The Science of Chocolate

A chocolate a day is good for your heart

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“The secret elixir of life may have less to do with wheat germ and more with cocoa” – Boston Globe

“Sacred medicine you are being counseled.
It’s like the cocoa counsel.
In the beginning one day sacred gold transformed to his liking your live being.
Sacred medicines you are being counseled.”
– Stories, myths, chants, and songs of the Kuna Indians By Joel Sherzer, Teresa Lozano Long Institute of Latin American Studies

“There is a kind of alchemy in the transformation of base chocolate into this wise fool’s-gold, a layman’s magic that even my mother might have relished… The mingled scents of chocolate, vanilla, heated copper, and cinnamon are intoxicating, powerfully suggestive; the raw and earthy tang of the Americas, the hot and resinous perfume of the rain forest. This is how I travel now, as the Aztecs did in their sacred rituals… The Food of the Gods, bubbling and frothing in ceremonial goblets. The bitter elixir of life.” – Chocolat

Watching a ‘feel-good’ romantic film over a tub of chocolate ice-cream … that is my idea of preserving my heart and mind (and soul) with a regular dose of chocolate, ‘just what the doctor ordered’ after a long and stressful week. I admit I have something of a ‘sweet tooth’, and I remember thinking, “If only chocolate were good for you… I’d be set.” But that piece of DOVE dark chocolate I have so often enjoyed with my morning cup of coffee (It’s not my fault my favorite coffee-house keeps their exquisite singly packaged DOVE chocolate squares by the cash register) may be serving my heart’s health, not just my emotional cravings. You may have heard lately about the health benefits of chocolate, in the news and online. My mother used these reported benefits to shove an entirely too large piece of chocolate pie down my throat at Christmas time. “A woman should have curves.” But are these reports simply rumors, a ploy by candy-companies to boost M&M and chocolate bar sales to the more health-conscious members of society? To the pleasure of chocolate lovers, the news stories on the medicinal attributes of daily doses of cocoa run much deeper than a marking agenda… back to investigative studies performed by scientists at prestigious research universities. Chocolate Tourism in Belize:

How are chocolate and cocoa, ground from the cocoa bean, good for the heart? According to research studies, chocolate in the diet is shown to decrease blood pressure, both diastolic (when the heart is relaxed) and systolic (when the heart is contracting) pressures (Hooper 2008). Maintaining low blood pressure is an important factor in decreasing an individual’s chance of developing cardiovascular disease and heart attacks. Intake of cocoa has also been correlated with decreases in oxidative stress, increased bioavailability of nitric oxide (NO), increased blood flow according to imaging studies in the brain (Fisher 2006), improved skin structure and function (Heinrich 2006), preservation of brain function (Reznichenko 2005), improved spatial memory (Praag 2007), and protection against unwanted cellular death. Oxidative stress involves damage caused by reactive oxygen species, and is implicated in diseases as diverse as atherosclerosis, Alzheimer’s, cancer, and aging in general. Decreased NO concentration in the blood is correlated with high blood pressure and other cardiovascular risks. In other words, increased production of nitric oxide, often observed in individuals consuming flavanol-rich diets, can lead to decreased risk of cardiovascular disease, due to the reduction of endothelial dysfunction (dysfunction of cells lining blood vessels), platelet aggregation, and inflammation (Cooper 2008). A 2008 population study, originally aimed at discovering a genetic basis of abnormally low blood pressure rises with age among Kuna Indians, or finding genes that might protect against hypertension, found that the San Blas island-dwelling Kuna drank cocoa as their major drink, consuming up to 35 cups per week. This cocoa is rich in raw beneficial compounds due to a minimal amount of the processing that takes place in the production of commercial cocoa powders and chocolates. Taking into account salt intake and other dietary factors of the island Kuna, like consumption of raw fruits, vegetables, and fish (rich in Omega-3 fatty acids), researchers found that the rare cases of hypertension and cardiac disease among the population was most likely attributed to their high intake of cocoa. Cocoa in the form consumed by the Indians was found to improve vascular function (i.e. improve heart health) in the elderly (70-80 years of age) and patients with type II diabetes. (Hellenberg 2006) Hellenberg 2006.jpg

