Can cocoa reduce the risk of cardiovascular disease?

In a recent study published in the journal Nutrients, researchers examined the effects of cocoa consumption on anthropometric measurements, blood pressure, glycemic and lipid profiles to understand its impact on cardiovascular disease (CVD) risk.

Current estimates indicate that CVDs claim more than 17.9 million lives each year, making them the leading global cause of death. In Brazil, more than 397,000 people died from CVDs in 2019, 43% of whom died from ischemic heart disease.

The Framingham Heart Study is considered a pioneer of cardiometabolic research, as much of the current cardiometabolic risk stratification is based on its concepts. This study stratified CVD risk based on age, sex, systolic and diastolic blood pressure, cholesterol, body mass index (BMI), and behaviors including smoking and alcohol dependence. Notably, many of these factors have shown strong associations with diet, with a growing body of literature highlighting the role of healthy diets, such as the Mediterranean diet, in reducing CVD risk.

Cocoa is a fruit rich in polyphenols, most of which are flavonoids, which have been shown to reduce the risk of both CVD and atherosclerosis by reducing inflammation, improving endothelial function, and lowering blood pressure. More specifically, cocoa appears to activate nitric oxide (NO) and neutralize free radicals, thereby reducing oxidative stress and protecting cells from damage.

To date, previous studies aimed at identifying potential benefits of cocoa consumption on the Framingham risk score, a measure of cardiometabolic risk, have yielded mixed results.

This study conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) assessing the association between cocoa consumption and cardiometabolic risk markers.

RCTs involving individuals aged 18 years or older consuming cocoa, cocoa extracts, or dark chocolate with a cocoa content of 70% or higher were included in the review. Studies in pregnant or postmenopausal women, animal models, and studies examining the association between cardiometabolic risk and other co-morbidities such as cancer were excluded.

Six electronic scientific databases were used to identify relevant publications, including MEDLINE, Web of Science, EMBASE, SciELO, LILACS and Cochrane. Rayyan reference manager was used to extract and manage study data.

Of the 3807 studies initially identified in the database, 31 met the inclusion criteria and were included in the meta-analysis. Collectively, these studies included a cohort size of 1110 cases and 876 controls.

Thirteen studies assessed the effects of cocoa consumption in healthy participants, three in participants with metabolic syndrome, two in hypertension or prehypertension, seven in T2D, one in insulin resistance, and four in dyslipidemia or overweight.

Cocoa consumption had no statistically significant effect on total body weight, waist circumference, or BMI. Although abdominal circumference decreased after cocoa interventions, these results were borderline and associated with high heterogeneity.

However, cocoa polyphenol consumption was associated with reductions in adverse lipid profiles, fasting glucose levels, and blood pressure, with the extent of reduction positively correlated with cocoa dosage. These results may explain previously conflicting reports between studies, as cocoa exerted cardioprotective effects despite a lack of improvement in some CVD risk markers.

Overall, cocoa consumption, including cocoa supplements and dark chocolate, has a protective effect on cardiometabolic risk markers and has a clinically significant effect on reducing CVD risk.

"We propose that consumption of polyphenol-containing cocoa could be part of a strategy to promote cardiovascular health."