Chocolate is the most famous derivative product of cacao. What's your personal take on chocolate?
- A boatload of calories?
- A comfort food for those Bridget Jones days?
- A decadent sensual indulgence?
- Or just maybe it is 'natures medicine' and a justifiable superfood?
There is growing interest in the therapeutic benefits of chocolate. Listed among the supposed benefits of chocolate are improved mood, heart health, lower BP, cancer prevention, and aphrodisiac properties - not to mention the taste, smell and texture of great chocolate.
Can we find scientific justification for our cacao fests?
What Is Cacao?
Cacao is a complex food containing many bioactives. It comes from the evergreen Theobroma tree which is native to South America.
The term cacao comes from the Mayan language where it was referred to as 'ka-kaw'.
Theobroma translates into 'Theo' or God and 'broma' drink -which when put together gives us 'drink of the gods'. This was the term coined for the tree by the Swedish naturalist Carl Linnaeus way back in the 1750s. (We heartily agree with you Carl).
Food and beverages from the Theobroma cacao tree have been enjoyed by humankind since 460AD. It was also used in the indigenous tribes of MesoAmerica for three main medicinal purposes:
- as an energy dense food to treat emaciation
- to stimulate the nervous system and
- to improve bowel transit times.
It was brought to Europe by Christopher Columbus and arrived in Spain at the end of the sixteenth century. Casanova allegedly got his mojo from chocolate.
Just to clarify the nomenclature:
- cacao refers to the seed of the Theobroma cacao tree in its natural or unprocessed form
- the term cocoa is used when the cacao beans have been processed (an important vowel reversal as we will see)
- cocoa nibs are the cotyledons that remain after winnowing of cocoa beans (removal of the outer shell)
- cacao can be separated into cocoa butter and non-fat solids (cocoa powder)
- liquor refers to a paste made from ground, roasted, shelled and fermented beans and contains cocoa butter and non-fat solids
- chocolate is a combination of cocoa liquor, cocoa butter, sugar and flavorings.
- Cocoa butter contains iron while the non-fat solids contain vitamins, fibre and polyphenols.
- The percentage of cocoa in the final product determines the color of the chocolate.
There are three main types of chocolate based on color:
- dark chocolate: more than 35% by weight of cocoa liquor
- milk chocolate: 10-12% by weight of cocoa liquor plus condensed or powdered milk
- white chocolate: more than 20% cocoa butter (and no solids) by weight plus sweeteners and other ingredients.
The cacao industry is very important economically. The main producer of cacao worldwide is the Cote d'Ivoire which produces 1.2 million tons of cacao per year. This is followed by Indonesia and Sri Lanka.
Chocolate consumption varies worldwide with the lowest rates in China at 0.12kg per person per year. Average chocolate consumption in the USA is 5.18kg per person per year. The winner is my home country of Ireland which weighs in at an average chocolate consumption of 11.85 kg per person per year. I think that I might know many of those stalwart Irish patriots who keep Ireland at the top of the chocolate (or seacláid as we call it) leaderboard.
Cacao is a rich source of:
- methylxanthines (caffeine, theobromine)
- flavanols (catechins, eipcatechins, procyanidins)
It is thought that humans perpetuated habits that either gave them pleasure or a survival advantage. That makes good sense to me. It is thought that cacao offered both these benefits to early mankind in that:
- chocolate tasted good and
- had psychoactive properties that helped man think more clearly or hunt more strategically.
Let's take a closer look at the bioactive ingredients and nutrients in chocolate.
Chocolate contains a mixture of monounsaturated fatty acids (oleic acid) and saturated fatty acids (palmitic and stearic acid). Although the lipid content of chocolate is relatively high, approximately one third of the lipid in cocoa is stearic acid which is a neutral lipid from the perspective of plasma lipids and atherosclerosis. Go chocolate.
The bran of the cocoa bean is high in fibre but much of the bran is lost in the processing. The fibre content of 100kcal of dark chocolate is 1.7gms as compared to an equivalent amount of milk chocolate which contains only 0.6gms.
Cacao contains theobromine (26,000 mg /kg), caffeine (2,400 mg/kg) and theophylline (not determined). This compares to dark chocolate which contains theobromine (5000mg/kg), caffeine (625mg/kg) and theophylline (not determined).
