Chocolate’s Sensuous Mysteries
Chocolate. Since the reign of the Mayas, this so-called food of the gods has exerted a bewitching--some would say addicting--pull on mortals.
Montezuma drank golden goblets full of a blood-colored concoction of chocolate and chilies before taking to his harem, believing it an aphrodisiac. For centuries in Europe, hot chocolate tonics soothed most known ailments.
Today, scientists are sifting through chocolate’s ingredients, trying to understand its allure and its effect on the heart and brain.
First, the deliciously counterintuitive good news: Studies to be presented at a scientific meeting this week--as Americans indulge in $1-billion worth of Valentine’s Day goodies--show that the fatty substance is chock-full of antioxidants that might prevent heart disease.
But many nutritionists and public health experts see a darker side. They allege that a few far-from-conclusive studies, funded in part by chocolate manufacturers, are being promoted in a bid to whitewash chocolate’s decadent image.
They’re suspicious of the recent placement by one candy maker of “updates” itemizing chocolate’s putative health benefits in the Journal of the American Dietetic Assn., which reaches most of the nation’s professional nutritionists.
“Chocolate is extremely tasty--I just ate a chocolate chip cookie--but there’s no way it helps people,” said William Connor, a clinical nutritionist at Oregon Health Sciences University.
Other studies are overturning many myths about the confection that have persisted since the cacao bean was first harvested, ground and eaten by Mayas and Aztecs. Many of those myths swirl around the confection’s supposed relationship with sex.
Despite Montezuma’s ardent belief, and the 35 million heart-shaped boxes of chocolate sold this week, there is no evidence that chocolate is an aphrodisiac. (Though it might give a weary emperor energy and a quick pick-me-up.) And there is no serious science to support the idea that women prefer chocolate to sex or that eating chocolate sends the brain a surge of amphetamine-like chemicals that mimic the insanity of infatuation.
“I have not found evidence of that ever, ever, ever,” said Adam Drewnowski, an expert on taste who directs the nutrition program at the University of Washington.
That myth was fueled by the discovery in chocolate of trace amounts of phenylethalamine, a chemical produced in the brains of people in love. The truth is, you’d get more phenylethalamine from a salami sandwich.
“But the salami sandwich is not the gift of love in our culture,” said Marcia Pelchat, a psychologist at the Monell Chemical Senses Center in Philadelphia.
In studies, women are more likely to crave sweet things than men, who prefer salt and meat. For some women, cravings peak as their menstrual periods begin and evaporate after menopause, suggesting that hormones spawn chocolate urges.
Urges that chocolate lovers say are very real. “I can’t imagine life without it,” said Netty Worsencroft, a self-described chocolate lover who runs a Web site called the Chocolate Lovers Haven (https://website.lineone.net/~jwor sencroft). “The word share? What’s that?”
Cravings Are Real Phenomenon
While nutritionists agree that such chocolate cravings are a real phenomenon, Pelchat’s studies show that they are not based on any bodily need. People given an adequate but boring liquid diet of a sweetly flavored nutritional beverage, she found, craved only salty foods--suggesting that variety is key.
Though chocolate is rich in trace minerals such as copper, there is scant evidence that people seek it to replenish deficiencies. And it is also unlikely to ease depression by boosting serotonin levels, say chemists.
In another study, by University of Pennsylvania psychologist Paul Rozin, chocolate addicts weren’t sated by capsules of cocoa powder full of chocolate’s active ingredients. Instead, they preferred chocolate bars--even white chocolate bars, sticks of fat and sugar that contain no chocolate at all.
The evidence supports Rozin’s theory that chocolate’s appeal lies largely in its texture. Cocoa butter in chocolate is blessed with a magical melting point that dissolves precisely at mouth temperature. It literally melts in your mouth. “There’s really nothing magical in chocolate but sugar and fat--but what fat it is,” says Drewnowski.
In 1995, Drewnowski discovered something that any chocolate lover knows: The stuff causes intense pleasure. When he gave volunteers a short-term drug to block the brain’s pleasure sensors--opiate receptors--subjects ate less chocolate, but chowed through pretzels and popcorn. Chocolate may not provide pleasurable chemicals, but it does stimulate the brain to release its own natural relaxants and painkillers, he said, adding that the sugar, fat and texture of chocolate may be enough to trigger that release.
But Daniele Piomelli, a pharmacologist at UC Irvine, argues that there’s more to chocolate than texture. Texture and sugar, he said, don’t explain why early Central Americans relished bitter, liquid chocolate that most modern-day chocoholics would abhor.
In 1996, Piomelli made headlines with a study showing that chocolate contains cannabinoids, the active ingredients in marijuana. The finding, he said, immediately drew representatives of the chocolate industry to visit his lab and criticize his results.
“A huge amount of paranoia and misinterpretation went into looking at my results,” said Piomelli, who as a result quit studying chocolate as a potential for new painkillers and antidepressants. “There are some big interests out there that make it very hard to unmask these properties.”
A study last year--funded by Nestle--showed that there are not enough cannabinoids in chocolate to trigger any drug-like response, except by eating a 22,000-pound candy bar.
Piomelli said he never suggested that chocolate’s cannabinoids could cause a high, but he said they could prevent the body from breaking down its own natural marijuana-like compounds. With those lingering in the brain, a person could feel pleasure, he said.
Risks May Be Overstated
Is there anything physiological to chocolate’s pull? “Definitely,” says chocoholic Jill Pace, executive director of the American College of Real Estate Lawyers. The large luncheons that she organizes provide ample evidence.
