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Consumption of 85% cocoa dark chocolate improves mood in association with gut microbial changes in healthy adults: a randomized controlled trial.
Shin, JH, Kim, CS, Cha, L, Kim, S, Lee, S, Chae, S, Chun, WY, Shin, DM
The Journal of nutritional biochemistry. 2022;99:108854
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Plain language summary
Disturbances in a person’s mood interrupts their personal well-being and the ability to participate in social interactions, leading to physical health problems such as chronic diseases. The role of diet as a mood regulator has received a great deal of interest. Certain dietary components have been shown to reduce anxiety and depression and improve quality of life. The aim of this study was to investigate the effects of dark chocolate intake on mood in everyday life, with special emphasis on the gut-brain axis. This study is a randomized controlled trial. Participants who met the criteria for eligibility were randomly assigned to one of three groups: (1) control group (CON, n=14); 2) 85% cocoa chocolate group (DC85, n=18); and 3) 70% cocoa chocolate group (DC70, n=16). Results show that daily intake of dark chocolate significantly reduced negative affect in the DC85, but not in the DC70. Furthermore, gut microbial diversity was significantly higher in DC85 than the CON. Authors conclude that dark chocolate has prebiotic effects by restructuring the diversity and composition of the gut microbiome, which may in turn improve mood via the gut-brain axis.
Expert Review
Conflicts of interest:
None
Take Home Message:
- To highlight the potential benefits of high cocoa content dark chocolate in relation to mental states
- To promote more awareness of how dietary habits may impact emotional wellbeing
- To emphasise the importance of microbiota and the gut-brain axis regarding dietary habits.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Background
The authors highlight that dark chocolate has been continually identified for its effects on mood. However, there is a dearth of evidence concerning the emotional impact of daily consumption of dark chocolate. Hence, the impact of dark chocolate consumption on daily mood, focusing on the gut-brain axis, is being investigated in this study.
Objectives
- To evaluate the correlation between the effect on emotional state after consuming dark chocolate and the gut microbiota in healthy adults
- To identify alterations in the composition and diversity of the microorganisms in the gastrointestinal tract on account of dark chocolate intake.
Study Design
A randomised controlled trial was performed at Seoul National University from July to December 2017, This involved. consumption of two types of dark chocolate (70% and 85% cocoa content). Subjects in the treatment groups were blinded although investigators and the control cohort were unblinded.
Participants
117 individuals were screened. However, 48 healthy males and females aged 20-30 years were eligible at baseline.
Interventions
- Subjects (n=16): Consumed 30g/day of 70% cocoa chocolate for 3 weeks
- Participants (n=18): Consumed 30g/day of 85% cocoa chocolate for 3 weeks
- Participants (n=14): The control group consumed no chocolate for 3 weeks.
Main Health Outcomes Measured
- Mood states were quantified via the Positive and Negative Affect Schedule in tandem with Microbiota analysis pre- and post-experiment
- Body composition analysis and dietary assessment were also conducted pre- and post-intervention
- Faecal 16S rRNA sequencing analysis of bacterial genomic DNA was conducted for the cohort who consumed 85% cocoa chocolate and the control arm to evaluate the association between the mood-altering effects of dark chocolate and the gut microbiota
- Statistical tests were performed based on intention-to-treat analysis. The Chi-squared test, Kruskal-Wallis test, one-way ANOVA, unpaired t-test and Mann-Whitney U test were employed for inter-group analysis. Spearman's correlation analysis was used to assess the association between gut microbiota composition and mood scores and P<.05 was considered statistically significant.
Results
- Daily intake of dark chocolate substantially diminished negative emotional states in the cohort consuming 85% cocoa content, but not in the 70% cocoa treatment arm
- Gut microbial diversity was substantially greater in the 85% cacao cohort than the control group (P<.05)
- Blautia obeum levels were significantly elevated and Faecalibacterium prausnitzii levels were decreased in the 85% cacao cohort than the control arm (P<.05).
- Furthermore, it was observed that changes in negative affect scores were inversely correlated with diversity and relative abundance of Blautia obeum (P<.05).
Conclusions
The observations suggest that consumption of dark chocolate with a higher cocoa content may induce prebiotic effects due to its capacity to restructure the diversity and composition of the gut microbiota. Furthermore, consuming dark chocolate with a higher cocoa might exert a positive effect on negative emotional states through the gut-brain axis.
Clinical practice applications:
- To inform practitioners of the benefits of 30g/day high (85%) cocoa chocolate consumption and its potential positive impact on mood through the gut-brain axis
- To educate clients regarding the potential benefits of daily high cocoa content chocolate consumption and its possible favourable effect on emotional states associated with gut microbiota.
Considerations for future research:
- More extensive research could investigate interventions of a longer period
- Further studies could evaluate if any difference exists between cocoa and cacao consumption and emotional states via the gut-brain axis, and the strength of any associations
- Interventions could investigate which strains of bacteria that high cocoa content dark chocolate may affect.
