Clinical Context

Accumulating evidence suggests that dietary factors, such as eating chocolate, may affect depressive symptoms. The potential mood-enhancing properties of chocolate may relate to its orosensory properties, psychoactive ingredients, and activation of neural reward pathways. However, only a few studies have analyzed associations between chocolate consumption and depressive symptoms, with conflicting results.

The goal of this analysis was to evaluate associations between chocolate consumption and depressive symptoms in a large, representative sample of US adults enrolled in the US National Health and Nutrition Examination Survey (NHANES) between 2007-2008 and 2013-2014.

Study Synopsis and Perspective

Eating dark chocolate may positively affect mood and relieve depressive symptoms, new research suggests.

However, at least 1 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 NHANES, investigators at University College London in the United Kingdom 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 with 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 news 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.

Mood Enhancer

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 2 analogs of anandamine, which produce effects similar to the cannabinoid responsible for euphoria from cannabis, and several endogenous biogenic amines. It also contains 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 with 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, those who reported any dark chocolate consumption had 70% lower likelihood of reporting clinically relevant depressive symptoms compared with those who did not eat any chocolate (odds ratio [OR], 0.30; 95% confidence interval, 0.21-0.72). However, the researchers found no significant link between any nondark chocolate consumption and clinically relevant depressive symptoms.

In models that included the amount of chocolate consumed, those in the highest quartile of chocolate intake (104-454 g/day) had 57% lower odds of depressive symptoms compared with those who reported no chocolate consumption (odds ratio, 0.43; 95% confidence interval, 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.

Inconsistent Findings

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 Dr 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 Dr Riba.

The study had no specific funding. Dr Jackson and Dr Riba have disclosed no relevant financial relationships.

Depress Anxiety. Published online July 29, 2019.^[1]

Clinical Implications

• In a large, representative sample of US adults, consumption of chocolate, and particularly dark chocolate, was linked to lower rates of clinically relevant depressive symptoms than not consuming chocolate, even after adjustment for multiple factors.
• Future longitudinal studies are needed to capture long-term chocolate intake and help to determine the direction of causality.
• Implications for the Healthcare Team : If future research shows a causal relationship and protective effect of chocolate consumption on depressive symptoms, the underlying biological mechanism needs to be clarified to identify the type and amount of chocolate consumption for optimal prevention and management of depression.