The health benefits of cocoa are attributed to flavanols, a type of phytochemical, i.e. a type of chemical that occurs naturally in plants. According to population studies of health patterns associated with diet, there exists an “inverse correlation between the intake of flavanol-containing foods and coronary artery disease (CAD) mortality.” (Heiss 2010, Arts 2005) In other words, cardiovascular disease may be improved in those individuals who maintain a flavanol-rich diet, along with exercise regimens and other heart-healthy practices. Coronary artery disease, a leading cause of death in the United States, is influenced by many contributing risk factors, but one of the most important (and controllable) is diet. The flavanol compounds, like those found in raw cocoa, have been shown in peer-reviewed research studies to lead to “improvements of vasodilation, blood pressure, … the attenuation of platelet reactivity, and the improvement of immune responses and antioxidant defense systems.” (Schroeter 2006) A 2006 study in PNAS found that a specific flavanol component of cocoa, (-)Epicatechin, mediates the beneficial effects on vascular function via enhancement of endothelium-dependent vasodilation and augmented microcirculation (Schroeter 2006). Vasodilation is a term for the widening of blood vessels, like your veins and arteries, caused by the relaxation of the smooth muscle cells inside the vessel walls. An important compound that signals the smooth muscle cells to relax is nitric oxide (NO). Schroeter et al showed a link between flavanol compounds circulating in the blood after ingestion of flavanol-rich cocoa and increased flow-mediated vasodilation (FMD), as most likely caused by increased nitric oxide bioactivity (Schroeter 2006). (See article figures here – Also as part of the Schroeter et al study, Kuna Indians living on the island of San Blas were shown to have urinary nitrite+nitrate levels at least twice that of Kuna living on the mainland. This difference is attributed to the 3-4 cups (= 600-900 mg of procyanidins) of cocoa per day, vs. the less than 4 cups per week for the mainland inhabitants, which the island dwellers drink. This high intake of flavanol-rich cocoa is hypothesized to be an important reason for the minimal increases in blood pressure with age and rare cases of hypertension and cardiovascular disease observed among the Islanders (Schroeter 2006). cocoa beans.jpg

A 2010 review by Fraga et al demonstrated that cocoa flavanols (like (-)Epicatechin) improve endothelial function and decrease blood pressure (Fraga 2010) not only via the increased production of NO through the activation of the enzyme eNOS – nitric oxide synthase (Ramirez-Sanchez 2010), but also via the antioxidant power of (-)Epicatechin (EC). As a free radical scavenger, a classic antioxidant, EC can scavenge the superoxide anion (O˙-2) which reacts with NO, decreasing the bioavailability of the NO compound as well as leading to oxidative stress. EC also, and perhaps more importantly, has been shown to inhibit (Steffen 2007) an enzyme (NOSNADPH oxidase) which is an important producer of the superoxide anion, thereby also indirectly elevating NO levels in vasculature by lowering levels of superoxide. Another 2010 study by researchers at the Universities of California-San Francisco and California-Davis (Heiss 2010) demonstrated that improvement of endothelial function in patients with coronary artery disease who digested dietary flavanols present in cocoa drinks was associated with mobilization (i.e. increased number and function) of circulating angiogenic cells (CACS). CACS, also known as early endothelial progenitor cells, are rare, bone marrow derived cells that circulate in the blood stream and contribute to the repair of vascular/blood vessel injury by differentiating into endothelial cells (Werner et al.). A high intake of flavanols lead to increased CAC numbers, up to 2x more than the number of these cells present with no intake of the cocoa flavanols. The extent of CAC increase observed with cocoa consumption was competitive with established drug (statins, estrogen) treatments, increases in exercise and smoking cessation (Heiss 2010). “Our data support the concept that dietary flavanols, in addition to improving cardiovascular functions, can facilitate endogenous repair mechanisms that act synergistically with current medical therapy.”(Heiss 2010) balance.jpg

So, should we all rush to fix our Swiss Miss packets of hot cocoa? An important consideration in the consumption of cocoa or chocolate for health reasons is the type of cocoa or chocolate you choose, and the amount of post-harvest handling and commercial processing that go into the product. Many organic cocoa products can be purchased that preserve the natural high levels of flavanols in the cocoa bean by avoiding elevated temperatures or chemical processing (CocoaPro®, Sunfood Organic Cocoa). If you are debating Dark or Milk: Dark chocolate products are typically higher in flavanols that milk chocolate products. Beware of white chocolate… which generally lacks any of the beneficial flavanols contained in the cocoa bean.

