Chocolate and Your Health: Guilty Pleasure or Terrific Treat?

It's an old story, very old, in fact. Forbidden fruits taste the best. The apple in Eden may have started it all, but there are many modern equivalents, ranging from juicy burgers and crispy fries to salty snacks and fine cigars. But science and experience can also move things from column A to column B. Far from being a guilty pleasure, alcohol, for example, can actually promote health if the dose is right (low) and the drinker is responsible. The same is true for nuts. On the other side of the coin, many people who think of exercise as a painful duty actually can come to experience it as pleasurable.

What about chocolate? Does it deserve its bad rap, or is it the latest thing in health foods? As for many complex questions, the answer is both, since the consequences of eating chocolate depend largely on the type of chocolate and the amount you consume.

A taste of history

It all begins with the cacao tree, which originated in Central America more than 4,000 years ago and has been cultivated by humans for more than 1,000 years. The Aztecs and the Mayans were fond of the tree, believing that the seeds were a divine gift from paradise. Both groups used the cacao in religion and commerce; as currency, 100 beans had the value of one slave.

Chocolate was among the earliest American exports. Cortéz brought cacao beans to Spain in the early 16th century. The Spaniards added sugar and cinnamon to the bitter Indian drink, and the rest is history. The cacao tree is now grown in equatorial regions of Africa and Asia as well as in the Americas, which still produce some of the world's cacao beans.

Beans to bars

Chocolate doesn't grow on trees, but cacao beans do. After harvesting, the beans are dried for several days and then roasted. Next, the beans are opened, the shells are discarded, and the nibs are ground and separated into cocoa butter and cocoa powder. The powder is low in fat and is used for baking or to make hot chocolate, while the cocoa butter is the heart of the chocolate we eat.

Cocoa butter is dark and rich, but it tends to be bitter. To increase its appeal, confectioners process it further. One popular method is called Dutch processing; it makes the color lighter, but it also removes many of the ingredients that appear beneficial. To make chocolate sweeter, manufacturers add sugar, which also adds calories. And to make milk chocolate, candy makers really do add milk solids, which include saturated fats. According to FDA standards, American milk chocolate can contain as little as 10% cocoa, and the agency is debating a proposal to allow candy makers to substitute vegetable oil for cocoa butter. Bottom line: processing may make chocolate look lighter and taste sweeter, but it also removes healthy ingredients and adds harmful ones.

A bite of chemistry

The cacao bean is devilishly complex, containing more than 400 chemicals. Many of them can affect human biology and health.

Fats. Cocoa butter is high in fat. It's what gives chocolate its tempting texture and "mouth feel" — but it's also what gives chocolate its bad name. Although it's true that the fat packs in a lot of calories, it's not guilty of the charge that it boosts blood cholesterol levels.

About a third of the fat in cocoa butter is oleic acid, the very same monounsaturated fat that gives olive oil its good name. Another third is stearic acid; it is a saturated fat, but unlike the three other saturated fats in the human diet, stearic acid does not raise cholesterol levels because the body can metabolize it to oleic acid. And while chocolate also contains some palmitic acid, a saturated fat that does boost cholesterol, careful studies show that eating chocolate does not raise blood cholesterol levels.

Flavonoids. The humble cacao bean contains a number of chemicals in the flavonoid family. Polyphenols protect chocolate from turning rancid, even without refrigeration. Even more important are the flavanols, a group of chemicals that are responsible for many of the protective actions of chocolate. Flavanols are present in many healthful foods — but dark chocolate is the richest source (see table).

Amino acids. Chocolate is high in tryptophan, phenylalanine, and tyrosine. Like other amino acids, these nitrogen-rich compounds are the building blocks of all the body's proteins. But two of these amino acids have a unique property: they are precursors of adrenaline, a "stress hormone," and dopamine, a neurotransmitter that relays signals between nerve cells in the brain. Scientists postulate that dopamine induces feelings of pleasure; if so, the passionate craving of the true chocoholic may have a neurochemical basis. But these chemicals may also explain some of the adverse effects of chocolate, including its ability to trigger headaches in some migraine sufferers, its ability to raise blood pressure to dangerous levels in some patients taking monoamine oxidase inhibitors for depression, and its ability to instigate diarrhea, wheezing, and flushing in patients with carcinoid tumors, which are rare.

Methylxanthine. Chocolate contains two members of this group of chemicals. One is obscure, the other notorious — but both theobromine and caffeine have similar effects on the body. They may explain why chocolate makes some hearts beat faster — and why it gives many people heartburn by relaxing the muscle between the stomach and the esophagus, thus allowing acid to reflux up from the stomach into the sensitive "food pipe."