People who eat dark chocolate less likely to be depressed

The study, published in Depression and Anxiety, is the first to examine the association with depression according to the type of chocolate consumed.

Researchers from UCL worked in collaboration with scientists from the University of Calgary and Alberta Health Services Canada and assessed data from 13,626 adults from the US National Health and Nutrition Examination Survey. Participants' chocolate consumption was assessed against their scores on the Patient Health Questionnaire, which assesses depressive symptoms.

In the cross-sectional study, a range of other factors including height, weight, marital status, ethnicity, education, household income, physical activity, smoking and chronic health problems were also taken into account to ensure the study only measured chocolate's effect on depressive symptoms.

After adjusting for these factors, it was found that individuals who reported eating any dark chocolate in two 24-hour periods had 70 per cent lower odds of reporting clinically relevant depressive symptoms than those who reported not eating chocolate at all. The 25 per cent of chocolate consumers who ate the most chocolate (of any kind, not just dark) were also less likely to report depressive symptoms than those who didn't eat chocolate at all. However researchers found no significant link between any non‐dark chocolate consumption and clinically relevant depressive symptoms.

Depression affects more than 300 million people worldwide, according to the World Health Organisation, and is the leading global cause of disability.

Lead author Dr Sarah Jackson (UCL Institute of Epidemiology & Health Care) said: "This study provides some evidence that consumption of chocolate, particularly dark chocolate, may be associated with reduced odds of clinically relevant depressive symptoms.

"However further research is required to clarify the direction of causation -- it could be the case that depression causes people to lose their interest in eating chocolate, or there could be other factors that make people both less likely to eat dark chocolate and to be depressed.

"Should a causal relationship demonstrating a protective effect of chocolate consumption on depressive symptoms be established, the biological mechanism needs to be understood to determine the type and amount of chocolate consumption for optimal depression prevention and management."

Chocolate is widely reported to have mood‐enhancing properties and several mechanisms for a relationship between chocolate and mood have been proposed.

Principally, chocolate contains a number of psychoactive ingredients which produce a feeling of euphoria similar to that of cannabinoid, found in cannabis. It also contains phenylethylamine, a neuromodulator which is believed to be important for regulating people's moods.

Experimental evidence also suggests that mood improvements only take place if the chocolate is palatable and pleasant to eat, which suggests that the experience of enjoying chocolate is an important factor, not just the ingredients present.

While the above is true of all types of chocolate, dark chocolate has a higher concentration of flavonoids, antioxidant chemicals which have been shown to improve inflammatory profiles, which have been shown to play a role in the onset of depression.