Dark Chocolate’s Heart Advantages
Evidence is building that products of the cacao plant, especially dark chocolate, are good for your heart. Studies show that people who eat dark chocolate have healthier cardiovascular systems, including better blood circulation, lower blood pressure, and lower cholesterol levels. Cardiologist and Everyday Health columnist T. Jared Bunch, MD, who directs heart rhythm research at the Intermountain Medical Center Heart Institute in Murray, Utah, recommends eating chocolate as part of a strategy to keep heart disease — the world’s No. 1 killer — at bay. “Dark chocolate should be part of a life plan that includes eating healthy foods that are largely plant-based, getting regular exercise and adequate sleep, reducing stress, and maintaining a [healthy] weight,” says Dr. Bunch. Here, we explore the science behind dark chocolate’s benefits for the heart.
Cacao Is Linked to Heart Disease Prevention
Early signs that cacao is a heart-healthy food came from the unusually healthy elders of the island population of Kuna Indians in Panama, who drank large amounts of unprocessed cacao — about four cups a day — and were free of heart disease, according to a study in the Journal of Cardiovascular Pharmacology. When they moved to cities, adopted Western ways, and gave up traditional cacao drinks, the Kuna developed high blood pressure in old age like the rest of us. Many studies, including 20 on cacao’s effects on blood pressure alone, show links between chocolate and markers of good heart health. Caution with cacao is advised if you’re prone to bad headaches, as chocolate may trigger migraines. And people with chocolate allergies should not eat any type of cacao product, including raw cacao, cacao nibs or powder, dark chocolate, and milk chocolate.
Chocolate’s Secret Power for Heart and Blood Vessel Cells
Seeds of the Theobroma cacao plant, the source of dark chocolate, are rich in active compounds known as antioxidants. Dark chocolate is one of the top 10 dietary sources of antioxidants, along with seasonings like cloves, mint, anise, cacao powder, and berries like black chokeberry and black elderberry, according to the European Journal of Clinical Nutrition. Dark chocolate is also rich in bioactive flavanols and theobromine, which have positive effects on cells of the heart and blood vessels, according to researchers at the University of Mississippi. But there’s a caveat if you’re watching your fat intake: One ounce (oz) of dark chocolate, though low in cholesterol at only 2 milligrams (mg), has about 9 grams (g) of fat. “In general, the health benefits outweigh the risk of the additional calories,” says Bunch. “When you consume dark chocolate that’s more than 70 to 80 percent pure, the calories are relatively low,” he adds. In less-concentrated forms of chocolate — such as white or milk chocolate — other ingredients add lots of calories with no proven heart benefits.
Dark Chocolate Can Boost Blood Circulation
More evidence of the health benefits of dark chocolate comes from a 2014 Italian study in the Journal of the American Heart Association, which showed that eating dark chocolate helped people who have peripheral artery disease (PAD) walk farther and longer. PAD decreases blood flow to the arms and legs, so patients often have painful cramping and difficulty with exercise, even while walking. People with PAD in the study who ate 40 g (1.5 oz) of dark chocolate a day were able to walk 11 percent farther, and 15 percent longer, than people who ate the same amount of milk chocolate. The dark chocolate used in the study contained more than 85 percent cacao and was rich in active compounds known as polyphenols. Researchers looked at markers of oxidative stress in the blood and found improvement in those who ate dark chocolate.
Cocoa Calms Blood Pressure
If your blood pressure has continued to climb over the years, there’s some good news for you: Eating dark chocolate is also linked to significantly lower blood pressure, according to an extensive analysis of 20 randomized controlled trials published as a Cochrane Review. Most of the studies were short-term, but even one 18-week trial showed a significant drop in blood pressure. In that study, people ate about 6 g (1/4 of an oz) of dark chocolate daily. Researchers compared this group with those who ate the same amount of white chocolate, and dark chocolate was the clear winner. Systolic blood pressure (the top number) in people who ate dark chocolate went down by three points, while diastolic blood pressure (the bottom number) went down by two points. If you’re tracking yours, keep in mind that an ideal blood pressure is less than 120/80, according to the American Heart Association.
Dark Chocolate May Lower Stroke Risk
Finnish researchers found that eating chocolate also reduces the risk of stroke, a major health concern for many — especially those with atrial fibrillation (afib). Stroke risk is five times higher in people with afib than in those who don’t have afib, according to the National Stroke Association. And stroke, which occurs when a blood clot forms in the brain or a blood vessel bursts, is a leading cause of disability in the United States.
The Finnish researchers followed a group of more than 37,000 men for 10 years, counting instances of stroke. Those who ate about 63 g (2 oz) of chocolate per week had a lower risk of stroke, compared with those who ate no chocolate. And five additional studies showed chocolate eaters had about a 20 percent average lower stroke risk than those who didn’t eat chocolate. “Dark chocolate helps reduce blood pressure and may have a role in coronary artery disease stability and diabetes,” says Bunch. “So dark chocolate may help lower stroke risk.” But Bunch warns that you shouldn’t replace prescription blood thinners or anticoagulants — the only treatments proven to prevent stroke — with chocolate.
Dark Chocolate Relieves Stress on Your Heart
An often overlooked, but very real risk factor for heart disease, is stress. You’ll be happy to know that the solace provided by dark chocolate is not limited to its good taste: A June 2014 study found that eating dark chocolate helped people cope with stressful situations. Researchers measured the stress hormones cortisol and epinephrine, and then challenged people to do things like figure out a difficult math problem in their heads. Those who ate dark chocolate reported feeling less stress, and indeed had lower levels of stress hormones circulating in their blood following the stress test. Blunting the effects of stress on the body is yet another way dark chocolate can protect heart health, which is good news even for people with a heart condition. “Dark chocolate has been shown to favorably impact some of the risk factors for atrial fibrillation, such as high blood pressure, body inflammation, and the response of the body to stress,” says Bunch.