- Cacao has been prized since at least 450 BC by ancient civilizations.
- Chocolate contains a potent blend of psycho- and biologically-active chemicals.
- While chocolate is reputed to have a range of health benefits, evidence, while enticing, is limited.
- Some forms of chocolate appear to have short-term benefits on mood and anxiety, but longer-term effects remain unclear.
By Grant H Brenner
Chocolate is one of the world’s most iconic foods. With origins in Central and South America, cacao was first enjoyed as a fermented drink as early as 450 BC. In his book The History of Money (1997), anthropologist Jack Weatherford discusses the important role cacao beans played in Aztec culture, where they were seen as a gift from the god Quetzacoatl.
New research shows that due to the presence of many psychoactive compounds, chocolate has measurable effects on the brain. It appears to be a quick short-term fix for depression and anxiety. Its longer-term benefits remain unclear.
Macabre to modern ears, fungible cacao beans were used as an early form of Aztec currency to even out differences in value of choice products of human sacrifice, as well as in more prosaic forms of trade. Like the Titan Prometheus, who in Greek mythology gives fire to humanity in defiance of the other gods, Quetzacoatl is fabled to have bequeathed upon us the forbidden magic of cacao. We've never been the same since.
Chocolate in modern times
Toward the end of his life at the beginning of the 1500s, Christopher Columbus brought chocolate to Europe, where it was used medicinally, later becoming (with a bit of sugar) a favorite of the Spanish court, one of the many commodities driving the slave trade. It was not until the Industrial Revolution, however, that modern chocolate production provided the mechanical and chemical tools to mass-produce chocolate, setting the stage for our modern love affair with this dark treat.
There are many myths about chocolate, and some science. Chocolate of course is used widely in desserts, and shares a treasured place in childhood and literature, as embodied in the rich imagery of Dahl’s beloved Charlie and the Chocolate Factory—where chocolate remains associated with prosperity.
Chocolate plays a sweet role in romantic rituals, and is often described as having an aphrodisiac effect (after the Greek goddess of love, Aphrodite). More recently, cacao has been considered a “super food,” with antioxidant, anti-inflammatory, mood-enhancing, and other purported desirable properties.
How does chocolate affect the brain?
Data on the the psychological effects of chocolate, while limited, holds promise, according to the authors of a recent study (2021) in Critical Reviews in Food Science and Nutrition. They note that cacao, the seed of the Theobroma cacao tree, has many biological compounds, some of which are altered by processing.
They include fatty acids, vitamins, and, notably, polyphenol flavonoids, bitter plant chemicals with potential broad health benefits from preventing heart disease and cancer to improving brain function. There are methylxanthines, including theobromine and caffeine, which have psychological effects, including stimulation, increased alertness, and mood enhancement, and biogenic amines, similar to brain-signaling neurotransmitter molecules such as serotonin and tryptophan (associated with mood improvement and anxiety-reduction), and tyramine (a precursor of dopamine, the “reward neurotransmitter”) among a host of others.
Chocolate’s potential health benefits are variable, due in part to the form in which chocolate is taken, how processing may affect the composition, and how the addition of other components may offset benefits. For example, adding sugar and saturated fats offsets health benefits.
In order to focus on understanding the potential psychological benefits of cacao, researchers Fusar-Poli, Aguglia, and colleagues conducted a systematic review and meta-analysis of the existing high-quality literature on how cacao changes depression, anxiety and mood. Following standard PRISMA (Preferred Reporting for Systematic Reviews and Meta-Analysis), they scoured the literature for all research on cacao’s psychological impact.
Of an original 874 publications, a total of none articles were of sufficient quality and relevance to be included in the final analysis. The rest were excluded for various reasons, including having vague outcome measures, problematic methodology (such as lacking comparison groups), and similar issues rendering the results suspect.
The researchers found that consuming cacao-rich products does indeed have a significant association with improved depression symptoms, reduced anxiety, lower negative emotion and heightened positive emotion, with a respectable medium effect size for those outcomes.
Studies of short-term consumption of dark chocolate for a few days showed improvement in anxiety and depression ratings, moderate for depression and large for anxiety. Over a longer time frame, positive emotion was improved, but reductions in negative emotion were not as durable.
The continuing story of cacao as a nutraceutical
Most of the studies were of short duration, highlighting the need for longer-term, well-designed studies to understand how to maximize chocolate’s benefits. In addition, because there are so many different ways to consume chocolate, research is needed on what types of chocolate and which of the many biologically active components of chocolate have which effects. Furthermore, it’s likely that they work in concert—chocolate is a cocktail of neurobiologically significant chemicals that synergistically produce the signature buzz we have come to crave.
The authors of the study point out that other properties of modern chocolate may also affect mood, including pleasure from eating, and sweetness. I’d add the psychological power of associations with love, the placebo effect stemming from all the lore of chocolate over the millennia, the social and cultural meanings of chocolate, and related factors distinct from the basic nutraceutical properties. The findings are based on studies using dark chocolate, which is higher in bioactive compounds than milk chocolate and lower in potentially detrimental ingredients including sugar, chemical additives, and non-cacao fat content.
Research would have to compare real chocolate with an indistinguishable substitute to tease out the placebo and symbolic effects, for example. Likewise, comparing real chocolate with a chocolate-based supplement in capsules also would help to distinguish biological from psychological factors. Clinical research looking at whether cacao is a useful adjunct to current psychiatric treatment is required to show whether chocolate has a role in treating depression, anxiety, and other psychiatric conditions.
In the meantime, the research suggests that chocolate has useful short-term benefits for mood and anxiety and may be a good addition to a thoughtful health and wellness routine. There's less clear long-term benefits, with the suggestion that cacao may boost positive emotions.
Because not all chocolate is created equal, make sure to do your own research, and consult with a health or nutrition professional as part of designing the best wellness lifestyle for you. Regardless of the health benefits, for many chocolate remains a beloved treat, a daily indulgence, even an obsession.
Laura Fusar-Poli, Alberto Gabbiadini, Alessia Ciancio, Lucia Vozza, Maria Salvina Signorelli & Eugenio Aguglia (2021): The effect of cocoa-rich products on depression, anxiety, and mood: A systematic review and meta-analysis, Critical Reviews in Food Science and
Nutrition, DOI: 10.1080/10408398.2021.1920570
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