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Article by: Chiraz Guessaier, PhD

Dark chocolate – A delicious treat for bad mood


2-Minute Read - October 26, 2021


If you’ve ever fancied eating chocolate every day, now is your chance to seize the dream!  


Chocolate in general, and dark chocolate in particular, is a good source of antioxidants and is rich in fiber, iron, magnesium, and other essential minerals. But more interestingly, we now know that the benefits of dark chocolate extend to mood modulation and improvement; and dark chocolate could be a feasible antidote to poor mood states. [1,2,3

Textbox for Chocolate Blog-3



A recent research study by Shin et al. (2018) focused on the connection between our gut  microbiome and our brain, providing evidence that “dark chocolate consumption in everyday life influences physiological and psychological states. These results suggest 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.” [4


The role of diet in regulating mood has gained traction, as certain dietary components have been shown to reduce mood disturbances and improve the overall quality of life. Although we know that cocoa in dark chocolate contains polyphenol, a nutritional compound that affects mood [5], we do not know much about the emotional impact of consuming dark chocolate in everyday life. We also do not know how underlying gut molecular changes trigger mood alterations.  


That’s why researchers in this study turned their attention to studying the diversity and composition of gut microbial communities and their impact on mood states, by collecting fecal samples from 48 participants, using DNAGenotek®’s OMNIgene•GUT kit; and performing fecal 16s rRNA sequencing analysis.  


Results of the study 


Daily intake of higher-cocoa dark chocolate (85%) significantly reduced negative emotions compared to lower-cocoa dark chocolate (70%), suggesting that the effects of cocoa on brain function differ depending on the dose of cocoa administered. [6, 7] 


In addition, the daily intake of 85% dark chocolate increased gut microbial community diversity and composition, by reducing the ratio of harmful bacteria (Firmicutes and Bacteroidetes) to beneficial ones. [8, 9] 


The study is also aligned with previous findings that high gut-microbial diversity and composition, that occurs as a result of routine consumption of dark chocolate, positively affects the emotional wellbeing of healthy adults. [10, 11] The authors propose that the mood-altering effect of the 85% dark chocolate may be mediated by the very changes in the diversity and abundance of intestinal bacteria.  

 “Collectively, given the role of the gut microbiota in polyphenol bioavailability and metabolism as well as brain function, the findings suggest that daily intake of polyphenol-rich chocolate gradually alters gut microbial diversity, resulting in beneficial impacts on the host’s mood.” [4] 

It’s worth mentioning that this is the first study which offers evidence that dark chocolate consumption in everyday life influences physiological and psychological states. This evidence suggests that dark chocolate has prebiotic effects that occur by restructuring the diversity and composition of the gut microbiome, which may in turn improve mood states through the gut-brain axis.  


This post was based on research work undertaken by a multi-disciplinary team of researchers from Seoul National University in the Republic of Korea. The research was supported by the National Research Foundation of Korea and Chungnam National University. 


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[1] Q Huang, H Liu, K Suzuki, S Ma, C. Liu. Linking what we eat to our mood: a review of diet, dietary antioxidants, and depression. Antioxidants (Basel), 8 (2019) 

[2] A Scholey, L. Owen. Effects of chocolate on cognitive function and mood: a systematic review. Nutr Rev, 71 (2013), pp. 665-681 
[3] Smith. Benefits of flavanol-rich cocoa-derived products for mental well-being: a review. J Funct Foods, 5 (2013), pp. 10-15 
[4] JH Shin, CS Kim , L Cha , et al. Consumption of 85% cocoa dark chocolate improves mood in association with gut microbial changes in healthy adults: a randomized controlled trial. The Journal of Nutritional Biochemistry, Volume 99, 2022 
[5] F Cardona, C Andrés-Lacueva, S Tulipani, FJ Tinahones Queipo-Ortuño MI. Benefits of polyphenols on gut microbiota and implications in human health. J Nutr Biochem, 24 (2013), pp. 1415-1422 
[6] D Camfield, A Scholey, A Pipingas, R Silberstein, M Kras, K Nolidin, et al. Steady state visually evoked potential (SSVEP) topography changes associated with cocoa flavanol consumption. Physiol Behav, 105 (2012), pp. 948-957 
[7] MP Pase, AB Scholey, A Pipingas, M Kras, K Nolidin, A Gibbs, et al. Cocoa polyphenols enhance positive mood states but not cognitive performance: a randomized, placebo-controlled trial. J Psychopharmacol, 27 (2013), pp. 451-458 
[8] C Mu, Y Yang, W. Zhu Gut Microbiota: The Brain Peacekeeper. Front microbiol, 7 (2016), p. 345 
[9] S Hu, Y Fang, CH Ng, JJ. Mann. Involvement of neuro-immune mechanism and brain–gut axis in pathophysiology of mood disorders. Front Psychiatr (2019), p. 10 
[10] D Serra, LM Almeida, TC. Dinis. Dietary polyphenols: A novel strategy to modulate microbiota-gut-brain axis. Trends food sci technol, 78 (2018), pp. 224-233 
[11] S Filosa, F Di Meo, S. Crispi. Polyphenols-gut microbiota interplay and brain neuromodulation. Neural regeneration research, 13 (2018), p. 2055 


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