One need only look at the recent introduction of chocolate Cheerios to fully grasp Americans' fondness for the pulp from cacao beans. Savoring chocolate is normal.
But, researchers said Monday, overindulging in it could be a marker for depression.
Researchers at UC San Diego and UC Davis examined chocolate consumption and other dietary intake patterns among 931 men and women who were not using antidepressants. The participants were also given a depression screening test. Those who screened positive for possible depression consumed an average of 8.4 servings of chocolate — defined as one ounce of chocolate candy — per month. That compared with 5.4 servings per month among people who were not depressed.
Those who scored highest on the mood tests, indicating possible major depression, consumed an average of 11.8 servings per month. The findings were similar among women and men.
When the researchers controlled for other dietary factors that could be linked to mood — such as caffeine, fat and carbohydrate intake — they found only chocolate consumption correlated with mood.
It's not clear how the two are linked, the authors wrote. It could be that depression stimulates chocolate cravings as a form of self-treatment. Chocolate prompts the release of certain chemicals in the brain, such as dopamine, that produce feelings of pleasure.
There is no evidence, however, that chocolate has a sustained benefit on improving mood. Like alcohol, chocolate may contribute a short-term boost in mood followed by a return to depression or a worsened mood. A study published in 2007 in the journal Appetite found that eating chocolate improved mood but only for about three minutes.
It's also possible that depressed people seek chocolate to improve mood but that the trans fats in some chocolate counteract the effect of omega-3 fatty acid production in the body, the authors said in the paper. Omega-3 fatty acids are thought to improve mental health.
Another theory is that chocolate consumption contributes to depression or that some physiological mechanism, such as stress, drives both depression and chocolate cravings.
"It's unlikely that chocolate makes people depressed," said Marcia Levin Pelchat, a psychologist who studies food cravings at the Monell Chemical Senses Center in Philadelphia. She was not involved in the new study. "Most people believe the beneficial effects of chocolate are on mood and that they are learned. You eat chocolate; it makes you feel good, and sometime when you're feeling badly it occurs to you, ‘Gee, if I eat some chocolate I might feel better.' "
Chocolate is popular in North America and Britain, she said. But in other cultures, different foods are considered pleasure-inducing pick-me-ups.
"In the United States, people consider chocolate really tasty," Pelchat said. "It has a high cultural value. It's an appropriate gift for Valentine's Day. But in China, you might give stuffed snails to someone you really like."