August 09, 2019
Eating dark chocolate may positively affect mood and relieve depressive symptoms, new research suggests.
However, at least one expert said that at this point, the findings, although intriguing, are no more than food for thought and should not change dietary habits.
Using data from the US National Health and Nutrition Examination Survey (NHANES), investigators at University College London in the United Kngdom found that individuals who reported eating any dark chocolate in two 24-hour periods had 70% lower odds of reporting clinically relevant depressive symptoms compared to their counterparts who reported no chocolate consumption.
"This study provides some evidence that consumption of chocolate, particularly dark chocolate, may be associated with reduced odds of clinically relevant depressive symptoms," lead author Sarah E. Jackson, PhD, said in a release.
The study, she added, is the first to examine the association between depression and the type of chocolate consumed.
The study was published online July 29 in Depression and Anxiety.
Chocolate has been widely reported to have mood-enhancing properties. Several mechanisms for a relationship between chocolate and mood have been proposed.
Chocolate contains a number of psychoactive ingredients, including two analogues of anandamine, which produce effects similar to that of cannabinoid, an agent that causes feelings of euphoria from ingesting cannabis. In addition, chocolate contains several endogenous biogenic amines, as well as phenylethylamine, a neuromodulator that is believed to be important for regulating mood, the investigators note.
To learn more, the researchers analyzed NHANES survey data from 2007 to 2008 and from 2013 to 2014. The total data set included 13,626 adults.
Daily chocolate consumption was determined from two 24-hour dietary recalls. Depressive symptoms were assessed using the Patient Health Questionnaire–9.
Among study participants, 7.6% who consumed no chocolate had depressive symptoms, compared to just 1.5% of persons who ate dark chocolate. The rate of depressive symptoms in persons who ate chocolate other than dark chocolate was 6.2%.
After adjusting for multiple factors, participants who reported any dark chocolate consumption had 70% lower likelihood of reporting clinically relevant depressive symptoms compared to those who did not eat any chocolate (odds ratio [OR], 0.30; 95% confidence interval [CI], 0.21 – 0.72). However, the researchers found no significant link between any non–dark chocolate consumption and clinically relevant depressive symptoms.
In models that included the amount of chocolate consumed, participants who were in the highest quartile of chocolate intake (104 to 454 g/day) had 57% lower odds of depressive symptoms compared with those who reported no chocolate consumption (OR, 0.43; 95% CI, 0.19 – 0.96), after adjusting for the type of chocolate consumed.
These associations were evident after adjustment for age, marital status, level of education, annual household income, weight status, chronic conditions, leisure-time physical activity, smoking status, alcohol intake, total energy intake, and total sugar intake.
These observations, the investigators note, are in line with most experimental studies, which have shown benefits of chocolate consumption for mood, at least in the short term.
However, the findings are inconsistent with those of previous surveys that have shown positive associations between chocolate consumption and depressive symptoms.
"The discrepant results may be attributable to the adjustment in the present analyses for a wide range of covariates accounting for potential confounding," the investigators write.
Further research is needed 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," said Jackson.
"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," she added.
Commenting on the findings for Medscape Medical News, Michelle Riba, MD, clinical professor and associate director, University of Michigan Comprehensive Depression Center, Ann Arbor, told Medscape Medical News, "You wouldn't hang your hat on this study in terms of telling patients to have dark chocolate. It is not that kind of study. However, looking for adjunctive treatments and what people can do to stay healthy is important.
"The problem is, if you tell someone dark chocolate is good, likely people would eat a lot of dark chocolate and not eat their fruits and veggies. For everyone, it is important to exercise and have a good, balanced diet," added Riba.
The study had no specific funding. The authors and Riba have disclosed no relevant financial relationships.