In disappointing news for chocolate lovers, researchers have found that contrary to an earlier report, eating dark chocolate will not improve your vision. The earlier report suggested that certain aspects of vision improved within a couple of hours of chocolate consumption. The new study showed no changes in vision or blood flow to the eyes after consuming about three quarters of an ounce of dark chocolate. Both studies, however, involved only a small number of volunteers.
With two similar-sized trials yielding opposite results, "more research is needed," said the authors, led by Dr Jacob Siedlecki of Ludwig-Maximilians-University in Munich. "As this small study does not rule out the possibility of benefits, further trials with larger sample sizes would be needed to rule in or out possible long-term benefits confidently," Siedlecki and his colleagues write in JAMA Ophthalmology.
The reason for suspecting dark chocolate might help with vision is that the sweet treat is bursting with flavonoids, which are antioxidants. Studies have shown that supplements with high levels of antioxidants can reduce the risk of an age-related vision problem called macular degeneration. The specific flavanol in dark chocolate has also been shown to dilate blood vessels, the researchers note.
To see if the earlier study on chocolate and vision could be duplicated, Siedlecki and colleagues rounded up 22 healthy volunteers, ages 20 to 62, who had no vision issues. The volunteers were randomly assigned to consume either a 20-gram (0.71 oz) piece of dark chocolate - equivalent to about a quarter of a dark chocolate candy bar and containing 400 milligrams of flavanols - or 7.5-gram piece of milk chocolate containing roughly 5 mg of flavanols.