This lesson is presented as an overview of what it"s known and the industry wants you to know about choco-late. Read on at your own risk.
It was a hunch, little more, that launched Daniele Piomelli and his coworkers on their search for marijuana like compounds in chocolate. But their intuition paid off. These neuropharmacologists not only found one such cannabinoid, but perhaps more importantly, they also turned up two related chemicals that they believe could provide therapeutic insights into treating a host of ails, including depression.
Chocolate is one of the world's most widespread passions. The typical Swiss eats more than 21 pounds of this candy each year. Even the average Belgian or Brit downs some 16 pounds annually, and here in the United States, consumption weighs in at roughly 11.5 pounds per year.
Not only is this "the food most commonly craved by women," observes Adam Drewnowski, director of the University of Michigan's Human Nutrition Program, but owing to its hedonistic properties, chocolate can play a major role in a number of disorders, including bulimia, binge eating, and obesity.
In susceptible individuals, for instance, it can fuel an addiction-like desire, especially among people who exercise excessively, such as dancers. Drewnowski found that among ballerinas, "chocolate is a fetish food." They crave it, talk about it endlessly — even dream about it.
There is some hints that chocolate may possess natural analgesic properties, Drewnowski says. His own studies indicate that eating high fat, chocolate foods can trigger the brain's production of natural opiates or endorphins.
Last year, Drewnowski showed that when he used a drug to block the brain's opiate receptors, a binge-eater's desire for sweet, fatty foods — such as chocolate — plummeted. One major unanswered question remained: Does the body simply desire anything sweet and fatty, or does it instead feel some special craving for chocolate? In fact, all of the sweet, fatty foods used in Drewnowski's taste trials contained at least some chocolate.
In the Aug. 22 Nature, Piomelli's group identifies a trio of compounds in chocolate that may act independently of fat and sugar — at least in their ability to enhance a sense of pleasure or well-being.
Two years ago, Piomelli and some European colleagues reported the first evidence that nerve cells in the brain produce anandamide. This chemical activates the same cellular receptors as THC, the agent in mariju-ana smoke that causes a pleasurable "high". Shortly after the brain makes anandamide, an enzyme breaks it down. The system naturally limits anandamide lifespan, and, thereby, the duration of this cannabinoid's ef-fects.
Unfortunately, Piomelli admits, "We really don't know what anandamide does in the brain. But we can draw deductions from the effects of THC because when we give anandamide to animals, it produces the same effects as when you inject them with THC."
In the recent study, Piomelli's group identified two anandamide-like compounds in chocolate — which go by the unwieldy names of N¬oleoy¬lethanolamine and N-linoleoylethanolamine. At least in test-tube experiments, both delay anandamide breakdown. Moreover, relative to the concentration of anandamide measured in chocolate, those of its chemical cousins proved relatively high.
What made Piomelli look for these compounds? "From a pharmacological standpoint, chocolate is terra incognita" — largely uncharted territory. "But we knew that chocolate contains a lot of fat, and that there are not many fatty substances that modulate brain activity." Because THC was among the few fat-soluble substances with that ability, Piomelli decided to look for its natural analog.
The big surprise, Piomelli says, was the realization that any pleasure we derive from eating chocolate proba-bly traces less to the candy's anandamide than to its chemical cousins — and the role they play in prolonging the pleasurable sensations associated with the body's own natural production of anandamide.
Indeed, such an indirect role in pleasure enhancement would go a long way toward explaining why eating chocolate does not create the same giddy euphoria that smoking marijuana does. "If one smokes a joint, its THC goes into the brain and activates all of the [cannabinoid] receptors," Piomelli explains. "So you get a global high." Because anandamide chemical cousins do not bind to cannabinoid receptors, they may do nothing — unless anandamide is present. Even then, their effects would be limited to just those regions of the brain where anandamide had been naturally produced.
So all that these cousins may be doing is prolonging the natural and quite localized effects of the body's own anandamide, whatever they turn out to be.
