: A randomized clinical trial. JAMA Ophthalmology, April 2018.

Use of dark chocolate for diabetic patients: a review of the literature and current evidence.Journal of Community Hospital Internal Medicine Perspectives, September 2017.