Mystery about health benefits of dark chocolate solved
The health benefits of eating dark chocolate have been extolled for a long time, but the exact reason has remained a mystery — until now. Certain bacteria in the stomach eat the chocolate and ferment it into anti-inflammatory compounds that are good for the heart, according to researchers from Louisiana State University.
The research, which was presented at a meeting of the American Chemical Society on 18 March 2014, showed that the ‘good’ microbes in the gut feed on dark chocolate. The ‘bad’ bacteria in the gut are associated with inflammation and can cause gas, bloating, diarrhea and constipation. These bacteria include some Clostridia and some E.Coli bacteria.
“The good microbes, such as Bifidobacterium and lactic acid bacteria, feast on chocolate,” said Maria Moore, and undergraduate student and one of the study’s researchers. “When you eat dark chocolate, they grow it and ferment it, producing compounds that are anti-inflammatory,” she said.
“When the compounds are absorbed by the body, they lessen the inflammation of cardiovascular tissue, reducing the long-term risk of stroke,” said John Finley, PhD, and leader of the study.
Dr Finley said this study is the first to look at the effects of dark chocolate on the various types of bacteria in the stomach.
The research team tested three cocoa powders using a model digestive tract, comprised of a series of modified test tubes, to stimulate normal digestion. They then subjected the non-digestible materials to anaerobic fermentation using human fecal bacteria.
The researchers said that cocoa powder, an ingredient in chocolate, contains several polyphenolic, or antioxidant, compounds such as catechin and epicatechin, and a small amount of dietary fibre. 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 fibre is fermented and the large polyphenolic polymers are metabolised to smaller molecules, which are more easily absorbed,” Dr Finley said. “These smaller polymers exhibit anti-inflammatory activity,” he said
Dr Finley also said that combining the fibre in cocoa with prebiotics was “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,” Dr Finley said.
Prebiotics are carbohydrates found in foods like raw garlic and cooked whole wheat flour that humans cannot digest but that good bacteria in the gut like to eat.
The researchers said that people could experience even more health benefits when dark chocolate is combined with solid fruits like pomegranates and acai. Dr Finley suggested that this could be a future step for the food manufacturing industry.
The study was supported by the Louisiana State College of Agriculture and Louisiana AgCentre Undergraduate Research Grant.