German researchers have shown that ingesting types of chocolate rich in cocoa solids and flavonoids—dark chocolate—can fight skin cancer. Their findings come from a trial of just 24 women who were recruited to add cocoa to their breakfasts every day for about 3 months. Half the women drank hot cocoa containing a hefty dose of flavonoids, natural plant-based antioxidants. The remaining volunteers got cocoa that looked and tasted the same but that had relatively little of the flavonoids.
At the beginning and end of the trial, Wilhelm Stahl of Heinrich-Heine University in Düsseldorf and his colleagues conducted a host of tests on each volunteer. One assessment involved irradiating each woman's skin with slightly more ultraviolet (UV) light than had turned her skin red before the trial began. The skin of the women who had received the flavonoid-rich cocoa did not redden nearly as much as did the skin of recruits who had drunk the flavonoid-poor beverage. Women getting the abundant flavonoids also had skin that was smoother and moister than that of the other women. 'Overexposure to UV light can foster the development of skin cancer so a dietary source of skin protection might offer some innate defense for sunny days when an individual doesn't use sunscreen,' Stahl's team said. Chocolate, these scientists note, is just the latest in a range of antioxidant-rich foods holding the potential to shield skin from sun damage.
The researchers recruited women between the ages of 18 and 65. Each volunteer received packets of a dry powder to mix each day with 100 milliliters of hot water—roughly a half cup. Half of the women received powder containing 329 milligrams of flavanols, a type of flavonoid, per serving. The rest got powder delivering a mere 27 mg of flavanols per serving. The primary flavanols were epicatechin and catechin.
Stahl's team reports that the women drinking the high-flavonoid cocoa had 15 percent less skin reddening from UV light after 6 weeks of cocoa consumption and 25 percent less after 12 weeks of the trial. Both figures are comparisons with the same women's response to UV light before the study started. The women drinking the cocoa with low flavonoids showed no change during the trial.
So, could a person realistically add enough flavonoids to his or her diet to produce the benefits suggested by the study? Flavonoid quantities in the richer cocoa were "similar to those found in 100 grams of dark chocolate," Stahl's group reports.
The cocoa drink provided its flavonoids in a serving that delivered only about 50 calories—far below the 400 to 500 calories ordinarily encountered in candy providing a walloping dose of flavanols. Schmitz concludes that people can, in theory, get this efficacious dose without blimping out.