Dark chocolate triggers mood-boosting changes in the gut

Cocoa, used in the production of dark chocolate, is rich in iron, fibers, and phytochemicals – powerful chemical compounds found in plants, which boost immunity and reduce the risk of cardiovascular diseases, cancer, dementia, arthritis, and stroke. Now, researchers have found that a moderate daily intake of dark chocolate can improve the mood too.

A study led by the Seoul National University in South Korea has demonstrated that healthy adults who ate 30 grams of 85 percent dark chocolate per day (about a third of a normal 100 grams bar of chocolate that supermarkets usually sell) were happier compared to those who ate chocolate with less cocoa in it, or no chocolate at all.

“Dark chocolate has long been recognized for its mood-altering properties,” the study authors wrote. “However, the evidence regarding the emotional effects of daily dark chocolate intake is limited. To the best of our knowledge, this is the first study that provides evidence that dark chocolate consumption in everyday life influences physiological and psychological states.”

In order to test this hypothesis, the scientists enrolled 46 participants, and asked them to consume either 30g of 85 percent dark chocolate, or 30g of 70 percent cocoa chocolate, or no chocolate at all each day for three weeks. The participants’ moods were assessed by using the self-report questionnaire “The Positive and Negative Affect Schedule” (PANAS). 

Moreover, in order to assess the possible associations between the mood-altering effects of dark chocolate and gut microbiota, the researchers also analyzed participants’ fecal samples.

The scientists found that consumption of 85 percent dark chocolate significantly reduced negative mood states and increased gut microbial diversity. Participants who ate this type of chocolate had particularly high levels of Blautia, a type of gut bacteria known to be associated with positive mood changes.

According to the researchers, the mood-altering properties of 85 percent dark chocolate are probably “mediated by changes in the diversity and abundance of intestinal bacteria.”

“These findings indicate that dark chocolate exerts prebiotic effects, as evidenced by its ability to restructure the diversity and abundance of intestinal bacteria; thus, it may improve negative emotional states via the gut-brain axis,” they concluded.

The study is published in the Journal of Nutritional Biochemistry.  

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By Andrei Ionescu, Earth.com Staff Writer