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Chinese scientists undertook a study to examine how dark chocolate affects heart health and to verify if it truly can prevent cardiovascular diseases. The results were published in the journal Scientific Reports.
Previous Works on Dark Chocolate and the Heart
Cardiovascular diseases stand as a leading cause of disability and mortality worldwide, constituting a significant burden on global health. Estimates suggest that the total number of cardiovascular disease cases in 2019 reached 523 million. They are most prevalent in the Middle East and North Africa, with the highest mortality rates recorded in Central Asia and Eastern Europe.
Numerous studies have been dedicated to identifying risk factors and preventive measures. Some small randomized controlled trials have shown that dark chocolate is beneficial for cardiovascular health. This effect has been associated with three key flavonoids present in this chocolate: procyanidin, catechin, and epicatechin, all of which have a favorable impact on the cardiovascular system.
Research Design
In this study, scientists investigated the cause-and-effect relationship between the consumption of dark chocolate and the risk of cardiovascular diseases using Mendelian randomization. Mendelian randomization uses measured variation in genes of known function to examine the causal effect of a modifiable exposure on disease in observational studies.
The researchers obtained summary data from a genome-wide study on black chocolate consumption from the Department of Integrative Epidemiology at the MRC (University of Bristol). The data included 64,945 participants of European descent. Subsequently, the scientists acquired summary data on cardiovascular diseases from various publicly available genome association studies. Both sets of data on chocolate consumption and cardiovascular diseases were synchronized.
The analysis aimed to determine the cause-and-effect relationship between dark chocolate and the risks of twelve cardiovascular diseases. Among them were heart failure, ischemic heart disease, myocardial infarction, atrial fibrillation, non-rheumatic valve disease, non-ischemic cardiomyopathy, essential hypertension, venous thromboembolism, deep vein thrombosis, stroke, ischemic stroke, and transient ischemic attack.
Dark Chocolate Reduces the Risk of Essential Hypertension
Essential hypertension, or hypertensive disease, is characterized by multifactorial high blood pressure without a clear cause. Research results have demonstrated that black chocolate significantly lowers the risk of such hypertension.
Furthermore, the study observed a negative association between the consumption of dark chocolate and the risk of venous thromboembolism. No significant connection was found between dark chocolate consumption and other investigated cardiovascular diseases.
Scientific Conclusions
According to the authors, the available data suggest that flavanols present in dark chocolate may improve endothelial function, promote vasodilation, and prevent platelet aggregation by increasing the release of nitric oxide. Additionally, flavanols are known for their potent antioxidant and anti-inflammatory effects. It is believed that all these effects are key factors contributing to cardiovascular health.
The data on arterial hypertension used in this study include cases of secondary hypertension, which is typically a manifestation of kidney diseases, renal vessels, and certain endocrine disorders. However, the study does not investigate the cause-and-effect relationship between these conditions and the consumption of dark chocolate.
The authors advise against relying solely on dark chocolate for the prevention of essential hypertension. Instead, individuals at high risk may consider replacing it with more natural desserts. And most importantly, quantity matters.