Chocolate contains more phenolic antioxidants than most other food sources. The flavanol content of dark chocolate is five times that of milk chocolate. Flavanols have an astringent bitter taste which is often masked by sugar and other flavourings. There is ongoing research into microencapsuation of cacao to mask the astringent taste and allow a higher intake of cacao flavanols.
The tricyclic structure of flavonoids determine the antioxidant effects including scavenging of reactive oxygen species, chelation of iron and copper and upregulation of antioxidant defences.
The flavanol content of cocoa liquor is 1400mg per 100gms, while dark chocolate has 170mg per 100 gms. Red wine only has 22mg of flavanol per 100gms. Does it have to be an either or situation? May I perhaps suggest some red wine with cocoa or dark chocolate and have no loser here?
Magnesium: dark chocolate (70-85% cacao) contains 36 mg of magnesium per 100kcal which represents 9% of the recommended daily allowance. Magnesium is an important co-factor in protein synthesis, muscle relaxation, blood pressure control and anti-arrhythmics.
Copper: milk chocolate provides 10% of the recommended daily allowance of copper per 100kcal serving. As you would need to ingest 1000 kcal of milk chocolate to reach the recommended daily allowance, it is unlikely that milk chocolate consumption would produce copper toxicity (unless maybe you live in Ireland). Dark chocolate provides 31% of the recommended daily allowance of copper.
Potassium: Chocolate is relatively low in potassium. Dark chocolate contains 114mg of potassium per 100kcal which is only 2% of the recommended daily allowance.
Iron: Milk chocolate contains 0.42mg of iron per 100kcal which is 5% of the recommend daily allowance. Dark chocolate contains 1.90mg of iron per 100kcal which provides 25% of the recommended daily allowance.
Not all chocolate products are created equally. This can be due to differences in the soil characteristics where the cocoa beans grow, in the manufacturing processes and differences in the milk powders used.
A 2009 study looked at top selling cocoa products in 6 categories (natural cocoa powder, unsweetened baking powder, dark chocolate, semisweet baking chips, milk chocolate and chocolate syrup) (1)
There was an over ten fold variation in procyanidin content across the products.
A big plus for cacao is stability of bio-actives. The antioxidant activity of green tea degrades over time but not so for cacao products. Milk chocolate bars maintain their antioxidant activity for 50 weeks while cacao powder and beans retain their anti-oxidant activity for over 75 years.
Chocolate accounts for 49% of all food cravings (especially in women and peri-menstrually). Interestingly, most chocolate cravings are for milk chocolate which has a lower content of bioactives which suggests that chocolate cravings have more to do with taste and texture than bioactive content.
Is There Any Research?
There are 3282 publication relating to cacao which includes 296 clinical trials. Let's compare that to another modern day "super food" avocado which has over 1246 publications and 33 clinical trials.
Does It Prevent Anemia?
There are no specific studies looking at cocoa for anemia.
We know that cocoa contains iron. A study in mice compared the absorption of iron from ferrous sulphate, ferrous citrate and cocoa and found that cocoa compared favorably in terms of iron absorption to ferrous citrate but was less than than of ferrous sulphate (2).
The recommended daily intake of iron is 8mg in men and 18 mg in women. Recommended intakes in vegetarians and pregnant women are substantially higher. Considering the fact that milk chocolate provides 0.42mg of iron per 100kcal and dark chocolate contains 1.90mg of iron per 100kcal, both contribute somewhat to iron stores but only dark chocolate makes any meaningful iron contribution in adults who are non-pregnant or non-vegetarian.
Dark chocolate contributes to iron stores and thus prevention of anaemia in non-pregnant, non vegetarians.
Does It Reduce Risk of Cardiometabolic Disease?
Epidemiological studies suggest that cacao rich products reduce the risk of cardiovascular disease.
The Kuna Indians of the San Blas islands of Panama consume 30 ounces of a cocoa beverage per day (equivalent to 1880 mg of procyanidins) and enjoy exceptionally low rates of hypertension, myocardial infarction and cancer compared to other Panamanians (3)
Flavanols increase the production of nitric oxide in the endothelium which results in vasodilation and could lower BP. Additionally, they antagonise digestive enzymes and glucose transport and influence insulin signalling which can impact on glucose metabolism.
