Is the consumption of chocolate good or bad for a person’s health? In my post, Rx.: Chocolate I discussed a study that suggested that a higher chocolate consumption might reduce blood pressure and the risk of heart disease.
I also pointed out the reason for the tentative wording: “suggests” . . . “might.” The study results were not generated by a controlled experiment. Rather, the results were a correlational finding. Statistically, individuals who had consumed more chocolate had an X% lower rate of heart health problems. Did one cause the other?
Happily, a commenter pointed me to a randomized, controlled trial (experiment) that found decreased blood pressure after increased chocolate consumption. Not a huge effect, but a causal effect just the same.
So chocolate is good for you!
Not so fast, sparky. Even if the “good for your cardiovascular health” finding holds up, chocolate may not be good for you in every way.
In news of a recent report published in the Archives of Internal Medicine I learned -
Individuals who screen positive for possible depression appear to consume more chocolate than those not screening positive for depression. [source]
How did the researchers determine this? Here’s how:
Natalie Rose, M.D., of University of California, Davis, and University of California, San Diego, and colleagues examined the relationship between chocolate and mood among 931 women and men who were not using antidepressants. Participants reported how much chocolate they consumed and most also completed a food frequency questionnaire about their overall diet. Their moods were assessed using a previously validated depression scale.
Those who screened positive for possible depression consumed an average of 8.4 servings of chocolate per month, compared with 5.4 servings per month among those not screening positive. Those whose scores were even higher, reflecting probable major depression, consumed even more chocolate—11.8 servings per month. [bolds mine]
Good numbers. But yes, a correlational finding. Fortunately, the researchers and the article writer included this very important paragraph, illustrating exactly why a correlational finding must be taken with a grain of salt (and not a square of Belgian dark).
Several explanations for the findings are possible, the authors note. “First, depression could stimulate chocolate cravings as ‘self-treatment’ if chocolate confers mood benefits, as has been suggested in recent studies of rats. Second, depression may stimulate chocolate cravings for unrelated reasons, without a treatment benefit of chocolate (in our sample, if there is a ‘treatment benefit,’ it did not suffice to overcome the depressed mood on average). Third, from cross-sectional data the possibility that chocolate could causally contribute to depressed mood, driving the association, cannot be excluded.”
Well done! Now that’s good, skeptical science and science reporting.
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Tags: diet, mental health
April 28th, 2010 at 8:40 am
Andrew–
About chocolate I have little to say, especially since I, too, live in Florida, which means key lime pie, not other, lesser confections.
But reading your comment at Mature Landscaping and your mention of Charlie Crist’s veto, I thought you might be interested in my Monday post at Drinks Before Dinner, titled “First, let’s hang all the teachers.” All the high-minded talk about improving education is so much bunk. What I’m convinced is actually going on is what I take up.
April 28th, 2010 at 11:05 am
Thank’s Barry, I’ll check it out.