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Eating Chocolate Every Day is Good for You

By Karyn Maier

New research suggests that eating a piece of dark chocolate each day is -- oh, rapture! -- good for us. But before you rush out to the nearest confectionery, you should know that not all chocolate is equal.

Scientists at the Seoul National University in Seoul, Republic of Korea set out to understand how chocolate affects mood and may even help to thwart disease. The team observed 48 healthy men and women between 20 and 30 years of age who, for three weeks, either consumed 30 grams per day (or just over an ounce) of 85% cocoa chocolate, 70% cocoa chocolate, or, alas for 14 random unlucky study subjects, no chocolate at all. Specifically, the researchers were looking for changes in mood and in "gut microbial diversity," meaning the range of "friendly" microbes in the intestinal tract that are desirable for optimal digestion and overall good health.

The study participants who consumed 85% cocoa chocolate experienced improved mood and greater prebiotic benefits. The researchers surmise that the polyphenol content in chocolate has the ability to "restructure the diversity and abundance of intestinal bacteria; thus, it may improve negative emotional states via the gut-brain axis.” Of particular interest was the increase seen in the 85% cocoa chocolate group in the levels of a species of anaerobic bacteria known as Blautia obeum that contributes to antibacterial activity in the gut and plays a role in deterring the development of inflammatory and metabolic diseases.

However, while the happy study subjects who enjoyed 85% cocoa chocolate each day for nearly a month demonstrated improvement in mood state and in prebiotic activity, the group who consumed 70% cocoa chocolate did not fare as well. Using the Korean version of the Positive and Negative Affect Schedule (PANAS) as a measurement tool, the former group evidenced a significant reduction in negative mood states while the latter group did not. The same results were seen in terms of microbial diversity.

Why does any of this matter? Haven't we heard that chocolate has certain health benefits before? Perhaps, but, according to the researchers, this is the first study to demonstrate the impact dark chocolate has on our physiological and psychological well-being. They further underscored the significance of this finding:

"Mood disorders are a leading cause of disability worldwide. Disturbances in a person's mood interrupts their personal well-being and the ability to participate in social interactions, leading to physical health problems such as chronic diseases. The symptoms of mood disorders include ongoing feelings of sadness, helplessness, hopelessness, and irritability. These disorders are mainly treated with drugs that manipulate the monoaminergic neurotransmitter system in the brain. However, the efficacy of such drugs is in doubt because the drugs are associated with a delayed onset of action and a low response rate. Therefore, the need for a new paradigm to prevent and treat mood disorders has been raised, and relevant research has been conducted in fields including nutrition and microbiome science, with special attention to the relationship between diet and mood."

"The role of diet as a mood regulator has received a great deal of interest," the researchers added. "Certain dietary components have been shown to reduce anxiety and depression and improve quality of life. In particular, cocoa products such as dark chocolate contain a number of nutritional compounds that have the potential to affect mood."


Ji-Hee Shin, Chong-Su Kim, Lina Cha, et al. "Consumption of 85% cocoa dark chocolate improves mood in association with gut microbial changes in healthy adults: a randomized controlled trial." Journal of Nutritional Biochemistry, Volume 99, January 2022, 108854


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