Dark Chocolate and Heart Disease
Chocolate grabs our attention in a headline with heart disease in a way that apples and apricots just don’t. The juxtaposition of the words “dark chocolate” and “disease prevention” may be startling and attractive because we associate chocolate with special occasions or falling off the diet wagon, not making our cardiologists happy. Marketers have touted chocolate as beneficial, but for many of us, this sounds too good to be true.
Does research support chocolate’s salubrious effects?
Research has demonstrated that eating or drinking chocolate products is associated with lower blood pressure and a decreased risk of mortality from heart disease. In fact, scientists in the Netherlands found regular intake of chocolate was associated with a 45-50% lower risk of all-cause mortality. Well then, is the research conclusive we should all be eating more chocolate? Research studies on chocolate are typically conducted in one of two ways. There are short-term experimental trials where participants consume chocolate and measures of health related indices (e.g., blood pressure) are taken a short time later. Large epidemiological studies have also been done, which include data on how much chocolate people eat. These are conducted over longer periods and assess chocolate consumption and rates of disease. Researchers then use statistical methods to tease out confounding variables like smoking, body weight, physical activity, and other types of food consumption. These studies are much more common in the scientific literature studying chocolate’s role in health.
In one short-term experiment, researchers somehow managed to find participants in Connecticut who were willing to drink cocoa or eat chocolate bars in the name of science. It turns out that significant blood pressure decreases were found in this sample soon after consuming chocolate products high in cocoa. Congruent with this trial are epidemiological studies that indicate higher chocolate consumption is associated with lower rates of death from heart disease. So in short true experiments we have a great deal of control. Researchers know exactly what participants are putting in their mouths and they know the precise changes in physiology. But in those studies we don’t know the rates at which disease develops over the years or what else participants are doing over that time. In large observational studies participants report what they eat, but we can’t be as confident what they remember eating over the years is accurate. We do know the rates of disease that are correlated with what they said they ate, but there are many other variables that get thrown into the mix that could confuse the findings. To be really confident that chocolate consumption is related to cardiovascular health, we would need participants to be randomly assigned to different levels of chocolate consumption, to stick to that level for years, and see what happens. Now imagine trying to get some chocolate lover out there to go without chocolate for years if they are in the study? Or imagine anyone you know who is constantly dieting agreeing to participate, when he/she might be thrown into the high chocolate group. This presents quite a dilemma for science. But even with these research challenges, the data still point to benefits from cocoa. How could that be?
What is in chocolate?
Chocolate is made from cocoa beans. Cocoa beans contain flavonoids, specifically flavanols. Flavanols have antioxidant and anti-inflammatory properties. These characteristics appear to be what gives some chocolate products their healthy effects. While chocolate bars and drinking cocoa both yielded decreases in blood pressure in the aforementioned study, all chocolate products are not created equal.
Dark Chocolate, Milk Chocolate, or White Chocolate?
Cocoa beans are processed in order to produce cocoa solids and cocoa butter. Chocolate bars will typically contain both of these, but in various ratios. Dark chocolate contains a higher percentage of solids. Flavanols reside in the solids. That is the reason dark chocolate and cocoa powder are likely better choices than milk chocolate or white chocolate, if heart health is the goal. Milk chocolate has a lower percentage of solids than dark chocolate, and white chocolate does not contain any solids. That is the reason dark chocolate gets the healthy reputation. But it is important to note that dark chocolate contains cocoa butter and can contain many other ingredients, so it can have high levels of sugar and fat.
Is milk chocolate bad?
Unless you have an allergy or a medical condition that prohibits eating milk chocolate, one bar is unlikely to be detrimental. In fact, if a physician has given you the go ahead, and you really enjoy milk chocolate, it could even benefit your mental health since frequent pleasurable experiences help reduce depressive symptoms. But like any food, these treats need to be seen in the context of one’s medical profile and overall caloric and nutrient intake. Chocolate is an energy dense food (i.e., highly caloric) and it is easy to imagine how an occasional treat could grow into a regular staple. When working with patients to change lifestyle habits like nutritional intake, I am always sure they are doing so within parameters set by their physician. My approach to chocolate is somewhat similar to that of alcohol. If the patient hasn’t included it as part of his/her diet up until that point, I don’t typically recommend he/she start, since flavanols can be found in other products (e.g., some fruits and green tea). While chocolate and alcohol can be difficult for some to moderate, I don’t anticipate too many clients struggling to resist or gaining weight from apricot and green tea binges. So initiating a chocolate habit probably isn’t necessary for the health benefits. But for those already eating chocolate, I want to make sure the amount and frequency fit within his/her nutrition plan and that eating chocolate doesn’t occur in response to stress or negative emotions. Once that is the case, experimenting with higher levels of cocoa (and lower levels of fat and sugar) may be worth the effort. For those eating milk chocolate, that could mean trying dark chocolate every other time. For those already eating dark chocolate, exploring higher percentages of many commercially available bars could lead to leaving your old “sweet spot” and discovering an appreciation for a more bitter chocolate bar rich in flavanols. If chocolate bars aren’t your thing, unsweetened cocoa could be a way of getting those flavanols in your system. Chocolate nibs, the inside of the cocoa bean, have also become widely available. Some are covered in sweeter chocolate, so be sure to look at the ingredients to match the food to your nutrition plan. For chocolate consumers, gradually exploring products with higher flavanol content could improve your health, and might even be fun. But chocolate products often contain high levels of calories and saturated fat, so be sure your physician approves your plan.
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