Australian investigators carried out a full Cochrane review looking at the effects of cacao on BP (4). This review is up to date as it was only published last year.
A total of 40 trials involving 1804 study participants were analayzed. Overall, cacao showed a small but statistically significant effect on lowering BP. To look at this in more detail, people with baseline hypertension enjoyed a 4mmHg decrease in systolic BP. No effect was noted in patients who were normotensive at baseline. Sub-group analysis suggested a trend towards a greater reduction in unblinded trials compared to double-blinded trials and this could not be explained by any other co-factor. Cacao products were well tolerated (what a surprise). Only 1% of study participants complained of symptoms of nausea and gastrointestinal upset.
A collaboration between Brown University and Harvard University carried out a meta-analysis of randomized controlled trials evaluating the effects of cacao on cardiometabolic biomarkers (5)
A total of 19 trials comprising of 1131 participants were included in the analysis. Significant improvements between cacao and placebo were noted for major clinical risk factors of cardiometabolic disease:
- HDL cholesterol
- fasting insulin
- CRP and
- vascular cell adhesion molecules.
A meta-analysis of 66 studies assessed the impact of cocoa on inflammatory biomarkers (6). Cacao consumption reduced inflammation possibly by lowering the activity of monocytes and neutrophils and was more noticeable in patients with baseline inflammatory dysregulation as opposed to healthy controls.
Cacao has been shown to have favorable effects on a range of cardiometabolic markers. Logically, care has to be taken not to offset these benefits by consuming excessive quantities of highly processed sugar laden chocolates.
Does It Enhance Mood?
In an attempt to mimic white, milk and dark chocolate, volunteers took either:
- white chocolate containing no methylxanthines
- white chocolate containing low levels of methylxanthines (8mg of caffeine plus 100mg of theobromine) or
- white chocolate containing high levels of methylxanthines (20mg of caffeine plus 250mg of theobromine) (7)
Study subjects conducted a test battery consisting of a long duration simple reaction time task, a rapid visual information processing task, and a mood questionnaire before and after ingestion of the different formulations of white chocolate. (My kind of research- sign me up).The study found that the psychostimulant effect of cholocate was due to the methylxanthine component.
Spanish investigators analysed data from a cohort of 4599 people and found that regular consumption of chocolate did not affect physical or mental components of a health related quality of life score (8). Interestingly, 72% of the cohort did not consume chocolate at baseline suggesting that this cohort may not be fully representative of the general population (definitely not an Irish study).
A systematic review published in 2013 considered the findings of 8 studies and found that 5 showed evidence of improvement in mood or attenuation of low mood and 3 showed clear evidence of cognitive enhancement after cocoa. Of the studies, reviewed, two showed no behavioural benefits but did show alterations in brain activation patterns (9)
A randomized controlled trial in 30 adults investigated the effects of cocoa flavanols on mood and cognitive performance during sustained mental effort (10).
Study participants consumed drinks containing 520mg, 994 mg or placebo with three day washouts between drinks. They completed a series of cognitive function tests while on each arm of the study. Consumption of the cocoa drinks improved performance in the acute cognitive function tests. The authors hypothezise that cocoa exerted this effect on acute cognitive performance due to favorable changes in endothelial function and blood flow.
My all time favorite of the studies looked at the effects of 'intentionally enhanced' chocolate on mood (11). In this study, participants were given half an ounce of dark chocolate twice daily for a week. Some of the participants received chocolate that had been intentionally treated to increase a sense of vigor, energy and well-being and the rest of the chocolate was just good old dark chocolate
Overall mood improved significantly more in the 'intentionally treated' chocolate than in the control chocolate (P = .04) and specifically improvements were noted for reduced fatigue and increased visor. Did you even see the movie Chocolat where the lead character used to alchemically blend special chocolate formulations to help people fall in love etc? I wonder if the authors of this study were inspired by that movie?
The results on studies of chocolate as a mood enhancer suggest that chocolate may improve mood and overall brain function.
Does It Relieve Constipation or Help Diarrhea?
