In recent years much has been written about the health value of dark chocolate. Much—but not all—chocolate contains a class of so-called “flavinoids,” or “flavanols,” which are widely present in cocoa, green tea, red wine and some fruits. These components seem to be helpful in lowering blood pressure and improving cardiovascular health. Most research indicates that cocoa or dark chocolate, consumed daily, produce beneficial effects on human health, consisting of a modest reduction in blood pressure with dilation of arteries, resulting in increased circulation to various organs (the brain for one, perhaps most notably). Consuming milk chocolate or white chocolate, or drinking fat-containing milk with dark chocolate, appears to largely negate the various health benefits.
For instance, survivors of heart attacks who eat chocolate at least two or three times a week reduce their risk of death by a factor of up to three times compared to survivors who did not eat chocolate. These apparently beneficial effects seem to derive from the positive role of cacao and cocoa products on cardiovascular risk factors such as blood pressure, cholesterol levels, atherosclerosis, and improving how the body handles insulin (potentially helping diabetes, another potent risk factor).
But the picture is not without drawbacks, for over-consumption of chocolate can have harmful effects such as weight gain and obesity. Moreover, chocolate that contains the most flavanols seems to confer the most benefit, whereas that being poor in these components possess little, if any, benefit.
EFFECTS ON BRAIN FUNCTION
Recently, researchers from Columbia University in New York gave 37 trial participants, aged between 50 and 69, a drink containing cocoa for which flavonols were extracted from cocoa beans. The amount of flavonols consumed varied: Half of the participants received 900 mg daily; the other half received only ten milligrams.
Then the scientists measured the blood flow in the brain. In the flavonol-rich group, a higher circulation was found. Moreover, the participants of this group achieved significantly better results in memory tests. If a participant had the memory of a typical 60-year-old at the beginning of the study, “after three months that person on average had the memory of a typical 30- or 40-year-old”, said study author Scott Small. However, the study did not include participants with dementia or similar conditions, but did include people with healthy memory and age-related memory declines, the authors emphasized.
Supporting of these findings, another study of thirty–two healthy participants underwent two baseline sessions after one night of undisturbed sleep and two experimental sessions after one night of total sleep deprivation. Two hours before each testing session, participants were randomly assigned to consume high or low flavanol chocolate bars. Indirect measures of blood flow to the brain were also studied.
Interestingly, after sleep deprivation, those who received high flavanol chocolate showed no decrease in the expected loss of memory, whereas those receiving low flavanol chocolate failed to retain memory in much the same way as normal loss of sleep produces. Moreover, these results correlated with changes in blood flow to the brain, i.e., those receiving high flavanol chocolate showed evidence of more blood flow to this organ.
Not All Chocolate Is Created Equal, but greater Benefits likely from more Flavanol
One of the biggest challenges in comparing the research on chocolate and health is the wide variety of the types of chocolate consumed. While clinical trials most often use dark chocolate, which can vary greatly in flavanol content, epidemiologic studies have examined overall chocolate consumption, including dark and milk chocolate. Unfortunately, flavanol-rich cocoa and chocolate products have a distinctly bitter taste.
Milk chocolate, which is the most widely consumed chocolate in the United States, is much lower in flavanols than dark chocolate. But even dark chocolate can vary greatly in flavonol content, depending on the amount of cocoa solids it contains and how it’s processed. Flavanol content even varies among crops of cacao beans. Manufacturers typically purchase cacao beans from several countries and from many suppliers and then combine them. This practice results in varying flavonoid levels from batch to batch of chocolate produced.
The labeling of the flavanol content of chocolate products isn’t mandatory, but as a general rule, the higher the percentage of cocoa solids in a chocolate product and the more bitter the taste, the higher the flavanol levels. But while this association isn’t consistent, it‘s the best indicator available of flavanol content. And then, of course, there’s white chocolate, which isn’t chocolate at all; it contains zero flavanols.
So what should the individual do about chocolate? Be aware that most chocolate products are high in sugar, fat, and calories. While much of this fat is the kind that doesn’t raise cholesterol levels, it does add a significant number of calories. It’s not wise to add a daily dose of chocolate if it’s not already part of your diet, especially if you’re overweight or obese. However, some researchers have suggested that if total calorie intake is balanced, chocolate flavanols can be part of a healthful diet in general, especially for those with high blood pressure. If you are a chocolate lover who regularly indulges, choose dark chocolates that are high in cocoa solids and therefore usually rich in heart-healthy flavanols. Increasingly, dark chocolate products are providing the percentage of cocoa solids on the label, and some newer varieties, such as CocoaVia, are even listing the amount of flavanols on the label, boasting as much as 350 mg per serving.
Despite these touted health benefits, Americans overwhelmingly prefer the taste of milk chocolate over dark—and we’re not alone. A study from Australia found that one-half of the participants in a 24-week period said it was hard to eat 50 g (about 3 oz) of dark chocolate every day, and 20% said it was an unacceptable long-term treatment option. Yet the truth is the darker the chocolate, the more bitter the taste and the more healthful it is for the heart. What a bummer!
The bottom line? Clearly, not everyone is a fan of dark chocolate, but it’s the one to consume for heart health. Eating too much chocolate, like any high-calorie snack, can have harmful effects, but the research strongly suggests a potential health benefit from regular consumption of dark, flavanol-rich chocolate as part of a healthful diet. But the refrain from researchers is the same: We need more research before we can make any definitive recommendations.