Dark chocolate as a remedy for emotional stress receives new support from a clinical trial published online in ACS’ Journal of Proteome Research: Gut Microbiota, and Stress-Related Metabolism in Free-Living Subjects. Men and women who ate just over an ounce and a quarter of dark chocolate a day for two weeks showed reduced levels of stress hormones in their bodies. Dark chocolate consumption also partially corrected other stress-related biochemical imbalances.
Sunil Kochhar and colleagues note growing scientific evidence that antioxidants and other beneficial substances in dark chocolate may reduce risk factors for heart disease and other physical conditions. Studies also suggest that chocolate may ease emotional stress. Until now, however, there was little evidence from research in humans on exactly how chocolate might have those stress-busting effects.
In the study, scientists identified reductions in stress hormones and other stress-related biochemical changes in volunteers who rated themselves as highly stressed and ate dark chocolate for two weeks.
The study found that 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, beta-alanine) and gut microbial activities (hippurate and p-cresol sulfate)."
“The study provides strong evidence that a daily consumption of 40 grams [1.4 ounces] during a period of 2 weeks is sufficient to modify the metabolism of healthy human volunteers,” the scientists say.
This study takes a wide, ambitious overall view of effects of nutrients on human health. Citing multiple references, the authors write:
The sheer complexity of a food matrix, such as dark chocolate, may determine a large variety of effects on the metabolism. Many studies have indeed demonstrated the potential health implications of dark chocolate constituents, but rarely as a whole product. For instance, cocoa is rich in flavonoids . . . which were associated with benefits on cardiovascular health by maintaining low blood pressure, improving endothelial function, and by reducing thrombotic state, oxidative and inflammatory states. Benefits of cocoa on improvement of insulin sensitivity and glucose tolerance were also reported. Other biochemically active molecules naturally occurring in chocolate include theobromine, a bitter alkaloid also known to reduce blood pressure, phenylethylamine, a monoamine alkaloid which can act as neurotransmitter, and N-oleoyl- and N-linoleoyl-ethanolamine that slow the rate of anandamide breakdown, a brain neurotransmitter. Therefore, if there is growing evidence on the health benefits associated with chocolate, mechanisms of action of chocolate bioactive components at the molecular levels are poorly understood. This is particularly the case for benefits related to brain health and improvement of stress states where only symptomatic data, such as brain blood flow, are available
The take home message from this study is that people who felt anxious and stressed and who ate just over an ounce of dark chocolate a day, felt better. Changes in their metabolism and in hormones in their urine supported the notion that what made the difference was not just a panacea but the dark chocolate.