A study in twenty-two healthy human volunteers compared either a high-cocoa flavanol (494 mg cocoa flavanols/day) or a low-cocoa flavanol (23 mg cocoa flavanols/day) for 4 weeks. Following a 4-week washout period, the study participants switched over to opposite arm of the study. Fecal samples were recovered before and after each intervention, and bacterial numbers were measured by fluorescence in situ hybridization techniques.
The daily high cocoa flavanol drink significantly increased the bifidobacterial (P < 0.01) and lactobacilli (P < 0.001) populations but significantly decreased clostridia counts (P < 0.001) which is considered advantageous for the gut microbiome.
Cacao contains fibre but this is largely removed in the manufacturing processing which limits the potential of cacao as a constipation aid. Cacao also contains magnesium and as such could potentially act as a pro-motility aid.
A study in 56 chronically constipated children showed that children who received cocoa husk had a non-significant increase in the number of bowel movements and less hard stools as compared to control children (13).
Cacao has also been used traditionally for the treatment of diarrhoea.
Researchers from the Children's Hospital Oakland, California tested different doses of flavonoids in cocoa in a cell culture of colonic epithelial cells (14). The study found that cocoa derivatives (epicatechin > catechin > procyanidin) act as mild inhibitors of c-AMP (cyclic AMP) stimulated secretion in the intestine.This makes chocolate a possible anti-diarrheal candidate but is unproven as of now in humans.
Cacao may help the microbiome and unprocessed cacao may help with constipation but there is no evidence to support store purchased chocolate bars for constipation. There are no human clinical studies looking at chocolate for diarrhea.
Other Possible Uses
Interrogation of data from the National Health and Nutrition Examination Survey (NHANES), 2007-2008 showed that theobromine is directly related to sleep duration (15).
There are no studies looking at the effects of chocolate on sleep but there is an Italian study in 32 healthy volunteers which showed that flavanol-rich chocolate counteracted vascular impairment after sleep deprivation and restored working memory performance (16). Maybe that's why doctors live on chocolate?
Improvement in cognitive performance could be because of the effects of cocoa flavonoids on blood pressure and peripheral and central blood flow.
A 24 week trial of moderately photo-aged Korean women with visible wrinkles (aged 43-86) randomized women to a placebo or cacao containing beverage (17). There was a statistically significant improvement in the cacao group in terms of average roughness, wrinkles and elasticity but no improvement in hydration.
A group of human volunteers ingested cocoa for 3 weeks before and after influenza vaccination and immune parameters were compared to participants who did not take cocao (18). No difference was noted in neutralising antibodies between the groups but natural killer cell activity did increase in the cacao arm of the study.
It would be remiss not to mention migraine. Chocolate is typically quoted as a trigger for migraine. A 2014 study showed that the risk of chocolate induced migraine was 2 to 3 fold lower than factors such as stress, fasting, lack of sleep or alcohol (19).
Is Eating Cacao Safe?
Cacao is an energy dense food source and care needs to be taken not to gain weight while trying to incorporate the health benefits of chocolate into your culinary medicine cabinet.
Side effects of cacao include acne, migraine (though this is disputed as described above) and heart burn (as it relaxes the lower oesophageal sphnicter).
Cocao is a rich source of oxalate and cases of renal stones have been described with excessive intake of cocoa. One study looked at acute dosing of cocoa in children and found that it increased excretion of oxalate and calcium in the urine which supports the link between cocoa and renal stones (20).
Cacao allergy has been described. Like any food product, chocolate can be contaminated by faulty manufacturing processes. An outbreak of Salmonella infection from a Norwegian supplier of chocolate was reported in 349 cases in Norway and 12 in Finland (21).
Chocolate as medicine? There is certainly evidence to support some health benefits of cacao and chocolate. However, to put things in perspective, food pyramids usually include small amounts of high quality dark chocolate at the very top of the food pyramid. The health benefits are seen with high quality dark chocolate (where the ingredients list cacao ahead of sugar or any other ingredient). If I were to be totally honest, this is not the type of chocolate consumed by the medical community or the general Irish population. Small amounts of dark chocolate ('seacláid dorcha') and not milk chocolate ('seacláide bainne') or white chocolate ('seacláid bhán') would be healthy and smart.