“If you serve a nice, simple fruit tart for dessert, at the end of the meal, they’re all left over,” she said. “But when you serve something chocolaty, those plates are empty.”
For chocolate lovers, she added, any health risks are small and well worth it. But those risks now may be smaller than suspected.
Studies show that chocolate’s antioxidant content compares favorably with those of red wine, green tea and some fruits and vegetables, said Joe Vinson, a chemist and expert on antioxidants at the University of Scranton in Pennsylvania. Antioxidants in chocolate may also be more effective than those found in other foods, he said.
This foray into chocolate chemistry started with a quiet attempt at Mars Inc. laboratories to understand the secret of chocolate’s flavor. The work required seven or eight years’ worth of precise chemical analyses.
“Brutal would be an apt word for it,” said Harold H. Schmitz, a Mars food scientist who manages the lab at Hackettstown, N.J., where the work was conducted. The search paid off in the early 1990s with the discovery of a diverse array of antioxidants within chocolate. The finding came just as nutritionists began advocating red wine as a natural source of antioxidants.
To investigate potential health benefits, Mars scientists enlisted the help of nutritionists at UC Davis. There, nutritionist Carl L. Keen confirmed that components in chocolate could prevent the oxidation of cholesterol--a key step in clogging arteries--and that antioxidants did enter the bloodstream where they could do some good.
Though he’s had to get past the “chuckle factor” of colleagues, Keen says he’s convinced that chocolate will emerge with newfound nutritional respect. “If you had asked someone five years ago if there would be a label on wine suggesting health benefits, people would say ‘You’re crazy,’ ” he said.
Studies conducted by nutritionist Penny Kris-Etherton of Pennsylvania State University over the past decade show that a main contributor of the saturated fat in chocolate--stearic acid--does not raise cholesterol levels. A surprising new finding shows that chocolate eaters had higher amounts of so-called good cholesterol than pretzel eaters.
While chocolate looks good in a test tube, skeptics say there’s no proof that lab tests translate into lowered heart disease risk. “It’s just a theoretical argument at this point,” said Frank B. Hu, a dietary fat expert at the Harvard School of Public Health who said stearic acid may boost harmful blood clotting factors.
Another study published last year showed that candy eaters lived on average of one year longer than those who didn’t indulge. Though the study wasn’t taken as a serious result by health experts, it did gain widespread coverage in the news media.
Some public health experts argue that such borderline research findings are being overplayed by the chocolate industry--through news conferences and Web sites--in an attempt to improve chocolate’s image among nutritionists.
At news conferences staged during scientific meetings, including one this week at the American Assn. for the Advancement of Science in Washington, D.C., findings on chocolate are often lapped up by the media as eagerly as the free candy samples that often accompany them.
All major studies of chocolate have been funded by Mars or a chocolate lobbying group, the Chocolate Manufacturers Assn. No one considers the science suspect; Schmitz and Mars get high ratings for the quality of their science. Keen, Kris-Etherton and Vinson all have stellar reputations in their fields and publish their work in respected, peer-reviewed journals.
Many university researchers say funding of nutrition research by the food industry is unfortunate but necessary, because neutral agencies like the National Institutes of Health do not adequately fund their work. Kris-Etherton said she maintains a vigilant stand against any conflict of interest.
This month, Mars paid the American Dietetic Assn. to include several pages of “Chocolate Updates” in its prestigious journal--something that food watchdog Michael Jacobson of the Washington-based Center for Science in the Public Interest calls “a full-fledged PR effort to go after the general public and go after nutritionists.”
An ADA spokeswoman said the group receives less than 10% of its funding from the food industry, and uses the money to publish only nutritionally sound messages.
Directors of the Chocolate Manufacturers Assn. say their job is to promote and encourage the eating of chocolate and they will do so, but only within reason. “We certainly are not suggesting that chocolate should replace fruits and vegetables in your diet,” said Susan Fussell, a spokeswoman.
One Japanese chocolate manufacturer, Meiji, is promoting chocolate as healthful: It offers a chocolate fortified with extra antioxidants. More disturbing to some nutritionists is the chocolate lobby’s petition to the Food and Drug Administration to reclassify stearic acid as less harmful than other saturated fats. That divisive issue is pending.
For now, the controversies surrounding chocolate show no sign of melting away. Any resolution will take dozens of new studies, including clinical trials that induce hundreds of people to eat more chocolate. Not surprisingly, says Keen, there’s no shortage of volunteers.
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Pharmaceutically Active Components in Chocolate
These chemical compounds have been detected in chocolate. Whether they exert biological effects remains a matter of dispute.
Serotonin--a neurotransmitter that plays a role in regulating mood and is affected by the commonly used antidepressant Prozac. While found in chocolate, it is found in much higher amounts in other carbohydrates.
Caffeine--a stimulant, found in chocolate in very small amounts.
Theobromine--a caffeine-like stimulant, found in chocolate in higher amounts.
Phenylethylamine--an amphetamine-like substance also found in the brains of people who are in love. While found in chocolate, it is found in much higher amounts in meats such as salami.
Polyphenols--antioxidants, also found in red wine and green tea, that may prevent heart disease by preventing the clogging of arteries and improving cholesterol levels.
Cannabinoids--these chemicals, the active ingredients in marijuana, are found in chocolate in very small amounts. They may influence the brain’s production of painkilling compounds.
