Study published within the journal Scientific reports shows that dark chocolate consumption can significantly reduce the chance of essential hypertension. Essential hypertension is hypertension that’s multifactorial and has no clear cause.

Test: Dark chocolate consumption and heart problems: the Mendelian randomization study

Background

Heart problems is a number one reason behind disability and mortality worldwide and is a significant contributor to the worldwide burden of disease. The estimated total variety of cases of heart problems in 2019 was 523 million, with the very best incidence within the Middle East and North Africa and the very best mortality in Central Asia and Eastern Europe.

Given the high morbidity and mortality related to heart problems, several studies have been conducted to discover each risk aspects and preventive measures. Some small-scale, randomized, controlled trials have shown that dark chocolate advantages cardiovascular health. The three primary flavanols present in dark chocolate, including procyanidin, catechin, and epicatechin, are known to have helpful effects on the cardiovascular system.

On this study, researchers examined the causal relationship between dark chocolate consumption and the chance of heart problems using the Mendelian randomization method. Mendelian randomization uses measured variation in genes of known function to look at the causal effects of modifiable exposure to disease in observational studies.

Study design

The researchers obtained summary data from a genome-wide association study of dark chocolate consumption from the MRC Integrative Epidemiology Unit (University of Bristol) website. The information included 64,945 participants of European descent. They identified 21 independent single-nucleotide polymorphisms as instrumental genetic variables predicting dark chocolate consumption. An instrumental variable is a sort of variable that mustn’t have a direct impact on the consequence.

As well as, researchers obtained summary data on heart problems from various publicly available genome-wide association studies. They synchronized datasets of dark chocolate consumption and heart problems to find out the allelic direction of single-nucleotide polymorphisms in each cases.

They then analyzed the info to find out the causal relationship between genetically predicted dark chocolate intake and the chance of 12 cardiovascular diseases, including heart failure, ischemic heart disease, myocardial infarction, atrial fibrillation, nonrheumatic valvular disease, nonischemic cardiopathy, significant hypertension, venous thromboembolism, deep vein thrombosis, stroke, ischemic stroke and transient ischemic attack. In addition they performed sensitive analyzes to evaluate the reliability of the outcomes of the Mendelian randomization evaluation.

Necessary observations

The study results showed that dark chocolate consumption significantly reduces the chance of essential hypertension. The study observed a suggestive negative association between dark chocolate consumption and the chance of venous thromboembolism. No significant association with dark chocolate consumption was observed for other cardiovascular diseases examined.

Importance of the study

This study shows that genetically predicted dark chocolate intake is significantly related to a lower risk of essential hypertension and is suggestively related to a lower risk of venous thromboembolism.

Available evidence indicates that flavanols present in dark chocolates may improve endothelial function, promote vasodilation, and stop platelet aggregation by increasing the discharge of nitric oxide. Flavanols are also known to have strong antioxidant and anti inflammatory effects. All of those actions of flavanols are believed to be major contributors to a healthy cardiovascular system.

The hypertension data utilized in this study include cases of secondary hypertension, which is basically a symptom of kidney disease, renal vascular disease, and certain endocrine diseases of the cardiovascular system. Nonetheless, the study didn’t examine the causal relationship between these diseases and the consumption of dark chocolate. That is why scientists advise to not rely solely on dark chocolate to stop essential hypertension. Quite the opposite, people at high risk of hypertension can replace unhealthy snacks with dark chocolate to enhance their cardiovascular health.

Because the researchers mentioned, this study used a small sample of exposure data. The one nucleotide polymorphisms identified also didn’t meet the standard genome-wide significance threshold. Nonetheless, these single nucleotide polymorphisms may be considered effective instrumental variables because their Fisher statistic values ​​(a measure of the ratio of variances) are greater than 10. To reject the null hypothesis, a Fisher statistic value greater than 2.5 is required. Furthermore, results from sensitive analyzes demonstrated the robustness of the causal effect estimates for just about all outcomes.

The study used summer data on European ancestral populations. This limits the power to generalize research results to other populations.

Overall, the study provides priceless information on the prevention of essential hypertension in the overall population. Further clinical studies are needed to obviously establish a causal relationship between dark chocolate consumption and the chance of heart problems.