Since ancient times cocoa has been acknowledged for its numerous health benefits. Significant clinical data has demonstrated that diets rich in nutrients such as fruits and vegetables promote health effects and delay onset of various disease conditions. Moderate consumption of cocoa containing foods and chocolate are now considered part of healthy diet. Already since 18th century cocoa was considered beneficial for heart diseases but this was not supported by scientific evidence.
However, cocoa and chocolate have been extensively studied in last few years and various studies have shown that cocoa containing foods and chocolate are rich in various bioactive chemicals that interact with cells and tissue components of the body and provide protection against the development of various diseases. The most relevant effect of cocoa and chocolate has been related to cardiovascular disease (CVD). Cocoa is a rich source of compounds known as flaven-3-ols or flavenols, catechins and procyanidins. Flavenols are the compounds which are present in high concentrations not only in cocoa but also present in grapes, apples, pomegranate and tea and among other widely consumed fruits and vegetables.
Studies have revealed that biochemical mechanisms contributing to the health effects of flavenols include; antioxidant effects (antioxidants are substances that can prevent or slow the damaged to cells caused by unstable molecules produced in the body), flavenols and procyanidins present in the circulation can improve Nitric Oxide (NO) vascular concentration (NO availability is crucial for relaxation of muscles in the blood vessels).
Previous short-term studies indicated that cocoa-containing foods improve endothelial function (endothelium is a thin membrane that lines the inside of the heart and blood vessels; endothelium cells release substances that control vascular relaxation and contraction, control blood clotting and immune function etc.) and helps reduce blood pressure. These lead researchers to conduct the studies with an objective to evaluate whether habitual cocoa intake from consumption of cocoa –containing foods was inversely related to blood pressure and cardiovascular mortality (inverse association is relationship between two variables such that when one variable is high the other is low and vice versa).
[Blood pressure is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart, pumping blood through the circulatory system. Systolic blood pressure indicates the pressure exerted against the artery walls when the heart beats. Whereas, diastolic blood pressure indicates the pressure in the artery walls while the heart is resting between the beats. In most people systolic blood pressure rises steadily with age due to increasing stiffness of large arteries and long-term fat deposits inside the blood vessels. Uncontrolled, high blood pressure is a major risk factor for development of cardiovascular disease.]
[Cardiovascular diseases (CVDs) are a group of disorders that involve heart and blood vessels. It usually occurs due to deposition of fat deposits in the blood vessels over time which affects the blood flow. Some examples are:
*Coronary heart disease which is the disease of blood vessels supplying the heart muscles.
*Cerebrovascular disease which is the disease of blood vessels supplying the brain tissue.
*Congenital heart disease occurs due to malformations of heart structure existing at birth.
CVDs can be fatal and can lead to acute events like heart attacks and stroke which are life threatening situations and can also cause permanent disability.]
Evidence of beneficial effects of cocoa were gained from the Zutphen Elderly study that included elderly men, who were free of chronic diseases at baseline. To conduct the studies their blood pressure was measured at baseline and 5 years later and causes of death were ascertained during 15 years of follow-up. Furthermore, habitual food consumption was assessed in 1985, 1990 and 1995. Cocoa intake was estimated from consumption of cocoa-containing foods. One-third of the men did not used cocoa at baseline. The average cocoa intake among the users was 2.11 g/dl.
The analysis of the study data revealed that participants with significant cocoa consumption or with a usual daily cocoa intake of about 4.2 g which is equal to 10 g of dark chocolate per day had a lower systolic and diastolic blood pressure when compared to participants with a low cocoa intake.
In the light of these findings researchers concluded that, this study conducted on elderly men showed that habitual cocoa intake is inversely associated with blood pressure; and 15-year follow-up has shown that cocoa intake is inversely associated with cardiovascular mortality and all-cause mortality as well.
Researchers suggested that flavenols in cocoa containing food are likely to be responsible for reduction in blood pressure and improvement of endothelial function. An increased activity of nitric oxide is likely to play a major role in this process. Moreover, other bioactive substances in cocoa may also contribute to its effects.
Cocoa Intake, Blood Pressure, and Cardiovascular Mortality:
The Zutphen Elderly Study
Cocoa, Chocolate and Cardiovascular disease