Even with Chocolate, the Dose Makes the Poison, or Does It?

Just as we were getting comfortable with the idea that a daily square (or two, or three) of chocolate is good for our longevity, heart, blood vessels, etc, comes the bad news.  Too much chocolate may be linked to depression.  This is the subject of a report in the Archives of Internal Medicine.  Californian physicians set out to study the relationship between chocolate and mood. 

Over 1,000 healthy San Diego volunteers (694 men, 324 women) took part in the study.  They completed a depression scale test (the Center for Epidemiologic Studies Depression Scale (CES-D), and reported how much chocolate they ate.  

Out of the 931 subjects who were not taking anti-depressants, those who screened positive for possible depression ate an average of 8.4 servings of chocolate per month, while those with a clear positive test for depression ate 11.8 servings a month; these findings contrast with those for people with no evidence of depression, who averaged 5.4 servings a month.  These differences were statistically significant for both men and women, i.e. they did not occur by chance alone.  They were not explained by differences in consumption of fat, calories, carbohydrates, or caffeine.  

The investigators emphasize that the study's design cannot be used to determine cause-and-effect; thus it cannot indicate whether chocolate eating causes depression, depression causes stimulation of chocolate craving, or a ‘third party’ factor (e.g. inflammation) causes chocolate craving and depression.  This emphasizes the problem with many such studies that merely reveal associations at a single point of time.  However, they are usually adequate to generate hypotheses for testing in new studies.

P.S.  If you really need to know, a serving of Hershey’s, Nestle, or Mars is one bar (40 - 45 grams).