Not a big chocolate fan? Other flavanol-rich foods include tea, wine, and many fruits and vegetables. The specific flavanol (-)Epicatechin which has been associated with the beneficial effects of cocoa is also found in grapes, blueberries, tea, and wine. “In general, diets rich in plant foods are associated with a reduced risk for vascular disease.” (Hung 2004) A List of Phytochemicals found in various foods can be found online. More research articles on the health benefits of cocoa can be found at

1. Arts IC, Hollman PC. Polyphenols and disease risk in epidemiologic studies. Am J Clin Nutr 2005; 81 Suppl: 317-25
2. Cooper et al. Coca and health: a decade of research. Britich J. Nutr. 2008; 99:1-11
3. Fisher et al. Cocoa flavanols and brain perfusion. J Cardiovasc Pharmacol 2006; 47:S210-S214
4. Fraga et al. Cocoa flavanols: effects on vascular nitric oxide and blood pressure. J. Clin. Biochem. Nutr 2010; 48(1)
5. Heinrich et al. Long-Term Ingestion of High Flavanol Cocoa Provides Photoprotection against UV-Induced Erythema and Improves Skin Condition in Women. JN 2006; 1565-1569
6. Heiss et al. Improvement of Endothelial Function with Dietary Flavanols is Associated with Mobilization of Circulating Angiogenic Cells in Patients with Coronary Artery Disease. JACC 2010; 56(3)
7. Hellenberg, “Vascular Action of Cocoa Favanols in Humans: The Roots of the Story” J Cardiovasc PharmacolTM Volume 47, Supplement 2, 2006
8. Hooper et al. Flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials. Am J Clin Nutr 2008; 88: 38-50.
9. Hung et al. Fruit and Vegetable Intake and Risk of Major Chronic Disease. JNCI J Natl Cancer Inst 2004; 96 (21): 1577-1584
10. Praag et al. Plant-Derived Flavanol (-)Epicatechin Enhances Angiogenesis and Retention of Spatial Memory in Mice. The Journal of Neuroscience, 2007; 27(22):5869-5878
11. Ramirez-Sanchez et al. (−)-epicatechin activation of endothelial cell endothelial nitric oxide synthase, nitric oxide, and related signaling pathways. Hypertension 2010; 55: 1398-1405.
12. Reznichenko et al. Green tea polyphenol (-)-epigallocatechin-3-gallate induces neurorescue of long-term serum-deprived PC12 cells and promotes neurite outgrowth. J. Neurochemistry 2005; 93(5)
13. Schroeter et al. (-)Epicatechin mediates beneficial effects of flavanol-rich cocoa on vascular function in humans. PNAS 2006; 103(4)
14. Steffen Y. et al. (-)-Epicatechin elevates nitric oxide in endothelial cells via inhibition of NADPH oxidase. Biochem Biophys Res Commun 2007; 359: 828-833.
15. Werner et al. Circulating Endothelial Progenitor Cells and Cardiovascular Outcomes. N. Engl. J. Med. 2005; 353(10)

• Endothelial dysfunction = Pathological state of the endothelium (the inner lining of our blood vessels). Cardiovascular risk factors cause oxidative stress that alters the endothelial cells’ capacity and leads to endothelial “dysfunction”, reducing its capacity to maintain homeostasis and leading to the development of pathological inflammatory processes and vascular disease. – Cardiovascular Diabetology 2006, 5:4
• Vasodilation = the widening of blood vessels via relaxation of smooth muscle cells within the vessel walls, resulting in increased blood flow and decreased blood pressure
• Procyanidins = polymers of flavonoids such as catechins (catechins such as (-)Epicatechin are the ‘building blocks’ of procyanidins)
• Chocolate – refers to combination of cocoa, cocoa butter, sugar, etc. into solid food product (Cooper, Cocoa and health: a decade of research)
Heiss C, Jahn S, Taylor M, Real WM, Angeli FS, Wong ML, Amabile N, Prasad M, Rassaf T, Ottaviani JI, Mihardja S, Keen CL, Springer ML, Boyle A, Grossman W, Glantz SA, Schroeter H, & Yeghiazarians Y (2010). Improvement of endothelial function with dietary flavanols is associated with mobilization of circulating angiogenic cells in patients with coronary artery disease. Journal of the American College of Cardiology, 56 (3), 218-24 PMID: 20620742
Fraga CG, Litterio MC, Prince PD, Calabró V, Piotrkowski B, & Galleano M (2011). Cocoa flavanols: effects on vascular nitric oxide and blood pressure. Journal of clinical biochemistry and nutrition, 48 (1), 63-7 PMID: 21297914