Chocolate Kama Sutra or the Confluence of Instincts
Because opiates and cannabinoids trigger different receptors in the brain, Drewnowski points out that any cannabinoid-system effects should occur independently of the opiate responses he has linked to sweetened fats. After all, he notes, if cannabinoids explained the whole picture, unsweetened cocoa powder should be as enticing as a chocolate bar. Then again, he notes that there can be a certain amount of "cross talk" be-tween brain-signaling agents. What this means, he says, is that compounds can sometimes indirectly influ-ence opiates and other systems in unexplained ways — Notwithstanding, Piomelli finds the new cannabinoid data "therapeutically interesting."
Pot smoking often triggers a case of "the munchies" — a sudden appetite. "If you're anorexic because you don't have an appetite, and a drug suddenly makes your food taste better [as THC does], that can be very good," Piomelli maintains. Alternatively, if someone is depressed, a drug that induces a sense of well being can prove beneficial.
"People already self-prescribe chocolate for depression," Piomelli notes. "But presumably, one can come up with something more potent than these compounds in chocolate," he says. Though it would not taste as good as chocolate, he notes that "there's no reason we can't involve it in chocolate." For instance, he posits, "We could put chocolate around it."
In the mean time, individuals wishing to self-medicate with non¬pre¬scription-strength chocolate should reach for cocoa — or dark chocolate, which can contain two to three times as much of these compounds, per ounce, as milk chocolate.
Chocoholics already know this, however. When people strongly crave chocolate, Drewnowski's data show, inexpensive, low-quality candy will not do. "They want very high fat, dark chocolate." And this would seem to bridge his findings to Piomelli's, he notes, since the dark chocolate delivers plenty of cannabinoid cousins in a package enriched with natural-opiates-inducing cocoa butter.
In addition, who said chocolate was just junk food?
FEFL says so. The whole research idea is flawed. And to imply that the anorexic lacks an appetite, only confirms that the authors of the study know little or nothing about anorexia.
Now, prepare to listen from the industry itself
Suspected Link between Chocolate, Cannabis May Improve Treatment of Mental Illness
Maybe you should not think about the rich, sensuous, mouth-watering taste of dark, fragrant chocolate while you read this.
However, if you cannot resist, it may be, according to three scientists at the Neurosciences Institute in San Diego that you are craving not just that taste and texture but also a mild alteration in consciousness similar to that produced by cannabinoids, the psychoactive constituents of the cannabis plant, better known as marijuana.
Chocolate, including cocoa powder, contains three compounds from the N-acylethanolamine group of chemicals that may target the endogenous cannabinoid system in the brain. The substances are not present in cocoa butter.
Just as the brain produces its own version of morphine, it also produces anandamide, a version of tetrahy-drocannabinol (THC), the main psychoactive constituent of marijuana. The name comes from the Sanskrit word "ananda," which means "bliss."
In research on rat brains, psychopharmacologist Daniele Piomelli, and colleagues found that although the N-acylethanolamines do not activate brain cannabinoid receptors, they do inhibit the breakdown of anandamide in brain microsomes and intact rat brain cells.
Microsomes are small particles obtained by centrifuging homogenized brain cells, used to test how sub-stances may be metabolized in the brain.
By interfering with the deactivation of anandamide, N-acylethanolamines may prolong its action and thereby produce a heightened sense of well-being, Piomelli speculates.
Although the study has been treated somewhat lightly in the press and according to Piomelli, elicited worried telephone calls from representatives of chocolate producers concerned with their product's image it has a very serious side, he told CNN News.
"What we care most about is the therapeutic potential of this concept, not necessarily the therapeutic use of these compounds. Rather, [it is significant] that you may be able to improve mood by blocking the break-down of anandamide. This is a serious observation. It is not just something cute that we have done so that now we know more about chocolate. The hope is that it may contribute to helping cure mental diseases."
Much is known about the effects of cannabis, one of the world's most popular recreational euphoriants. Sci-entists first suspected there might be a naturally occurring analogue of plant cannabinoids in the mammalian brain when they discovered a cannabinoid receptor in nerve cells in 1988. The discovery of that analogue in pig brains was reported in 1992, and only within the last year has its existence in human brains been con-firmed, according to Piomelli.
Anandamide is a lipid, which is to say anything derived from a fatty acid, and is lipophilic, that is, it has an affinity for other lipids. It is very short acting because it is degraded and inactivated very quickly, Piomelli explained.
