ON THIS PAGE
- What is dark chocolate?
- What makes dark chocolate healthy?
- Health benefits of dark chocolate
- Cardiovascular disease and stroke
- Insulin resistance and type 2 diabetes
- Immunity and cancer
- Central nervous system
- Skin health
- Detoxification of heavy metals
- Effects on body weight
- Psychoactive effects
- Sexual health
- Nutritional value
- When is chocolate bad for you?
- Negative health effects of eating dark chocolate
What is dark chocolate?
Dark chocolate is a solid product made of roasted cocoa bean mass, with or without the addition of extra cocoa butter and with or without some form of sweetener (whether sugar or artificially based).
These are the bases that define dark chocolate. However, additional labelling laws can be applied, for instance:
In the U.S., the law states that the dark chocolate (semisweet/bittersweet) contents must be chocolate liquor >= 35% and milk solids < 12%.
There are two different components in cocoa:
- Non-fat cocoa solids
These contain high antioxidant activity and are rich in polyphenols, and some minerals. It is also one of the highest in fiber foods. Most health benefits of dark chocolate are derived from these elements.
- Cocoa butter
It contains a high amount of fatty acids and relatively (in comparison to non-fat cocoa solids) small amounts of antioxidants. Cocoa butter has a neutral effect on health.
A few facts about chocolate products:
- Cocoa and cacao means the same, although recently “cacao” has been popular within raw vegan circles to describe an unroasted cocoa/cacao products.
- Some show the “Cocoa %” or “Cocoa solids %” on their labels, as in the image below. This percentage indicates how much of the total non-fat cocoa solids and cocoa butter is contained in the chocolate. However, the specific proportions of the non-fat and the fat components are not disclosed to consumers, since they are considered to be a part of the secret recipe.
- Generally, the higher the cocoa percentage is, the more bitter, harder and less palatable the chocolate tastes. The bitter taste comes from the health promoting flavonols.
- Extra cocoa butter is usually added to dark chocolate to make it smoother and less bitter.
What makes dark chocolate healthy?
- The higher the non-fat cocoa solids component of the “cocoa %”, the healthier the product. (1)
- “Cocoa%” is a good but not completely reliable indicator of the polyphenol contents of dark chocolate. For instance, some chocolates of 85% cocoa may have less polyphenols than 70% cocoa chocolates (see below).
- Roasting cocoa beans can reduce the antioxidant activity of flavonoids by more than 10 times in comparison to natural cocoa, and this reduction increases with the roasting time. (2, 3).
- Roasting cocoa beans also increases the content of melanoidins. These are a type of Maillard reaction product that are formed during the roasting process, which partially replace other antioxidants (4)
- Alkalizing (Dutching) of cocoa is used to neutralize the acidity of the chocolate and the bitter taste of flavonoids. This significantly reduces the flavonol content in cocoa.Heavily alkalized chocolate can have up to 5 times less flavonols than natural cocoa (although those amounts are still higher than low cocoa chocolate, e.g. milk chocolate) (5, 6)
- Increasing the amount of sugar and other non-cocoa ingredients, decreases the health properties of dark chocolate (1)
- The plant’s genetic characteristics and where it was grown, influence the polyphenol and toxic metal composition of the final product. (1)
- The healthiest chocolate is organic, not alkalized, minimally processed with the highest contents of non-fat cocoa solids and the least amount of sugar and other additives.
Dark chocolate – health benefits
The properties of the cocoa’s components may have a significant impact in the prevention of certain medical conditions and decreasing their risk factors.
Some sources consider dark chocolate as a medicinal food.
However, more studies are needed to determine whether eating chocolate has similar health benefits to its individual components.
It also needs to be established the dosages and frequencies of chocolate consumption required to exert a significant effect on health.
For instance, an extract of theobromine reduces coughs in cases of acute bronchitis, but eating dark chocolate may not necessarily have the same effect, even though it is very rich in theobromine.
The following is a list of dark chocolate benefits:
Dark chocolate benefits related to cardiovascular disease and stroke
Eating dark chocolate is usually associated with a lower risk of cardiovascular disease and stroke.
