By Hara Estroff Marano, published on March 15, 2011 - last reviewed on October 30, 2012
The cocoa bean formally belongs to the genus Theobroma, or food of the gods. Not many mortals would disagree. And science now rewards their taste. Researchers are finding that consumption of cocoa-rich chocolate, loaded with classy antioxidants, offers a growing array of benefits to brain and body. Most surprising is that, when processed to preserve its fullest complement of natural antioxidants, cocoa may have therapeutic benefits against cardiovascular ills that take a special toll on the aging brain.
Native to South America, the bean of Theobroma cacao was ground and consumed as a warm beverage 2,000 years ago by Mayans and, later, by the Aztecs, who called it "bitter water." Columbus was the first European to sample the beverage, often spiced with pepper, but it was only after Cortés conquered the Aztecs that it became a prized drink in Spain, despite the fact that the hot and spicy drink was considered morally dangerous. Mixing it with milk and sugar made it more palatable to Europeans.
Long before chocolate was transformed into a dessert, it was valued for promoting health. Cortés wrote to King Carlos I of Spain that he had found a "drink that builds up resistance and fights fatigue," and brought tons of beans back with him. When Thomas Jefferson got his first sip in France, he wrote John Adams: "The superiority of chocolate, both for health and nourishment, will soon give it the same preference over tea and coffee in America which it has in Spain." European doctors recommended cacao for angina, respiratory problems, dysentery, indigestion, weakness, gout, liver and kidney disease, and general revitalization.
Cacao begins its transcendence into chocolate with fermentation after harvesting. The large, rugby-ball-shaped fruit of Theobroma contain about 40 cocoa beans embedded in a sticky, white pulp. The beans are scooped out and placed in trays for open-air fermentation, during which the pulp sugars alter the chemical composition of the bitter beans. Then the beans are dried, typically outdoors. An average tree produces 30 viable pods a year—yielding two pounds of chocolate.
Shipped off to factories, the dried beans undergo roasting for flavor development— at high temperatures for a short time, which boosts chocolate flavor, or lower temperatures for a longer time, believed to preserve more subtle flavors and more of the antioxidants. Then they are ground.
The resulting chocolate liquor may—with the variable addition of sugar, vanilla, and powdered milk—head straight for molding into chocolate bars or undergo pressing to separate the fatty cocoa butter from the cocoa solids, which are pulverized into cocoa powder. The cocoa butter—about a third of which is oleic acid, the same fat found in olive oil—is typically mixed back into chocolate as it later undergoes kneading and hot-and-cold tempering to further develop flavor and impart gloss. Cocoa butter also contains saturated fats, primarily stearic acid, which does not raise cholesterol levels.
During processing, cocoa beans may be washed to neutralize acids and decrease bitterness. Such so-called Dutch processing darkens the cocoa but halves its naturally high antioxidant level.
Cocoa and cocoa-laden dark chocolate have been identified as rich sources of antioxidants known as flavanols. Cocoa has more cardioprotective proanthocyanidins than blueberries, more brain-saving catechins than green tea, more heart-healthy phenols than red wine. Two tablespoons of cocoa have more antioxidants than four cups of green tea.
For over two decades, chocolate has been linked to protecting the cardiovascular system, and especially to lowering blood pressure, shielding the brain from stroke and the heart from overwork.
Researchers at Johns Hopkins have shown that a few squares of chocolate—the equivalent of two tablespoons of dark cocoa—can halve the risk of heart attack by decreasing the tendency of blood platelets to clot. The effect is similar to that of aspirin. Italian investigators have found that a small square of chocolate two or three times a week reduces levels of C-reactive protein, an inflammatory substance that is a risk factor for heart attack and stroke.
In a German study, a mere 30 calories worth of dark chocolate significantly lowered both systolic and diastolic blood pressure in middle-age and older men and women—without adding weight. Prevalence of hypertension dropped from 86 to 68 percent over 18 weeks of chocolate-eating, which, by boosting flavanols in blood, stimulated production of arterial nitric oxide, a compound known to relax blood vessels and increase blood flow through them (it's the source of Viagra's power). Swedish researchers have found that dark chocolate also biochemically mimics the first-choice drugs for hypertension by inhibiting the ACE enzyme known to raise blood pressure.
A German study that followed nearly 20,000 men and women age 35 to 65 for 10 years observed a 39 percent decrease in risk of stroke and heart attack among those who ate a small square of chocolate daily. Canadian researchers determined that eating 50 grams of dark chocolate a week markedly reduces the risk of death in those who have already suffered a stroke. What's more, chocolate seems to protect against heart failure and to lower the risk of death among those already diagnosed with the condition.
By increasing blood flow to the brain, chocolate also significantly protects against cognitive decline among those over 60, a separate study found. And Oxford University researchers who tested older chocolate eaters confirmed that they perform significantly better on a range of cognitive tests than those who do not partake.
But chocolate's benefits are not limited to any age group. "If you're going to have a treat," says Murray Mittelman, who directs a cardiovascular research unit at Harvard, "dark chocolate is probably a good choice, as long as it's in moderation."
What makes chocolate so appealing to you and me is what excites scientists about the health value of chocolate: People don't have to retrain habits to partake of the merits. They just have to make sure to buy a cocoa-rich version, but not too much. A square of dark chocolate a day will do it. More promotes weight gain, which offsets cardiovascular benefits. And the milk in milk chocolate interferes with antioxidant absorption.
The finest cocoa beans come from the tropics of Madagascar and the Americas, but Africa is the bulk producer; the single largest supplier of cocoa is the Ivory Coast.
Look for a product with the highest cocoa content (above 70 percent) and the fewest other ingredients. The best chocolate, says Jacques Torres, renowned New York chocolatier, contains only cocoa, sugar, cocoa butter, and lecithin, an emulsifier.