After working below the radar on a cocoa farm deep in Brazil, and toiling for years over test tubes in food labs, scientists say they have developed a top-secret formula for an undisciplined candy lover's dream: a healthful chocolate bar.
Eating a couple of tiny slabs a day of this dark chocolate could lower cholesterol, relax your blood vessels and help ward off heart disease, they say.
Loaded with potent chemicals such as cocoa flavanols, plant sterols and soy -- and stamped with an icon that reads, "promotes a healthy heart" -- the CocoaVia line of chocolates has been available in select locations since October 2005. By April they'll be in mainstream grocery stores.
Don't look for these bars in the candy section: Possibly the first chocolates explicitly marketed as health foods, they will be over in the health aisle.
Mars Inc., which makes CocoaVia, says this is only the beginning. "There is a next generation of products in the pipeline," said Harold Schmitz, chief scientist for Mars.
"We are investigating dozens and dozens of product formats," he added.
But some nutritionists roll their eyes at the notion that eating chocolate -- even if it is made with a special patented recipe and supplemented with healthful ingredients -- is the best way to promote cardiovascular health.
"If someone is addicted to chocolate, this may be a better choice than other chocolate bars," said Mark Kantor, associate professor of nutrition at the University of Maryland.
"But to think that you are going to lower blood cholesterol levels, or chance of heart disease, by eating two of these a day, that is just wishful thinking."
CocoaVia chocolate bars are made from a patented powder known as Cocoapro cocoa. Cocoa in its raw state is one of the best known sources of plant flavanols: a naturally occurring compound in plants found to a lesser extent in red wine, green tea and certain vegetables.
Cocoapro, Schmitz says, is a flavanol powerhouse, manufactured to be of consistently high quality, often containing many times more than other, run-of-the-mill cocoas.
A growing body of evidence suggests that these flavanols found in cocoa are good for you.
In the early '90s, Harvard University Professor Dr. Norman Hollenberg (who later collaborated with Mars on cocoa research) found that a population of island-dwelling Kuna Indians of Panama, who consume three to four cups of cocoa a day, had lower blood pressure, less hypertension and fewer cardiovascular diseases than their relatives who moved to the mainland and dropped their cocoa consumption.
And earlier this month, Dutch researchers reported in the Archives of Internal Medicine that older men who consumed a lot of cocoa had a 50 percent lower risk of dying from any disease than those who ate none over the course of the 15-year study.
A review of 136 scientific articles on chocolate and its ingredients published between 1996 and 2005 found that eating small amounts of dark chocolate reduces the risk of dying of heart disease by about 19 percent, according to an analysis that appeared January in the journal Nutrition and Metabolism.
One hundred milligrams of flavanols daily appear to have beneficial effects, such as lowering blood pressure and improving insulin sensitivity, said Eric Ding, a graduate student at the Harvard School of Public Health who conducted the analysis.
But, he added, "no one has done any long-term, randomized trials" -- carefully controlled experiments in which people are given flavanol-rich chocolate, or not, and had their heart health tracked over years.
No food company is ever likely to perform such a pricey and time-intensive study on chocolate, scientists say.
But what about the calories?
CocoaVia bars cost a little more than a dollar each and are a little larger than a single Twix bar. They contain between 90 and 100 calories and no trans fats.
Each contains more than 100 milligrams of flavanols: Eat two a day, advises the company, and you will get enough to promote heart health.
The bars also contain between 1.1 and 1.5 grams each of plant sterols, cholesterol-like substances made by plants. Studies suggest that eating 2 grams of plant sterols a day lowers cholesterol by 10 percent, and companies are permitted to make a health claim that their product reduces cholesterol if it contains 1.3 grams of plant sterol esters per serving.
These ingredients don't sway some nutritionists.
"One can only be in awe of the creativity of chocolate marketers," said Marion Nestle, professor of nutrition, food studies and public health at New York University, in an e-mail. "My take is that if there is a health benefit, it is small."
CocoaVia chocolates, though not as calorie-laden as some candy bars, are not calorie-free. Without trimming 200 calories somewhere else, or walking an additional 45 minutes each day, one could end up gaining 20 pounds over a year, wrote Harvard nutritionists in a February article about CocoaVia.
"If somebody decides to consume plant sterols because they have elevated cholesterol levels, it might be better to try to find a non-caloric source," said Alice Lichtenstein, who heads the American Heart Association's nutrition committee.
Mars has spent years isolating flavanols and refining the CocoaVia recipe. It has funded and collaborated with academic researchers on numerous chocolate studies, published in half a dozen or more peer-reviewed journals.
Roger Clemens, a professor at the University of Southern California School of Pharmacy and spokesman for the Institute of Food Technology, called the cocoa work "fascinating."
"Mars has made the effort and spent the money to actually do the clinical studies to see if it works," he said. "I think that is the approach food companies must take to substantiate their position as more health foods enter this market called 'functional foods.' "