Dark chocolate consumption is linked with the reduction of inflammation, hypertension and vasodilation, the relaxation of arteries, the inhibition of platelet activation, aggregation and adhesion, the increase of HDL cholesterol and the reduction of lipid oxidation.
Flavonols that are present in cocoa significantly reduce various risk factors of cardiovascular disease.
- Eating dark chocolate reduces the risk of cardiovascular disease and stroke thanks to high contents of flavonols.
Dark chocolate benefits related to insulin resistance and type 2 diabetes
In addition to reducing insulin resistance and improving glucose tolerance, polyphenols may also induce beta cell regeneration and stimulate the secretion of insulin.
All of these effects are known to reduce the risk of type 2 diabetes.
Nevertheless, please note that consuming dark chocolate on a regular basis for extended periods of time is more effective than eating it sporadically.
A 50g serving of dark chocolate, with cocoa solids of about 50%, and roughly a 50-50% ratio of fat to carbohydrates, has a low GI=23 and only a GL of 6. (9)
Despite the current unavailability of lab data (only some estimates (10) regarding GI and GL levels on higher cocoa percentages of chocolate, we can safely assume that since 50-50 cocoa to sugar ratio has low GI and GL, that chocolates with at least 70% cocoa, have even smaller GI and GL.
Therefore, the higher the percentage of cocoa chocolate, the safer it is for diabetics.
A recent (2017) meta analysis of prospective studies has shown that chocolate has protective effects in type 2 diabetes. The optimal dose has been shown to be 30g serving of chocolate twice per week. No benefit was observed when consumption was increased above 6 servings per week. (11)
- Dark chocolate has been shown to be safe for diabetics.
- Eat 30g of chocolate 2-6 times per week for optimal protective effects in type 2 diabetes.
Dark chocolate benefits related to immunity and cancer
Although there are no studies of the cocoa effects on the immune system in humans, there are some preliminary studies performed on rats and in-vitro.
The cocoa’s powerful antioxidant properties and its ability to enhance apoptosis of cancer cells (14) may also have a key role in reducing the risk of cancer.
NOTE: there are no studies on the effects of cocoa consumption on cancer in humans.
- Dark chocolate may be beneficial in improving immunity and cancer prevention. However, current evidence is weak.
Dark chocolate benefits related to central nervous system
Preliminary studies show that epicatechin has a relevant role in the formation of long-term memory. (15) These studies also indicate that cocoa’s flavonoids improve cerebral blood flow (16) and may be protective against neurodegeneration, and neuroinflammation, which are linked to neurological conditions, such as Parkinsons, Alzheimers and stroke.
NOTE: there are no clinical trials on the effects of cocoa consumption on neuroprotective properties on humans
- Preliminary studies show that flavonoids in dark chocolate may be neuroprotective and beneficial in improving brain function. Evidence is weak, however, and clinical trials are needed.
Dark chocolate benefits related to skin health
Cocoa topical application is known to be effective, but specific studies on the effects of the consumption of dark chocolate on the skin are (17)
The consumption of chocolate high in flavonols (Epicatechin – 61 mg/day and catechin – 20 mg/day) has been shown to decrease the UV light induced erythema (redness of the skin) by 25%. However, the chocolate used in this study is not commercially available. (18)
Nevertheless, flavonols may have skin protective properties, because they cause an increase of blood flow to the skin, delivering oxygen, micro nutrients and improving thermoregulation. (19)
NOTE: more studies on humans are needed to prove that dark chocolate consumption can be effective in skin health.
- Eating dark chocolate and high in cocoa powder chocolate products has been shown to be protective for the skin.
Dark chocolate benefits related to detoxifying effects
Cocoa in dark chocolate contains compounds soluble in water and simulated gastrointestinal conditions and polypeptide and polysaccharide complexes.
These compounds bind to cadmium and lead, forming complexes that are resistant to gastrointestinal conditions. As a result, a significant proportion of these metals is excreted. Such properties indicate a possible detoxifying effect of cocoa. More studies are needed. (20)
- Cocoa in dark chocolate contains compounds that have detoxifying effects. More studies are needed.