"What we did was, we found an enzyme in the brain that breaks down anandamide," said Piomelli. "Clearly the brain needs mechanisms to inactivate neural signaling molecules."
Piomelli believes it is the "nonselective activation of all cannabinoid receptors" when THC is consumed that causes the cannabis "high." The reason that humans do not walk around continually high from their THC analogue is probably related to its highly selective release and rapid breakdown, Piomelli said.
"Very likely anandamide is only produced in certain areas of the brain. At any given time only a particular subset of cannabinoid receptors will be activated (when endogenous anandamide is released). The normal role of anandamide is not to make us high. The normal role is probably to modulate mood, appetite, and pain," among others.
He stressed that the study is not meant to imply that chocolate produces a state approaching that induced by consuming THC. If anandamide breakdown is blocked, its effects will be exaggerated, "but it still will not be like THC" since the area of the brain where anandamide exists is limited, he said.
Piomelli and colleagues are now testing the effects of the chocolate compounds through intraperitoneal in-jections in rats. The compounds easily cross the blood-brain barrier, he notes.
Chocolate, Chocolate Everywhere
Chocolate candy bars, after-dinner mints, brownies, truffles, doughnuts, chocolate milk-if it has chocolate in it, we eat it. Hot, cold, solid, liquid, over ice cream…even over meat?! Yes, a Mexican sauce called "mole" uses unsweetened chocolate in a sauce that is served over meat. It is a versatile flavor, chocolate. Choco-late has been blamed for acne and tooth decay, but research has found that it is innocent of these evils. That must have made lots of people worldwide sigh in relief: the chocolate industry sells five billion dollars worth of chocolate each year in the U.S. alone. The U.S. is only the eighth largest consumer of chocolate. Switzerland, whose citizens eat more than 21 pounds per person each year, leads the world in chocolate consumption.
An Appetite for Chocolate
Why do we crave chocolate? There are times when nothing else tastes as good as chocolate. There are times when you want nothing else. Nothing else will do. There is even a name for someone who craves chocolate: a chocoholic. It is almost an uncontrollable urge.
Some scientists wondered why the average person in the U.S. eats 11 pounds of chocolate each year. They decided to analyze the contents of chocolate to find out how those compounds might affect our brains, and thus our moods. Just as caffeine seems to perk people up, chocolate seems to make us feel happy.
Chocolate contains approximately 380 known chemicals, so it is no wonder it is difficult to figure out why chocolate is such a favorite treat. In addition, who says that it is only one or two things in chocolate that cause us to feel happy? Many of the chemicals in chocolate are found in other foods, yet we don't buy heart-shaped bananas to show that special someone that we care for them. It may be a unique chemical combination that gives chocolate its edge over vanilla, berry, and caramel. Although chocolate has been said to improve mood, it contains saturated fat and sugar, too, as food is not healthy. Moreover, keep chocolate away from Spot! A two-ounce piece of chocolate can be fatal to a dog because it cannot digest one compound in chocolate called theobromine. Chocolate can also make some small children sick for the same reason.
Whatever the true reason for chocolate's popularity, scientists will continue to investigate the sweet myster-ies of cacao. In the meantime, grab a bar for yourself and a box for your Valentine.
Crazy for Chocolate
Why Does One Crave Chocolate?
Chocolate is the No. 1 most craved food, and women are the ones most likely to crave it. Why we crave chocolate is a complex issue.
Our obsession with chocolate could be partially cultural. While men may receive bottles of whiskey as gifts, women often receive chocolates, forming a link between chocolate and love. Chocolate is not a member of any food group and is rarely part of the meat-and-potatoes main course, so it is not a part of our daily rou-tines or responsibilities. Consequently, chocolate symbolizes an escape from the day-to-day drudgery.
Then there is chocolate's creaminess. The cocoa butter in real chocolate gives it a rich texture. Cocoa butter melts in your mouth, providing what has been termed "a moment of ecstasy."
Chocolate also is the perfect mix of sugar and fat to turn on almost every appetite-triggering nerve chemical in the brain. The sugar in chocolate sparks the release of a nerve chemical called serotonin and might lower another nerve chemical called NPY; the end result is a sense of well-being. The sweet taste also releases endorphins in the brain, giving us an immediate euphoric rush. The fat in chocolate enhances flavor and aroma and satisfies another nerve chemical called galanin, thus curbing our cravings for fat.
