Researchers in Boston examined data from a nine-year study of 31,823 women in Sweden to determine the effect of eating chocolate on heart disease and found that eating some of the sweet stuff may reduce the risk of heart failure.
The key findings:
- Women who ate an average of one to two servings of high-quality chocolate per week had a 32% lower risk of developing heart failure.
- Women who had one to three servings per month had a 26% reduced risk.
But women who ate at least one serving daily did not appear to benefit from a protective effect, probably due to the additional calories gained from eating chocolate instead of more nutritious foods, Murray Mittleman, MD, DrPH, of Harvard Medical School's Beth Israel Deaconess Medical Center, says in a news release.
"You can't ignore that chocolate is a relatively calorie-dense food and large amounts of habitual consumption is going to raise your risk for weight gain," he says. "But if you're going to have a treat, dark chocolate is probably a good choice, as long as it's in moderation."
High concentrations of compounds in chocolate called flavonoids may lower blood pressure, short-term studies have shown. But Mittleman, director of the Cardiovascular Epidemiology Research Unit at Beth Israel Deaconess, says the new study is the first to show long-term outcomes related specifically to heart failure, which can result from untreated high blood pressure over time.
The scientists studied self-reported chocolate eating tendencies of participants between the ages of 48 and 83 who were taking part in a long-term research project called the Swedish Mammography Cohort.
They combined the results with data from Swedish hospitalization and death registries between 1998 and 2006.
U.S. Chocolate vs. European Chocolate
Mittleman notes in the news release that differences in the quality of chocolate may have implications for Americans.
In Sweden, even milk chocolate has a higher concentration of cocoa than dark chocolate sold in the U.S. Higher cocoa content has been associated with greater heart benefits.
Researchers say that though 90% of all chocolate eaten in Sweden during the study period was milk chocolate, it contained about 30% cocoa solids.
In the U.S., chocolate that has only 15% cocoa solids can be classified as dark chocolate.
The authors say people in the U.S., therefore, may have fewer health benefits and more calories per equivalent amounts of cocoa content compared to the chocolate eaten by the Swedish women in the study.
In addition, the average size of a serving for Swedish women ranged from 19 grams among those 62 and older to 30 grams among participants 61 and younger. In the U.S., however, the standard portion size is 20 grams.
Watch Your Portions
"Those tempted to use these data as their rationale for eating large amounts of chocolate or engaging in more frequent chocolate consumption are not interpreting this study appropriately," says Linda Van Horn, PhD, RD, professor of preventive medicine at Northwestern University's Feinberg School of Medicine.
"This is not an 'eat all you want' take-home message," says Van Horn, former chair of the American Heart Associations nutrition committee. "Rather, it's that eating a little dark chocolate can be healthful, as long as other adverse behaviors do not occur, such as weight gain or excessive intake of non-nutrient dense 'empty' calories."
About 1% of Americans over 65 experience heart failure, a condition in which the heart is unable to pump enough blood to the rest of the body. Rates of heart failure, the news release says, are increasing as the population of the U.S. ages.
The researchers say more study is needed to confirm their findings, because, as Mittleman says in the news release, "anything that helps to decrease heart failure is an important issue worth examining."