Dark chocolate benefits related to body weight
On the one hand, dark chocolate is a high caloric food and can be indulgent. On the other hand, its constituents alter the metabolism of fat and sugar in the body.
The plausible reason for the lack of weight gain is due to the improvement of insulin sensitivity, lipid metabolism and uptake of glucose.
Eating dark chocolate may also reduce appetite and increase satiety. (23)
Overall, findings show that weight gain is at most negligible with a moderate consumption of dark chocolate and its health benefits override that risk, even in obese individuals. (24)
- Moderate consumption of dark chocolate is associated with at most negligible weight gain.
- Health benefits of dark chocolate such as improvement of insulin sensitivity, lipid metabolism and uptake of glucose override that risk even in obese individuals.
Dark chocolate benefits related to psychoactive effects
Chocolate may be associated with a better cognitive function, due to its high flavanol and methylxanthine contents, but more studies are needed. (25)
- Dark chocolate may be beneficial in improvement of cognitive function, and has shown to be effective short-term mood enhancer.
Dark chocolate benefits related to sexual health
Despite a popular belief, there is no scientific evidence that cocoa or chocolate consumption have an aphrodisiac effect and increase sexual desire or pleasure in women. (29)
Low NO production is associated with not only hypertension, but erectile dysfunction. Although high cocoa dark chocolate consumption increases vascular nitric oxide (NO) production, improving vascular blood flow and reducing blood pressure, more studies are needed that show that eating dark chocolate improves men’s sexual function. (30, 31)
- Dark chocolate benefits as an aphrodisiac have not been proven.
- High cocoa dark chocolate may be helpful in men’s sexual dysfunction. More studies are needed.
Nutritional value of dark chocolate
In addition to the high amount of polyphenols and theobromine, chocolate is a very nutritious food. As mentioned before, it contains plenty of fiber, and is a great source of minerals, such as copper, magnesium, iron, zinc, manganese and phosphorus.
Its fatty component is rich in oleic acid – monounsaturated fatty acid (also a component of olive oil).
- Dark chocolate is a great source of copper, magnesium, iron, zinc, manganese and phosphorus.
When is chocolate bad for you?
Chocolate is not for everybody. Eating it may have some negative health effects on some sensitive people. However the evidence varies across sources and is often inconclusive.
Chocolate has shown to lower the esophageal sphincter pressure (loosening the muscle between esophagus and stomach) and exacerbate heartburn symptoms or gastroesophageal reflux disease (GERD).
There are some reports of chocolate causing migraines in sensitive people. Phenylethylamine is one of the possible suspects for this effect. However, the evidence is weak. (34)
A double-blind study, for instance, has found that chocolate does not play a significant role as a cause of headaches. (35)
- Weight gain
Dark chocolate is high in calories and may cause concern, if consumed as part of an unhealthy diet. However, a potential weight gain is not due to the cocoa components but rather due to its high caloric value and high sugar contents, together with an overall unhealthy diet. (24)
Chocolate has been reported to cause acne, but this claim is not supported by scientific studies. The reports may be associated with other ingredients of chocolate products rather than the cocoa component, such as sugar or milk. (36)
Chocolate consumption may cause constipation in some people. (37)
- Toxic metalsCocoa shells can contain significant amounts of toxic bismuth and arsenic. Therefore, although cocoa shells may be loaded with healthy polyphenols, chocolates with blended shells may be harmful overall. (38)
Furthermore, cocoa has some trace amounts of cadmium and lead. If taken in large amounts, these metals may be toxic. However, in cocoa, a proportion of these metals bind to insoluble substances and are excreted. (20, 39, 40)
Although some chocolates have been shown to contain amounts of cadmium that are higher than recommended by WHO, in adults the bioavailability of toxic metals in cocoa is very low.
Please be aware that there are warnings that excessive amounts of dark chocolate may be unsafe for children due to these heavy metals. A 10g piece of dark chocolate may contain as much as 20% of the daily lead oral limit. (38)
- Some sensitive people may experience worsening of reflux symptoms, migraine or acne after eating chocolate.
- Eating too much dark chocolate may result in constipation.
- Toxic metal in dark chocolate may affect children who eat dark chocolate in excess.