Is chocolate good for you? by Katy Stuart RD
As it is soon to be Valentine’s Day, I thought I would delve into the world of chocolate and see what evidence there is for some of the health benefits that have been claimed in the recent past.
As a bit of background, chocolate is made from Theobroma Cacao beans grown in tropical zones around the equator, where climate conditions are well suited, such as Central and South America, Southeast Asia and West Africa.(1) The cacao pods are harvested by hand and the pulp and the beans are scooped out of the pods for the fermentation stage.(1) Fermentation changes the texture of the beans and gets rid of the mucilage. The beans are then dried and roasted.(1,2) During roasting, the beans are sterilised and the flavour is developed.(1,2) After that, the beans are ‘winnowed’ to remove the husks and dust particles, leaving behind the cacao ‘nibs.’(1)
Next, the beans are cracked in a cacao crusher and the shells are removed. Sugar is then added (cacao nibs are naturally bitter). They are then slowly heated and cooled, which allows the fats to crystallise and the chocolate to be firm, smooth and able to be broken up.(1) The heated mixture is poured into moulds and cooled, then packaged and shipped off to be sold.(1,2)
Of course, a wide range of chocolate products is available, and manufacturers add many other ingredients, such as milk, butter, fat, vegetable oils and artificial colours and flavours.(3) White chocolate doesn't contain any cocoa solids and is made up of cocoa butter, sugar and milk.(3) Dark chocolate is the so-called ‘healthier’ of the chocolate types(5) and varies in its percentage of cocoa solids from 50-90%. The higher the percentage the darker the chocolate is.(3) Milk chocolate tends to be higher in sugar and fat but also contains nutrients, such as protein, and small amounts of minerals, such as iron, zinc, copper, potassium, phosphate, magnesium and B12.(4,6) Chocolate also contains caffeine; the highest amount is found in dark chocolate, where 100g of 70-80% dark chocolate has 80mg of caffeine, similar to a cup of coffee.(5,6)
Dark chocolate contains antioxidants including polyphenols and flavonols, e.g. epicatechin.(7,8 ) Polyphenols and flavonols can reduce inflammation and protect against cell damage from free radicals.(7) It is thought that flavonols can help improve heart health and the immune system, lower cancer risk, reduce blood pressure, increase cognitive function, boost athletic performance and reduce stress.(7,9,10,11)
Cocoa - What does the research tell us?
The origin of the evidence linking cocoa beans and heart health is based on studies of the Kuna people living on the islands off the coast of Panama. They regularly consume large amounts of cocoa as a hot chocolate drink, and it was noted they had much lower rates of heart disease.(9) This finding led to a huge interest in exploring the usage of cocoa supplements to treat/prevent cardiovascular conditions.(9,12,13)
The Cocoa Supplement and Multivitamin Outcomes Study (COSMOS, 2019-2022) aimed to investigate these health claims with its large-scale research using cocoa supplements. Published results from the study showed cocoa extract supplementation significantly reduced total cardiovascular events by 15% and reduced deaths due to cardiovascular disease by 27% in the participants studied, which is a fascinating finding.(13)
Due to the possible effects of cocoa on blood flow, another area where scientists think that cocoa can benefit is the brain, specifically helping to prevent cognitive decline in older adults.(9) However, according to the COSMOS trial results, the cocoa extract supplementation did not show improvement in cognition at one year or across all three years of follow-up participants.(13) The investigators think that baseline nutritional status may play a role in these findings.(13)
Also, the methylxanthines in chocolate (caffeine and theobromine) have psychoactive properties and may affect cognitive function and mood.(14) This may explain the phenomenon of craving chocolate when our mood is low and why some people say they are ‘addicted’ to chocolate.
Another interesting area is the role that flavonols may play in the development of diabetes.(5,9,15,16) Natural polyphenol-rich products are theorised to modulate carbohydrate metabolism by restoring β-cell integrity and improving the insulin-releasing activity and glucose uptake.(16) Cocoa and cocoa flavonoids may impact the pathophysiological mechanisms involved in insulin resistance and endothelial dysfunction, theoretically reducing the risk of cardiometabolic diseases.(16) A large study from 2016 found that people who eat chocolate, including dark chocolate, at least once a week had a lower prevalence of diabetes and were at lower risk for diabetes four to five years later.(15)
What about gut health?
