The chocolate you eat starts as a cacao bean. After processing, it can be made into various chocolate products. The less the beans are processed, the more polyphenol properties they retain. Polyphenols are antioxidant plant-derived chemicals, including flavonoids. Flavonoids can be found in lots of foods other than chocolate, including fruits and vegetables. These compounds are behind many of the claims that chocolate may be beneficial in addressing precursors to heart disease, including lowering blood pressure and cholesterol and keeping your blood flowing smoothly.
Choosing Chocolate
Depending on how it's processed, chocolate can be sold in various forms, such as milk chocolate, white chocolate or dark chocolate. High-flavonoid cocoa or minimally processed dark chocolate has the highest amount of healthful antioxidants, while milk chocolate and Dutch-processed cocoas have the lowest. One way to determine the relative amount of flavonoids in your chocolate product is to check the ingredients list. If cocoa solids or mass or chocolate liquor is the first ingredient, rather than sugar, you're on the right track. Chocolate products often feature a percentage number on their label: for example, 72 percent dark chocolate. This refers to the percentage of cocoa mass in the product. The remaining 28 percent, in this instance, would be sweeteners.
Blood Pressure
Scientists have known for some time that cocoa can help lower blood pressure, but doctors have been reluctant to recommend adding chocolate to their patients' diets because of the added sugar. Researchers say that eating dark chocolate may prove to be a more effective behavioral change for people with cardiovascular disease than asking them to follow more restrictive dietary guidelines.
In a study reported in 2007 by the "Journal of the American Medical Association," researchers found that a 30-calorie, 6.3-g dark chocolate bar containing 30 mg of polyphenols helped reduce blood pressure. Though the blood pressure reduction was small, the researchers noted that even a three-point decline can cut the risk of stroke and heart attack.
Chronic high blood pressure is a major risk factor for heart failure. In a 2010 study reported by the American Heart Association, or AHA, middle-aged and elderly women who consumed a moderate amount of chocolate, defined as no more than one to two servings a week, were found to have lowered their risk of heart failure.
Cholesterol
In addition to lowering blood pressure, dark chocolate has also been linked to improved cholesterol numbers. In a preliminary analysis reported at the March 2011 conference of the AHA, researchers found that a certain type of sugar-free chocolate lowered bad cholesterol and raised good cholesterol in people younger than 50. Scientists cautioned that they used a specially processed type of cocoa and that they do not know the right amount of chocolate to ingest to balance the health benefits with the risks associated with potential weight gain.
Blood Circulation
Another way that dark chocolate affects your cardiovascular system is by keeping your blood circulating. In 2007, researchers at Harvard found that dark chocolate, but not other kinds, widened arteries and made platelets --- a component of blood --- less sticky. Keeping blood flowing smoothly through the arteries means you are less likely to have a stroke or heart attack.
Chocolate in Your Daily Diet
The cacao bean is quite bitter, so the chocolate you eat usually has lots of added sugar and sometimes added fat to make it taste good. One European study found that a small snack of dark chocolate, as opposed to milk chocolate, gives people more of a sense of feeling full, so they are less likely to overeat. In general, though, healthcare professionals continue to be concerned that chocolate consumption will contribute to the obesity epidemic in the U.S.
The AHA is wary that many of the studies about chocolate will be misunderstood or misused. The organization has issued a statement reminding people that a snack of even the darkest chocolate won't make up for other poor eating habits. It's okay to eat chocolate in moderation, keeping in mind the AHA recommendation of limiting your consumption of added sugars to about 100 to 150 calories per day. Focus on eating a well-balanced diet with plenty of fresh fruits and vegetables -- many of which also have flavonoids and other antioxidants.