Coronary artery disease (CAD) is among the leading causes of death and reduced quality of life in developed countries. Approximately 67 million U.S. adults have high blood pressure (hypertension), with an additional 85 million Americans classified as having pre-hypertension. Hypertension, atherosclerosis and other inflammatory conditions are major contributors to the development of cardiovascular disease (CVD). Prevention and treatment of CAD start with diet. While long-term changes in lifestyle and diet are very good at controlling CAD, many Americans find them difficult to follow, and they are even becoming heavier in the process.
Cocoa has been around for thousands of years, dating back to the Incas and Aztecs around 1600 BC. The Aztec emperor Montezuma supposedly drank cocoa to fight fatigue. Cocoa was thought to have health benefits, ranging from an aid in digestion, relief of angina to improving kidney and bowel function. It was also thought to treat the following:
- anemia
- mental fatigue
- fever
- gout
- tuberculosis
Epidemiological research has shown that a diet robust in fruits and vegetables can prevent or delay the onset of CVD. Many researchers wondered what components of fruits and vegetables are responsible for the possible health effects. Flavanols are abundant in certain fruits and vegetables, leading researchers to focus attention on plants with a higher concentration of flavanols. Foods with higher flavanol content include:
- chocolate
- beans
- apricots
- cherries
- peaches
- green and black tea
- red wine
Recent clinical trials are now re-visiting the possible health benefits of cocoa. One epidemiological study focused on the Kuna Indians living off the coast of Panama. In addition to a salt enriched diet, the Kuna Indians consume massive amounts of cocoa daily. However, death from cardiovascular events is significantly lower than for other Pan-Americans. Scientists have found Kunas have lower blood pressure and no decline in kidney function with age. Apparently, when Kunas move to the mainland, they eat less cocoa, and the protective effect vanishes. Additionally, a Dutch trial studied a group of elderly men whose risk of dying from CVD decreased by 50% while consuming high amounts of cocoa.
Cocoa Helps to Lower Cholesterol, Reduce Blood Pressure, and Improve Coagulation
High blood pressure is due to increased resistance to blood flow throughout the body. Catecholamines, angiotensin-II, vasopressin, prostaglandins and nitric oxide (NO) all help regulate vascular tone and resistance. Reportedly, a high flavanol cocoa beverage increases NO, causing vasodilation, better blood flow and reduction in blood pressure. Several studies have replicated this effect. However, the dilating effect may be short-term. The kidney is the main blood pressure regulator, and cocoa's effects must also lower the kidney's sodium threshold for any long-term effects.
Cardiovascular disease and CAD develop from increased low-density lipoprotein (LDL) cholesterol and decreased high-density lipoprotein (HDL) cholesterol. Several studies speculate that cocoa works to decrease LDL by stopping the absorption of cholesterol from the gastrointestinal tract, inhibiting liver production of LDL, lowering liver secretion of precursors to LDL and increasing liver uptake of LDL. Changes in HDL are conflicting with some studies reporting an increase and others show no effect at all.
Coagulation (blood clotting) plays a major role in the development of CVD. Unstable plaques, caused from high cholesterol, rupture and release a clot, leading to heart attacks and strokes. Apparently, cocoa stops platelets from forming clots, helping reduce the prevalence of cardiovascular events. It has been noted that beneficial effects of cocoa are only seen in people with pre-existing cardiovascular risks or disease.
Not All Forms of Chocolate are Created Equal for Heart Disease
Chocolate is manufactured using a blend of cocoa beans from around the world, producing an inconsistency in the beneficial flavanol content. Epicatechin is the flavanol in cocoa linked to all the beneficial effects. Different parts of the world produce cocoa beans with varying amounts of epicatechin. Likewise, fermentation, roasting and alkali treatments used during production to enhance flavor reduces flavanol content. For this reason, chocolate and powder with a higher cocoa content are the ones shown to have more beneficial cardiovascular effects. Dark chocolate (50% to 71% cocoa content) and cocoa powder have the highest flavanol content, with milk chocolate possessing the least. White chocolate has little to no flavanol content.
Americans have a difficult time sticking with therapeutic lifestyle changes. Chocolate is a favorite treat for many, but has been vilified in recent history for adding to the problem of obesity, diabetes, and heart disease. However, recent evidence suggests that moderate doses of dark and sugar free chocolate may indeed help with these problems, allowing for some flexibility in difficult lifestyle changes. As always, speak with a doctor and pharmacist before changing diet or medicines.
References:
Galleano M et al. Cocoa, chocolate, and cardiovascular disease. I Cardiovasc Pharmacol 2009;54(9):483-490.
Corti R et al. Cocoa and cardiovascular health. Circulation 2009;119:1433-1441.
Egan BM et al. Does dark chocolate have a role in the prevention and management of hypertension? Hypertension 2010;55:1289-1295.
Jia L et al. Short-term effect of cocoa product consumption on lipid profile: a meta-analysis of randomized controlled trials. Am J Clin Nutr 2010;92:218-225.
Disclaimer
The information in this article is for educational purposes only. Always seek the advice of your healthcare provider prior to starting or stopping any medicine or treatment.
Katrin Holt - My name is Katrin Holt, and I am a pharmacist that loves to write about disease states and the medicines used to treat them. I graduated ...
