Dark chocolate is one of life’s true pleasures, and if you have high blood pressure, you can continue eating it as long as it provides at least 70% cocoa solids. Dark chocolate rightly deserves the name of ‘super’ food. Not only does it taste good, but it contains similar antioxidant flavonoids to those that give green tea its heart-health benefits.
Dark chocolate and blood pressure
Research published in the British Medical Journal back in 2004 suggested that a regular intake of seven foods, which included 100g dark chocolate (along with fish, fruit, vegetables, almonds, garlic and 150ml wine) could cut the risk of cardiovascular disease by as much as 76%. The scientists predicted this could increase average life expectancy by six and a half years for men, and five years for women.
The researchers were criticised for including dark chocolate instead of olive oil, but they found clear evidence that eating 100g dark chocolate per day could reduce blood pressure by an average of 5.1/1.8 mmHg. While 100g dark chocolate seems like a high intake, this daily ‘dose’ was estimated to reduce the risk of a heart attack or stroke by 21%.
Following the publication of trials with conflicting results, researchers assessed the effects of eating dark chocolate on blood pressure in 15 separate studies.
Nine of these trials compared dark chocolate (50% to 70% cocoa solids) against white chocolate or other cocoa-free controls, while six trials compared high-flavanol cocoa with low-flavanol cocoa over periods of from 2 to 18 weeks. Daily flavanol dosages ranged from 30 mg to 1000 mg in the active treatment groups.
The overall results confirmed a significant blood pressure-lowering effect of both drinking cocoa (cacao) and eating dark chocolate which, overall, reduced blood pressure by an average of 3.2/1.3 mmHg compared with controls.
When they only looked at people with a diagnosis of hypertension or prehypertension, however, the reductions in blood pressure were even greater at 5.0/2.7 mmHg.
The most recent analysis, a 2017 gold-standard Cochrane Review, looked at 35 different trials and again confirmed that the main benefits of dark chocolate and high flavanol cocoa are seen in people with hypertension, in whom blood pressure was significantly reduced by an average of 4.0/1.98 mmHg.
Given that hypertension treatment guidelines strongly recommend integrating lifestyle modifications and complementary treatment with the use of blood pressure medication, eating dark chocolate or drinking high flavonol cocoa is definitely allowed.
Dark chocolate polyphenols
The reason dark chocolate and cocoa powder get the ‘thumbs-up’ when it comes to blood pressure is because the contain large quantities of antioxidant polyphenols – chemicals that help to neutralise some of the harmful chemical reactions occurring as part of our metabolism, and during exposure to pollutants.
The antioxidant polyphenols in dark chocolate and cocoa are mostly in the form of flavanols (also known as catechins, which are also found in green tea).
While some flavanols consist of just one unit, and are classed as monomers, the most protective types contain two, three or more units and are known as oligomers. Dark chocolate is so rich in these polyphenols that its antioxidant score is higher than just about any other food at an extraordinary 103,971 ORAC units per 100g.
Flavanols in cocoa and dark chocolate
Class of flavanol
Number of units
Concentration (mg per 100g cocoa solids)
|Monomers||01 mers||385 mg/100 g|
|02 mers||254 mg/100 g|
|03 mers||271 mg/100 g|
|04 mers||176 mg/100 g|
|05 mers||504 mg/100 g|
|06 mers||317 mg/100 g|
|07-10 mers||162 mg/100 g|
|Polymers||>10 mers||420 mg/100 g FW|
These dark chocolate flavanols have beneficial effects on blood vessel linings to reduce arterial stiffness and improve blood vessel dilation. The main way in which they work involves nitric oxide – a cell signalling molecule – similar to beetroot, l-arginine and sildenafil (Viagra).
Drink more cocoa
The Guna people, who live on islands off the coast of Panama, do not develop high blood pressure with increasing age, and this is largely attributed to the large amounts of cocoa they consume every day. Once they migrate to Panama City and no long follow the same cocoa-enriched diet, this protection is lost.
While most cocoa powders provide around 500mg flavanols per 100g, Aduna Super-Cacao, made from selected, single-origin beans from Ghana, provides eight times more – an extraordinary 4000mg flavanol polyphenols per 100g.
This Super-Cacao has even gained an approved EU health claim that its cocoa flavanols ‘help maintain the elasticity of blood vessels, which contributes to normal blood flow’. To obtain the benefits seen in clinical trials, you need a ‘dose’ of 200mg cocoa flavanols which you can obtain from just 2 teaspoons (5 grams) of Aduna Super-Cacao.
Your blood pressure medicine can taste good!
Dark chocolate also:
- contains monounsaturated fats which raise ‘good’ HDL-cholesterol while lowering ‘bad’ LDL-cholesterol by up to 10%
- protects circulating LDL-cholesterol from oxidation so it is less likely to contribute to hardening and furring up of the arteries
- reduces unwanted platelet clumping to protect against unwanted blood clots
- increases insulin sensitivity and may reduce the risk of developing type 2 diabetes.
Researchers have discovered that eating 45g dark chocolate per day can significantly increase blood flow through the coronary arteries.
Dark chocolate also contains a low level of caffeine, which can improve exercise endurance, increase alertness and decrease the perception of effort and fatigue, and boost fat metabolism without interfering with sleep. Even though dark chocolate does contain a high calorie count, it is not associated with weight gain – if anything, the opposite effect occurs.
Dark chocolate and weight loss
A 14 year study concluded that high dietary intakes of catechins (from chocolate, fruit, vegetables, and tea) was associated with a lower body mass index (BMI) in adult women, which first gave rise to the idea that chocolate polyphenols might have long-term benefits for weight maintenance.
In a study involving around a thousand healthy adults, those who ate the most chocolate had a greater intake of calories over all, yet had a lower Body Mass Index at all ages and for both men and women. The level of exercise taken did not change these results.
Similar results were found in a group of 1458 teenagers, whose diets were analysed, their height and weight measured, waist circumference recorded, and fat stores assessed using skinfold measurements and bioelectrical impedance analysis. A higher chocolate consumption was associated with lower levels of total and central fat, BMI, and waist circumference, regardless of other factors such as age, stage of puberty, total energy intake, amount of fruit, vegetables, tea or coffee consumed, or level of exercise.
Researchers now believe that dark chocolate promotes weight loss in a number of ways, including effects on mood, stimulating fat burning, and by lowering blood levels of ghrelin – an appetite-stimulating hormone produced in the stomach and pancreas.
The relationship between appetite and levels of intestinal hormones was assessed in 12 women who were asked to smell chocolate and let it melt in their mouth before swallowing. Using 30g dark chocolate containing 85% cocoa solids per dose, researchers founds that both eating chocolate and smelling dark chocolate suppressed appetite to a similar degree. Blood hormone levels suggested that smelling chocolate stimulates olfactory sensors that, in turn, suppress the secretion of ghrelin – an intestinal hormone that stimulates appetite.
Dark chocolate also reduces weight gain through effects on insulin sensitivity, and possibly by neutralising the effects of the stress hormone, cortisol.
So if fancy a few squares, feel free. Just make sure your chocolate is at least 70% cocoa solids to obtain the benefits.
If your blood pressure is raised, self-monitoring is key to maintaining good control.
Click here for advice on choosing a blood pressure monitor to use at home.
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