Chocolate for Heart Health

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Cacao may stave off cardiovascular disease

History of chocolate

Nothing says Valentine’s Day like a box of chocolates. In addition to being a token of affection, however, chocolate is also a medicinal super food that may support cardiovascular health. Perhaps it’s no wonder that we like to present chocolate in a heart-shaped box.

Let’s take a closer look at the studies on chocolate and heart health:

Cacao and cardiovascular health

A 2021 study by Zhong et al shows that eating cho­­colate may stave off death and disease.[1] In this study, 91,891 people ages 55 to 74 years were asked to complete food frequency questionnaires, and were then followed by the researchers for an average of 13.5 years.

The data showed an inverse relationship between chocolate consumption and mortality – meaning the people who ate chocolate were less likely to die from a variety of causes than the people who didn’t eat chocolate. This protective effect was particularly strong with respect to deaths from Alzheimer’s disease and cardiovascular disease.

The people who ate chocolate were less likely to die from a variety of causes than the people who didn’t eat chocolate.

The relationship was not linear, however: Eating greater more chocolate didn’t necessarily confer greater protection. The best results were seen with consumption of 0.6 to 0.7 servings of chocolate per week – with 0.6 servings per week being connected with the lowest risk of Alzheimer’s, and 0.7 servings per week correlating with the lowest risk of heart disease.

Curiously, the favorable benefits of chocolate eating were strongest among those who had never smoked cigarettes: Both current and former smokers were found to have less protection from chocolate eating than the never smokers.

The findings of this study confirm those of a 2020 prospective study by Sun et al, in which an examination of 84,709 postmenopausal women found an inverse relationship between chocolate consumption and all-cause mortality, Alzheimer’s, and cardiovascular disease.[2]

One limitation of these studies is that they did not distinguish between dark chocolate and milk chocolate consumption.

Zhong and Sun were not the first researchers to find that chocolate consumption may prevent cardiovascular disease.

A 2009 cohort study by Janszky et al observed 1,169 patients who had survived myocardial infarction (heart attack), finding that higher chocolate consumption was linked to lower mortality from cardiovascular disease – but not from all causes.[3]

Higher chocolate consumption was linked to lower mortality from cardiovascular disease.

Other prospective studies have also found that eating chocolate in low to moderate amounts (but not in big quantities) can lower the risk of atrial fibrillation[4] and heart failure.[5],[6]

A 2019 systematic review and meta-analysis of prospective studies (by Ren et al) sought to understand why some studies failed to find a connect between chocolate and heart disease. After reviewing 23 studies – including data from 405,304 participants and 35,095 cases of cardiovascular disease – the researchers found that the amount of chocolate consumed plays a key role in determining health benefits.

Eating less than 100 grams of chocolate per week reduced the risk of cardiovascular disease, whereas consuming greater than 100 grams weekly negated the health benefits.

Namely, it was found that eating less than 100 grams of chocolate per week reduced the risk of cardiovascular disease, whereas consuming greater than 100 grams weekly negated the health benefits – perhaps due to sugar content. When it comes to supporting heart health, the authors suggest 45 grams per week as the ideal dose of chocolate.[7]  (That’s about half of a typical bar of chocolate, or half as much as I ate while writing this article.)

How does it work?

Important components in cacao (the main ingredient of chocolate) are flavonoids (antioxidants), cocoa butter, phenylethylamine, caffeine, and theobromine.

The antioxidants abundantly found in cacao (the flavanols and polyphenols in particular), have been shown to support the blood vessels, modulate inflammation, reduce platelet aggregation (the propensity of blood to clot), and fight insulin resistance.[8]

Chocolate also improves the bioavailability of nitric oxide, a gas molecule that supports the health of our arteries and in turn improves blood pressure and blood fluidity.[9]

The caffeine and theobromine found in chocolate are methylxanthines, substances known to enhance cyclic AMP (cAMP). Cyclic AMP is important for the transmission of signals from cell to cell within the body. It’s perhaps for this reason that chocolate has been found to have neuroprotective effects.

Dark chocolate is healthier than milk

One limitation of many (though not all) of these studies is that they do not distinguish dark chocolate from milk chocolate.

Dark chocolate contains a significantly higher proportion of cocoa solids, and thus has more polyphenols.[10]

Milk chocolate, on the other hand, dilutes the salubrious constituents of dark chocolate with milk products and sugar. Dairy is a contentious food group, as it’s a common food allergy.[11] Milk has furthermore been found to reduce the body’s absorption of the antioxidants found in chocolate. Unsurprisingly, dark chocolate has been found to increase our total antioxidant capacity better than milk chocolate.[12]

Sugar is also a problematic ingredient, found in much higher quantities in milk chocolate than in dark chocolate. Sugar consumption has been linked with a host of diseases, including diabetes, fatty liver disease, cancer, and heart disease.[13],[14],[15],[16]

Dark chocolate confers greater health benefits than milk chocolate.

It has also been found that people who eat milk chocolate are likely to consume more than those who consume dark: A crossover study of 16 young men found that those who consumed dark chocolate felt more satisfied and were less likely to crave sweets later than those who ate milk chocolate.[17]

It’s therefore highly likely that dark chocolate confers greater health benefits than milk chocolate.

Indulge in moderation

While there are many benefits to eating chocolate, there are also some downsides. Chocolate can be a trigger food for those who experience migraines, and it can also exacerbate gastro-esophageal reflux (GERD, or heartburn).[18]

Chocolate may also worsen acne in those prone to getting pimples. In one study, 25 males prone to acne were asked to eat 25 grams of 99% dark chocolate daily for four weeks, and by the two-week mark it was clear that regular consumption of chocolate exacerbated their skin problems.[19]

It’s important to consider the time of day when reaching for a treat, as the caffeine in chocolate may compromise sleep quality if it’s eaten too late in the day. (Research suggests that caffeine should be consumed at least six hours before desired bedtime.)[20]

As with most things, moderation is key. Many of the studies on cardiovascular health report that eating low to moderate amounts of chocolate is likely better for the heart than eating large quantities. While chocolate is rich in antioxidants, it is also high in sugar, carbohydrates, and fat[21]  – nutrients that are linked with increased mortality.[22],[23],[24]

So, enjoy some dark chocolate this Valentine’s Day, but don’t eat the whole box on the fourteenth of February. Your heart will thank you for it.

References

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