Study leader John Finley of Louisiana State University and colleagues tested three cocoa powders using a model digestive tract, comprised of a series of modified test tubes, to simulate normal digestion. They then subjected the non-digestible materials to anaerobic fermentation using human fecal bacteria, Finley explained.
Cocoa powder, an ingredient in chocolate, contains several polyphenolic, or antioxidant, compounds such as catechin and epicatechin, and a small amount of dietary fiber, Finley said.
Both components are poorly digested and absorbed, but when they reach the colon, the desirable microbes take over.
"In our study we found that the fiber is fermented and the large polyphenolic polymers are metabolized to smaller molecules, which are more easily absorbed. These smaller polymers exhibit anti-inflammatory activity," Finley said in a statement.
"When these compounds are absorbed by the body, they lessen the inflammation of cardiovascular tissue, reducing the long-term risk of stroke."
Finley noted combining the fiber in cocoa with prebiotics is likely to improve a person's overall health and help convert polyphenolics in the stomach into anti-inflammatory compounds.
"When you ingest prebiotics, the beneficial gut microbial population increases and outcompetes any undesirable microbes in the gut, like those that cause stomach problems," Finley added.
Prebiotics are carbohydrates found in foods such as raw garlic and cooked whole wheat flour that humans can't digest but good bacteria like to eat. These also come as dietary supplements.
Finley said people could experience even more health benefits when dark chocolate is combined with solid fruit like pomegranates and acai.
The findings were presented at the 247th National Meeting & Exposition of the American Chemical Society in Dallas.