Well, cocoa is also known to be a prebiotic and dark chocolate flavonols may improve gastrointestinal function.(7,8) A small study from 2011 on 22 subjects showed statistically significant reductions in plasma triacylglycerol and C-reactive protein, as well as a reduction in clostridia and an increase in the ‘good’ bacteria bifidobacteria and lactobacilli.(7)
However, overall, the jury is out about promoting regular consumption of dark chocolate. Unfortunately, high-quality evidence is still lacking.(17) The type of chocolate, the amount of chocolate, what else study participants were eating and other associated risk factors for heart and circulatory diseases, all need to be considered.(18) Chocolate products do not normally indicate their flavonol content and darker or higher % cacao chocolate does not necessarily mean a higher flavonol content.(16) Many of the flavonols are removed during the manufacturing process.(19) You would likely not be able to consume high enough amounts of flavonols (that were used in studies such as the COSMOS trial) from chocolate alone, at least without increasing your fat and sugar consumption.(9, 10,12) There are other foods containing flavonols such as apples, berries, beans and pulses, as well as tea, which can be incorporated into our diets instead.(9)
Chocolate is a high-energy food and too much can result in excess weight, which is a risk factor for cardiovascular disease.(18)
END NOTE
There are certainly some interesting theories and some low to moderate evidence out there about the health benefits of chocolate, specifically dark chocolate, and I am sure the chocolate manufacturers have also found this interesting too! However, definitive evidence is sadly not there. You are better off following a healthy diet with plenty of fruit, vegetables and wholegrains. Chocolate is fine as an occasional treat and certainly can be enjoyed on Valentine’s day, especially in a heart-shaped box from your true love!
Katy has 20 years of experience in both acute nutrition support and renal dietetics. she is now a full-time Renal Dietitian at Pilgrim Hospital,
Boston, Lincs.
Katy Stuart, RD, Renal Dietitian
References
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Harvard School Of Public Health, Nutrition Source, Dark Chocolate (2023). https://nutritionsource.hsph.harvard.edu/food-features/dark-chocolate/
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Lee H, Colin K, Asmaa A, Kroon P, Cohn S, Rimm E, Aedin C (2012). Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: a systematic review and meta-analysis of randomised trials, American Journal of Clinical Nutrition, Vol 95, (3):740-751. https://www.sciencedirect.com/science/article/pii/S0002916523026928
Cocoa Supplement and Multivitamin Outcomes Study (2022). https://cosmostrial.org/results/
Scholey A and Owen L (2013). Effects of chocolate on cognitive function and mood: a systematic review, Nutrition Reviews. https://mindmarbles.com.au/wp-content/uploads/Effects-of-chocolate-on-cognitive-function-and-mood_a-systematic-review.pdf
Abbott, Dark Chocolate and Diabetes: The benefits of this tasty snack, 2017. https://www.abbott.com/corpnewsroom/diabetes-care/dark-chocolate-and-diabetes.html#:~:text=The%20Link%20Between%20Dark%20Chocolate%20and%20Diabetes&text=Polyphenols%20in%20dark%20chocolate%20may,had%20decreased%20fasting%20blood%20sugar.
Grassi D, Giovambattista D, Mai F, Leitizia M, De Feo M, Soddu D, Fellini E, Veneri M (2015), Cocoa, Glucose Tolerance, and Insulin Signaling: Cardiometabolic Protection, ACS Publications. https://pubs.acs.org/doi/10.1021/acs.jafc.5b00913
Tan T, Lim X, Yeo J, Lee S, Lai N (2021). The Health Effects of Chocolate and Cocoa: A Systematic Review, Nutrients. 2021 Aug 24;13(9):2909. https://pmc.ncbi.nlm.nih.gov/articles/PMC8470865/
British Heart Foundation, 8 Chocolate ‘Facts’ you shouldn’t believe (2015). https://www.bhf.org.uk/informationsupport/heart-matters-magazine/nutrition/chocolate-myths
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