DALLAS — Gut microbes that consume dark chocolate ferment it into anti-inflammatory compounds that are good for the heart, according to research presented at the American Chemical Society’s 247th annual meeting and exposition on March 18.

“We found that there are two kinds of microbes in the gut: the ‘good’ ones and the ‘bad’ ones,” said Maria Moore, an undergraduate student at Louisiana State University and one of the study’s researchers. “The good microbes, such as Bifidobacterium and lactic acid bacteria, feast on chocolate. When you eat dark chocolate, they grow and ferment it, producing compounds that are anti-inflammatory.”

The other bacteria in the gut are associated with inflammation and may cause gas, bloating, diarrhea and constipation. These include some Clostridia and some E. coli.

“When these compounds are absorbed by the body, they lessen the inflammation of cardiovascular tissue, reducing the long-term risk of stroke,” said John Finley, Ph.D., who led the work and is a professor at Louisiana State.

He said that this study is the first to look at the effects of dark chocolate on the various types of bacteria in the stomach.

The team 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, Dr. Finley said.

He said cocoa powder, an ingredient in chocolate, contains several polyphenolic, or antioxidant, compounds such as catechin and epicatechin, and a small amount of dietary fiber. 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,” Dr. Finley said. “These smaller polymers exhibit anti-inflammatory activity.”

Dr. Finley also noted that 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 out competes any undesirable microbes in the gut, like those that cause stomach problems,” he said.

Dr. Finley said people may experience even more health benefits when dark chocolate is combined with solid fruits like pomegranates and acai. Looking to the future, he said that the next step would be for industry to do just that.