Cocoa and its processed food product chocolate are believed to improve the function of endothelial cells, and thereby reduce blood pressure. Several studies have been conducted across the world to identify the health-related benefits of consuming chocolate.

In the present review, the researchers summarized the findings of several studies conducted to investigate the beneficial effects of cocoa in the maintenance of cardiovascular health.

Cocoa has traditionally been used in the treatment of various illnesses. However, its use for medicinal purposes has declined in recent years. Many studies have been conducted across the world to rediscover the medicinal value of cocoa.

Almost all of these studies could recognize the health-promoting effects of chocolates, which are prepared from cocoa. Chocolates are a rich source of antioxidants such as polyphenols, particularly flavonoids, which constitute about 8 percent of the dry weight of cocoa beans. The exact amount of antioxidants depends on the type of cocoa beans and the method of handling and processing them after harvesting. Flavonoids such as flavanol are known to reduce the risk of coronary heart disease.

Chocolates are consumed by most people all over the world. Hence, the researchers of the present study investigated the health benefits of the consumption of cocoa. They also tried to identify the mechanisms through which cocoa may confer its beneficial effects.

In the present review, the researchers evaluated various studies that were conducted to examine the health benefits of the consumption of cocoa.

The first set of articles was based on epidemiological studies that observed the occurrence of hypertension in people who consumed cocoa. Some studies involved the assessment of blood pressure changes in tribal people who drank large quantities of cocoa.

The second set of articles consisted of studies that were done to understand the mechanism of the action of cocoa. This set of articles predominantly involved studies on rats.

Results/Key findings
* In the Stockholm Heart Epidemiology Program, which assessed the long-term effects of chocolate on patients with coronary heart disease, it was observed that chocolate consumption reduces the risk of mortality due to cardiovascular diseases. The average reduction in systolic and diastolic blood pressures was 4.5 mm Hg and 2.5 mm Hg, respectively, in those who consumed cocoa products.

* Kuna Indians, who consume large quantities of cocoa, are immune to hypertension in spite of consuming large quantities of salt. However, people of the same community who consume less cocoa suffer from hypertension.

* Experiments on rats showed that administration of cocoa to hypertensive rats reduces their blood pressure. This is probably because of the release of nitric oxide from the endothelial cells in blood vessels, which prevents fat deposition in the arteries.

Shortcomings/Next steps
The number of studies on the effects of cocoa is significantly small. Moreover, the studies had very small sample sizes. There are different types of flavonoids present in different cocoa beans and their concentrations differ depending on the method of processing.

Further studies must consider these factors. Clinical trials at different stages are also needed before recommending cocoa for the treatment of hypertension.

The incidence of hypertension is increasing at an alarming rate and cardiovascular diseases are at present the leading cause of death across the world. Important measures for controlling blood pressure include lifestyle modification and dietary control.

The present review highlights one of the dietary measures that can be undertaken to prevent the incidence of hypertension. One of the reviewed studies shows that reduction in blood pressure because of consumption of cocoa is equal to the reduction produced by Captopril, a well-known antihypertensive drug.

The authors of this review conclude that changes in blood pressure in response to the flavonoids present in cocoa in both healthy and hypertensive individuals suggest that including moderate amounts of flavonoid-rich cocoa might be beneficial in preventing hypertension.