1st Revision: 
2nd Revision: What we need to know about dark chocolate
Dark chocolate, containing more than 70% of cocoa solids, has been scientifically proven to be beneficial for our health as it contains important micronutrients including potassium, iron, magnesium and zinc. Dark chocolate also contains flavonoids and antioxidants as naturally occuring chemicals caffeine and theobromine.
The quality and quantity of cocoa solids in the chocolate is important. Seventy percent is the absolute minimum percentage of cocoa in dark chocolate, and ideally a higher percentage is better.1
Benefits of dark chocolate to the heart2
- Blood Pressure - Flavonoids in dark chocolate have been shown to stimulate the lining of arteries to produce nitric oxide. Nitric oxide sends signals to the arteries to relax which mildly lowers the blood pressure. However, people already undergoing treatment may not benefit from these effects as blood pressure medications have a more potent effect
- Cholesterol - dark chocolate raises HDL (high density lipoprotein) and lowers LDL (low density lipoprotein) - Compounds in dark chocolate may reduce LDL , high levels of which are associated with increased risk of cardiovascular disease. Some LDLs are more likely to oxidize which may cause a harmful reaction with tissue in your body
- Insulin resistance3- Flavonoids in dark chocolate may also reduce insulin resistance, which is a clinical sign of type 2 diabetes
Nutritional components of dark chocolate4 (with 70-85% of cocoa solids)
Nutritional Value per 100 g
| Component | Content | % DV |
| Calories | 605 kcal | 30 |
| Fat | 43.1 g | 66 |
| Carbohydrate | 46.3 g | 15 |
| Protein | 7.9 g | 16 |
| Potassium | 722 mg | 21 |
| Sodium | 20.2 mg | 1 |
| Magnesium | 230 mg | 58 |
| Iron | 12 mg | 67 |
| Zinc | 3,3 mg | 22 |
| Copper | 1.8 mg | 89 |
| Caffeine | 80 mg | - |
| Theobromine | 810 mg | - |
How often and how much to eat5
Although loaded with nutrients, dark chocolate is calorically dense, which means it is easy to overeat. Therefore, you should eat dark chocolate in moderation. Twenty-five grams (roughly 2 squares) per day would allow you to benefit from this food without risking overeating. There is no right or wrong time to consume dark chocolate, however, due to such stimulant chemicals as caffeine and theobromine. So, it is probably a good idea to consume it before exercise or during the middle of the day as these chemicals can increase wakefulness, alertness, and athletic performance. Dark chocolate can be enjoyed daily but moderation is key.
Other benefits of dark chocolate6
- Nutritious - Dark chocolate is very rich in important micronutrients as mentioned above. . These micronutrients help the immune system, metabolism, muscles and nerves. It also contains a good amount of soluble fibers that helps lower blood cholesterol levels
- Antioxidant - The antioxidant capabilities of food are measured by its ORAC value. This stands for Oxygen Radical Absorbance Capacity. As proved in some studies, dark chocolate does well in this area as it is rich in antioxidants. However, some other studies show different values; which makes evidence controversial. The compounds responsible for this antioxidant effect are: polyphenols, flavonoids and catechins. One study comparing the antioxidant effect of dark chocolate to that of fruits known for their antioxidant effects such as acai and 0blueberries, showed that dark chocolate had a more powerful antioxidant effect
- Brain Function - The boost in brain function is likely due to a number of reasons. Firstly, flavanols have been shown to improve blood flow to the brain. Secondly, dark chocolate contains caffeine and theobromine which are known to improve brain function
- Mood - Caffeine and theobromine have been shown to improve mood by boosting levels of dopamine and serotonin in the brain, which can result in an aphrodisiac-like effect, improving mood and libido
Athletic Performance: The studies suggest that dark chocolate enhances athletes' performance in fitness training. Research proved that following dark chocolate eating, the riders cycling at a moderate pace, used less oxygen and they further cycled in a flat-out-time trial.
Summary
There is a large amount of scientific evidence that cocoa provides profound health benefits that, among other effects, are particularly related to heart health.
Dark chocolate is calorically dense, so it should be consumed in moderation. When picking chocolate to eat, choose products with at least 70-85% cocoa solids. White and milk chocolates provide far less nutrition and more sugar.
References
- Francene M Steinberg, Monica M Bearden, Carl L Keen. Cocoa and chocolate flavonoids: Implications for cardiovascular health. Journal of the American Dietetic Association 2023; 103(2): 215-23. Available at: Sci-Hub | Cocoa and chocolate flavonoids: Implications for cardiovascular health | 10.1053/jada.2003.50028 (hkvisa.net)
- Desch S, Kobler D, Schmidt J, Sonnabend M, et al. Low vs. Higher-Dose Dark Chocolate and Blood Pressure in Cardiovascular High-Risk Patients. JO Am J Hypertens 2010; 23(6): 694 -700. Available at: Low vs. Higher-Dose Dark Chocolate and Blood Pressure in Cardiovascular High-Risk Patients (silverchair.com)
- Sharmistha S, Tanmay S, Runu C, et al. Dark chocolate: An overview of its biological activity, processing, and fortification approaches. Curr Res Food Sci. 2022; 5: 1916-43. Available at: Dark chocolate: An overview of its biological activity, processing, and fortification approaches (sciencedirectassets.com)
- Corina Z, and Otelea MR. Dark Chocolate: To Eat or Not to Eat? A Review. JO J AOAC Int 2019; 102(5): 1388-96 Available at: jaoac1388.pdf (silverchair.com)
- Matsumoto C, Tomiyama H, Kimura K, et al. Modulation of blood pressure-lowering effects of dark chocolate according to an insulin sensitivity-randomized crossover study. Hypertens Res 2020; 43: 575–578. Available at: Modulation of blood pressure-lowering effects of dark chocolate according to an insulin sensitivity-randomized crossover study | Hypertension Research (nature.com)
- Shiina K, Tomiyama H, Matsumoto C, Oba C, et al. Gender difference in the effects of cacao polyphenols on blood pressure and glucose/lipid metabolism in prediabetic subjects: a double-blinded, randomized, placebo-controlled crossover trial. Hypertension Res. 2019;42:1083-5.Available at: Sci-Hub | Gender difference in the effects of cacao polyphenols on blood pressure and glucose/lipid metabolism in prediabetic subjects: a double-blinded, randomized, placebo-controlled crossover trial | 10.1038/s41440-019-0208-8 (hkvisa.net)
