With Valentine's Day just around the corner, there may be another important reason for giving your loved ones chocolate besides the traditional romantic one.

According to the article, "New Evidence That Dark Chocolate Helps Ease Emotional Stress," published online in the Nov. 12, 2009 issue of Medical News Today, the "chocolate cure" for emotional stress is getting new support from a clinical trial published online in the American Chemical Society's Journal of Proteome Research: "Metabolic Effects of Dark Chocolate Consumption on Energy, Gut Microbiota, and Stress-Related Metabolism in Free-Living Subjects."

The American Chemical Society's study found that eating about an ounce and a half of dark chocolate a day for two weeks reduced levels of stress hormones in the bodies of people feeling highly stressed. Interestingly the study found that dark chocolate partially corrected other stress-related biochemical imbalances.

According to the press release, Sunil Kochhar and colleagues looked at growing scientific evidence that antioxidants and various other substances in dark chocolate may reduce risk factors for heart disease and other physical conditions. But consumers want to know what other substances and how does each substance work to balance health and reduce the risk of coronary diseases and emotional risk factors?

The latest study suggested that chocolate may ease emotional stress. But how does dark chocolate reduce stress? What exactly is the evidence?

The most recent study 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 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.

According to the study's abstract:

"Dietary preferences influence basal human metabolism and gut microbiome activity that in turn may have long-term health consequences. The present study reports the metabolic responses of free living subjects to a daily consumption of 40 g of dark chocolate for up to 14 days. A clinical trial was performed on a population of 30 human subjects, who were classified in low and high anxiety traits using validated psychological questionnaires.

Biological fluids (urine and blood plasma) were collected during 3 test days at the beginning, midtime and at the end of a 2 week study. NMR and MS-based metabonomics were employed to study global changes in metabolism due to the chocolate consumption. Human subjects with higher anxiety trait 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 free living and healthy human subjects, as per variation of both host and gut microbial metabolism."