That's just the tip of the iceberg when it comes to nerve-tingling chemicals. Chocolate contains theobromine and caffeine, compounds that provide a mental boost, and phenylethylamine, or PEA, which stimulates the nervous system, increases blood pressure and heart rate, and is suspected to produce similar feelings experienced when a person is "in love." Even the aroma of chocolate could affect brain chemistry. Finally, chocolate contains a substance called anandamide that mimics the effects of marijuana and boosts the pleasure you get when you eat chocolate.
Not all of these connections between chocolate and body chemistry have been substantiated by well-designed research; consequently, many questions remain. For example, cheese and salami also are sources of PEA but seldom evoke similar cravings. In fact, the amount of PEA in a chocolate bar is not likely to be enough to trigger romantic feelings. The endorphin-chocolate link is based on animal studies; no such studies have been conducted on humans so it is only speculation that people and rats share a similar endor-phin rush when eating chocolate.
In summary
Others argue that a craving for chocolate is really the body's craving for its nutrients, such as magnesium. If this is the case, why don't people crave soybeans, peanuts, and other magnesium-rich foods? In fact, chocolate cravings usually can be satisfied only by chocolate or something that mimics its texture, taste, and aroma. Since cocoa contains more than 400 distinct flavor compounds, it is likely there are yet unexplored compounds that trigger cravings.
In short, no one knows exactly why we love chocolate, yet the cravings are very real. Since chocolate urges are not likely to "just go away," the best tactic is to include a small chocolate snack in your eating plan and enjoy the experience. While you get fat…
Bibliography
• Brain cannabinoids in chocolate E. di Tomaso, M. Beltramo, D. Piomelli, Nature, 382, 677-8 (1996).
• Coming: Drug therapy for chocoholics? Science News, 147, 374 (1996).
• Chocolate may mimic marijuana in brain. Chemical and Engineering News 74, 31 (1996).
• P. Derkinderen, M. Toutant, F. Burgaya, et. al., Science, v. 273 # 5282, Sept 20 1996 pp. 1719-1722
• Z. M. Yan, B. C. Paria, S. K. Dey, Biol. Reprod., 55, 756-761 (1996).
• Anandamide Levels And Cannabinoid Receptors In The Mouse Embryo (KUMC) Studies of anan-damide signaling in early pregnancy.
• Bailleux, Nathalie, et al. The Book of Chocolate. Paris: Flammarion, 1995.
• Beckett, S. T., ed. Industrial Chocolate Manufacture and Use. 3rd edition. Oxford: Blackwell Science, 1999.
• Coe, Sophie D. America's First Cuisines. Austin: University of Texas Press, 1994.
• Coe, Sophie D., and Michael D. Coe. The True History of Chocolate. New York: Thames and Hud-son, 1996.
• Dand, Robin. The International Cocoa Trade. 2nd edition. Cambridge, U.K.: Woodhead Publishing, 1999.
• Dillinger, Teresa L., Patricia Barriga, Sylvia Escárcega, Martha Jimenez, Diana Salazar Lowe, and Louis E. Grivetti. "Food of the Gods: Cure for Humanity? A Cultural History of the Medicinal and Rit-ual Use of Chocolate." Journal of Nutrition 130 (2000): 2057S–2072S.
• Drewnowski, Adam, and Carmen Gomez-Carneros. "Bitter Taste, Phytonutrients, and the Consumer: A Review." American Journal of Clinical Nutrition 72 (2000): 1424–1435.
• Girard, Sylvie. "Les vertus aphrodisiaques du chocolat [The aphrodisiac qualities of chocolate]." Ca-hiers Sexol. Clin. 11 (1985): 60–62.
• Knight, Ian, ed. Chocolate and Cocoa, Health and Nutrition. Oxford: Blackwell Science, 1999.
• Morton, Marcia, and Frederic Morton. Chocolate: An Illustrated History. New York: Crown Publishers, 1986.
• Schivelbusch, Wolfgang. Tastes of Paradise: A Social History of Spices, Stimulants, and Intoxicants. Translated from the German by David Jacobson. New York: Pantheon Books, 1992.
Autor:
Félix E. F. Larocca MD