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…
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Autor:
Félix E. F. Larocca
MD