The purpose of this study was to investigate the metabolic effects of the consumption of dark chocolate. All participants were initially classified as being low or highly anxious, on the basis of their responses to a questionnaire assessing anxiety levels. Subsequently, participants were exposed to a two-week dietary intervention where they consumed 20 grams of dark chocolate, twice a day (morning snack and afternoon snack). Blood and urine samples were collected before, during (after one week) and at the end (after two weeks) of the dietary intervention. The results of the study show, amongst others, that the secretion of urinary metabolites of cortisol and catecholamines, two major categories of stress hormones, was lower following the consumption of dark chocolate in people who reported high levels of anxiety.
Title: Metabolic Effects of Dark Chocolate Consumption on Energy, Gut Microbiota, and Stress-Related Metabolism in Free-Living Subjects
Authors: Francois-Pierre J. Martin, Serge Rezzi, Emma Peré-Trepat, Beate Kamlage, Sebastiano Collino, Edgar Leibold, Jürgen Kastler, Dietrich Rein, Laurent B. Fay, Sunil Kochhar
Journal: Journal of Proteome Research (2009) vol. 8(12), pp. 5568-5579.