Abstract
Dark chocolate has long been recognized for its mood-altering properties; however, the evidence regarding the emotional effects of daily dark chocolate intake is limited. Therefore, we aimed to investigate the effects of dark chocolate intake on mood in everyday life, with special emphasis on the gut-brain axis. Two different dark chocolates (85% and 70% cocoa content) were tested in this study. In a randomized controlled trial, healthy adults (20-30 y) consumed either 30 g/d of 85% cocoa chocolate (DC85, n=18); 70% cocoa chocolate (DC70, n=16); or no chocolate (control group, CON; n=14); for 3 weeks. Mood states were measured using the Positive and Negative Affect Schedule (PANAS). Daily consumption of dark chocolate significantly reduced negative affect in DC85, but not in DC70. To assess the association between the mood-altering effects of dark chocolate and the gut microbiota, we performed fecal 16S rRNA sequencing analysis for the DC85 and CON groups. Gut microbial diversity was significantly higher in DC85 than CON (P<.05). Blautia obeum levels were significantly elevated and Faecalibacterium prausnitzii levels were reduced in DC85 compared to CON (P<.05). Furthermore, we found that the observed changes in negative affect scores were negatively correlated with diversity and relative abundance of Blautia obeum (P<.05). These findings indicate that dark chocolate exerts prebiotic effects, as evidenced by its ability to restructure the diversity and abundance of intestinal bacteria; thus, it may improve negative emotional states via the gut-brain axis.
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Systematic review of the prospective association of daily step counts with risk of mortality, cardiovascular disease, and dysglycemia.
Hall, KS, Hyde, ET, Bassett, DR, Carlson, SA, Carnethon, MR, Ekelund, U, Evenson, KR, Galuska, DA, Kraus, WE, Lee, IM, et al
The international journal of behavioral nutrition and physical activity. 2020;17(1):78
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The health benefits of physical activity for people of all ages, fitness levels, and sociodemographic backgrounds are well-documented. The main aim of this study was to provide an updated description of the association between daily step counts and subsequent cardiovascular disease (CVD) morbidity or mortality, dysglycaemia, and all-cause mortality in adults and the patterns of these associations. This study is a systemic review of 17 studies from 13 different cohorts. Participants’ mean age ranged from 49.7 to 78.9 years with samples comprised of 46.9% female participants on average. Results showed that increasing steps per day is beneficial for health: taking more steps per day was associated with lower risk of all-cause mortality, and lower risk of CVD morbidity or mortality. These associations appear to hold across age, gender, and weight status. Authors conclude that this additional evidence will help guide meaningful volume targets that can be used for health care, education, and behavioural interventions, and potentially inform the development of public health guidelines for steps and health.
Abstract
BACKGROUND Daily step counts is an intuitive metric that has demonstrated success in motivating physical activity in adults and may hold potential for future public health physical activity recommendations. This review seeks to clarify the pattern of the associations between daily steps and subsequent all-cause mortality, cardiovascular disease (CVD) morbidity and mortality, and dysglycemia, as well as the number of daily steps needed for health outcomes. METHODS A systematic review was conducted to identify prospective studies assessing daily step count measured by pedometer or accelerometer and their associations with all-cause mortality, CVD morbidity or mortality, and dysglycemia (dysglycemia or diabetes incidence, insulin sensitivity, fasting glucose, HbA1c). The search was performed across the Medline, Embase, CINAHL, and the Cochrane Library databases from inception to August 1, 2019. Eligibility criteria included longitudinal design with health outcomes assessed at baseline and subsequent timepoints; defining steps per day as the exposure; reporting all-cause mortality, CVD morbidity or mortality, and/or dysglycemia outcomes; adults ≥18 years old; and non-patient populations. RESULTS Seventeen prospective studies involving over 30,000 adults were identified. Five studies reported on all-cause mortality (follow-up time 4-10 years), four on cardiovascular risk or events (6 months to 6 years), and eight on dysglycemia outcomes (3 months to 5 years). For each 1000 daily step count increase at baseline, risk reductions in all-cause mortality (6-36%) and CVD (5-21%) at follow-up were estimated across a subsample of included studies. There was no evidence of significant interaction by age, sex, health conditions or behaviors (e.g., alcohol use, smoking status, diet) among studies that tested for interactions. Studies examining dysglycemia outcomes report inconsistent findings, partially due to heterogeneity across studies of glycemia-related biomarker outcomes, analytic approaches, and sample characteristics. CONCLUSIONS Evidence from longitudinal data consistently demonstrated that walking an additional 1000 steps per day can help lower the risk of all-cause mortality, and CVD morbidity and mortality in adults, and that health benefits are present below 10,000 steps per day. However, the shape of the dose-response relation is not yet clear. Data are currently lacking to identify a specific minimum threshold of daily step counts needed to obtain overall health benefit.