Researchers from the Nestlé Research Center in Switzerland have published evidence that suggests that eating dark chocolate can correct stress-related biochemical imbalances and actually reduce the levels of stress hormones found in the body.

Anecdotal evidence has suggested that the antioxidants found in dark chocolate may reduce risk factors for heart disease, and also ease emotional stress. But until now, there was little evidence from research in humans that could confirm the process.

The research team, led by Sunil Kochhar, administered 40g of dark chocolate to 30 human subjects classified into either low or high anxiety groups based upon validated psychological questionnaires. Urine and blood plasma samples were collected from the participants during three test days at start, midpoint, and end of the two week study. NMR and Mass Spectrometer-based techniques were utilized to observe the changes in metabolism due to the chocolate consumption.

The test subjects in the higher anxiety group "showed a distinct metabolic profile indicative of a different energy homeostasis (lactate, citrate, succinate, trans-aconitate, urea, proline), hormonal metabolism (adrenaline, DOPA, 3-methoxy-tyrosine) and gut microbial activity (methylamines, p-cresol sulfate, hippurate). Dark chocolate reduced the urinary excretion of the stress hormone cortisol and catecholamines and partially normalized stress-related differences in energy metabolism (glycine, citrate, trans-aconitate, proline, β-alanine) and gut microbial activities (hippurate and p-cresol sulfate)".

The study provides strong evidence that a daily consumption of 40 g of dark chocolate during a period of 2 weeks is sufficient to modify the metabolism of healthy human subjects, as per variation of both host and gut microbial metabolism. This was observable through the reduction of levels of stress-associated hormones and normalization of the systemic stress metabolic signatures.

The trial is published online in the ACS Journal of Proteome Research.

Source: Metabolic Effects of Dark Chocolate Consumption on Energy, Gut Microbiota, and Stress-Related Metabolism in Free-Living Subjects

http://pubs.acs.org/stoken/presspac/presspac/full/10.1021/pr900607v