A Chocolate a Day Keeps Depression Away ?
Medscape, 13 / 09 /2019
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.
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.
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.
- The study sample consisted of 13,626 US adults aged at least 20 years who did not have diabetes and who were enrolled in NHANES between 2007-2008 and 2013-2014.
- Participants completed two 24-hour dietary recalls to determine daily chocolate consumption and the Patient Health Questionnaire to assess depressive symptoms (scores ≥10 indicating clinically relevant symptoms).
- Multivariable logistic regression controlling for sociodemographic, lifestyle, health-related, and dietary covariates allowed examination of associations of chocolate consumption (no chocolate, nondark chocolate, dark chocolate) and amount of chocolate (grams/day, in quartiles) with clinically relevant depressive symptoms.
- Relevant covariates were age, marital status, educational level, household income, weight status, chronic conditions, leisure-time physical activity, smoking status, alcohol drinking, total energy intake, and total sugar intake.
- More than one tenth (11.1%) of the sample reported any chocolate consumption, including 1.4% who reported eating dark chocolate.
- Depressive symptoms occurred in 7.6% of participants who ate no chocolate, in 6.2% of those who ate chocolate other than dark chocolate, and in 1.5% of those who ate dark chocolate.
- Consumption of nondark chocolate was not significantly associated with clinically relevant depressive symptoms.
- However, odds of clinically relevant depressive symptoms were significantly (70%) lower in those who reported eating dark chocolate (odds ratio, 0.30; 95% confidence interval, 0.21-0.72).
- Compared with participants who reported no chocolate consumption, those in the highest quartile (104-454 g/day) of chocolate consumption had 57% lower odds of depressive symptoms (odds ratio, 0.43; 95% confidence interval, 0.19-0.96) after adjustment for dark chocolate consumption.
- On the basis of their findings, the investigators concluded that consumption of chocolate, and particularly dark chocolate, may be linked to reduced likelihood of clinically relevant depressive symptoms.
- They recommend that future longitudinal studies capture long-term chocolate intake and help to determine the direction of causality.
- 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.
- Potential mechanisms by which chocolate consumption could prevent the onset of or mitigate depressive symptoms include psychoactive ingredients of chocolate; namely, 2 analogs of anandamine producing euphoric effects similar to those of cannabis and several endogenous biogenic amines including phenylethylamine, a neuromodulator implicated in mood regulation and in the pathogenesis of depression.
- Eating chocolate is a pleasurable experience that may affect several neurotransmitter systems, such as dopamine, serotonin, and endorphins, implicated in reward pathways and mood regulation.
- The richer concentration of flavonoids in dark chocolate than in other types of chocolate may be important, as flavonoids improve inflammatory profiles, and unfavorable inflammatory profiles are linked to depression onset.
- Study limitations include cross-sectional design precluding causal inferences, as depressive symptoms may lower appetite for chocolate; two 24-hour dietary recalls used to determine chocolate consumption, resulting in high potential for misclassification; the small group of dark chocolate consumers; and possible residual or unmeasured confounding.
- Randomized trials testing the effect of dark chocolate consumption on mood over a prolonged period would help elucidate this association.
- 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.