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By Charlea T. Massion, MD
Chocolate is great
Chocolate is grand
Melts in your mouth
Melts in your hand1
Many women have a passionate and ambivalent relationship with chocolate. Chocolate is associated with romance (a seductive gift, a lover’s apology) and solace (taking to bed with a box of tissues in one hand, a box of chocolates in the other). Many of us grew up believing chocolate consumption was associated with acne, obesity, and premenstrual binges. In recent years, chocolate has been recast as a benign, even healthful food. This article will explore some studies of chocolate and women’s health.
As a taste of chocolate’s past and future, the Swedish botanist Linnaeus titled the genus of cacao trees Theobroma, from theo for god and broma for food. Theobroma cacao has more than 20 types that are divided into three major groups: criollo (native); forastero (foreign); and a cross between the two, trinitario (sent from heaven).
Theobromas are small, rather delicate evergreens that thrive in hot, humid climates only if protected from direct sun. As a middlestory tree in Mesoamerican rain forests, wild cacao often grows under Madre de cacao (Gliricidia sepium), a larger tree that provides semi-darkness, nutrients from both leaf fall and the nitrogen-fixing bacteria in its roots, plus minute traces of coumarin that poison animals that crave cacao beans. However, the cacao depends on cacao-seeking vertebrates to reproduce, because its pods, even when fully ripe, do not drop off the tree.2 In the rain forest, cacao seeds are dispersed by bats, rats, monkeys, and squirrels that gnaw through the pods to procure the sweet, mucilaginous pulp around the bitter seeds. (No studies have been done to ascertain if female, non-human vertebrates are more intense than males in their cacao bean-seeking behavior.)
Cacao grows in a narrow band within 20 degrees of the equator, with the islands of Cuba at the northern boundary and Reunion at the southern boundary.3,4 Cacaos begin to bear football-shaped fruit that are 7-10 inches long at four years of age. Fully mature at seven years, they can live up to 100 years, producing dozens of pods annually. Ripening pods change from green to red or purplish-yellow and are hand-harvested with a special machete. Each pod contains 20-50 seeds.3
Please don’t mention the chemical connection
Chocolate makes in my head
It’s Swiss Miss I’m drinkin’
It’s Hershey bars I’m thinkin’
If I can’t be in love
I’ll have a truffle instead1
Food or drug? Chocolate is the most commonly craved food in North America; one landmark study documents that chocolate accounts for almost half of all food cravings.4 Is chocolate craving an indication of hypomagnesemia? If so, why don’t millions of humans crave nuts and whole-grains instead? Is chocolate appealing simply because it is high in fat and sugar, or does it have drug-like effects? Chocolate does contain biologically active constituents; however, other pharmacologically related foods go unmentioned in art and science. Are chocolate cravings physiologically or psychologically based?
Chocolate’s pharmacological components include biogenic amines, methylxanthines, and cannabinoid-like fatty acids. (Consider eating a piece of chocolate as you review these.)
Several biogenic amines, notably tyramine and phenylethylamine (PEA), are present in chocolate. These amines have sympathomimetic effects, and, like nicotine, stimulate dopamine release in the brain. PEA, also known as the "love drug," is associated with various euphoric states, including the ecstasy experienced with cocaine, amphetamines, and occasionally, long-distance running.5 PEA is distributed throughout the brain and is quickly metabolized by monoamine oxidase-b and aldehyde dehydrogenase to phenylacetic acid. PEA is a neuromodulator of mood, and depression is associated with reduced levels of PEA.4
Chocolate contains sufficient PEA (0.4-6.6 mcg/g) to convince some researchers that chocolate craving may be an attempt to increase the brain’s PEA level and improve mood. However, certain cheeses and sausages contain much more PEA and tyramine, yet hardly have the following of chocolate. Also, since the half-life of PEA in serum is only 5-10 minutes, PEA ingestion may not raise systemic concentrations enough to influence the central nervous system level.4
MDMA (3,4 methylenedioxymethamphetamine, or Ecstasy) and PEA are structurally similar, and both are amphetamine analogs. One study of seven MDMA addicts noted that all had intense chocolate cravings and frequent chocolate binges. This study has led some experts to state, "This association of chocolate cravings with certain drug-induced psychoses suggests that the psychopharmacologic effects of chocolate deserve further attention."4 However, as any intern who has been in emergency rooms between midnight and 5 am (possibly consuming machine-dispensed chocolate in large quantities themselves) knows, there are no chocolate overdose victims hooked up to respirators and no chocolate addicts in acute withdrawal screaming, cursing, and/or seizing as various intravenous drips modulate their central nervous system functions.
Chocolate also contains alkaloid methylxanthines, primarily theobromine (3,7 dimethylxanthine) and caffeine (1,3,7-trimethylxanthine). Both compounds are highly lipid-soluble and easily cross the blood-brain barrier. In the brain, methylxanthines are competitive in-hibitors of adenosine. Caffeine also facilitates the re-lease of epinephrine, amplifying its stimulatory effects.
Less research has been done on theobromine, which seems less stimulating and takes longer to reach peak pharmacologic effects than caffeine does. Administration of theobromine in capsules does not reduce chocolate craving symptoms, so it may have insignificant physiological and psychological effects. The presence of caffeine is unlikely to explain "chocolate addiction," since chocolate contributes little to most people’s daily caffeine intake.6 However, some speculate that caffeine and theobromine act synergistically, producing a greater effect than either alone.
Chocolate contains biologically active compounds that target endogenous cannabinoid receptors in the human brain, causing effects similar to those of cannabinoid drugs (e.g., euphoria and heightened sensitivity). Anandamide, which means "internal bliss," is an endo-genous brain lipoprotein that functions as an internal cannabinoid neuromodulator. Acting in the nucleus accumbens septi, cannabinoids increase activity of the mesolimbic dopamine reward system by potentiating endogenous opioid receptors, and possibly by altering the action of other neurotransmitters (e.g., dopamine, histamine, serotonin, acetylcholine, norepinephrine, and prostaglandins).4
Chocolate contains N-acylethanolamines, which may mimic or potentiate anandamide’s activity, producing a sense of well-being.7 Another group, however, disputed this theory,8 which remains controversial (see Alternative Therapies in Women’s Health, March 1999).
|Mineral content for cocoa powder and chocolate liquor per 100 g|
|Nutrient||Cocoa Powdera||Chocolate Liquorb|
|1495.50 mg||1023.80 mg|
|13.86c mg||13.52 mg|
|593.64 mg||314.17 mg|
|7.93 mg||4.29 mg|
|4.61 mg||2.36 mg|
a Cocoa powder, 10% fat.
b Chocolate liquor (unsweetened, bakers chocolate), 50% fat.
c USDA Agriculture Handbook No. 8-19: cocoa powder, unsweetened.
Source: Knight I, ed. Chocolate and Cocoa: Health and Nutrtion. Oxford: Blackwell Sciences, Ltd.; 1999.
With all that in mind, which component of chocolate causes cravings, "chocolate addiction," and chocolate-induced behaviors? One study that attempted to separate chocolate’s pharmacological activity from its sensory factors found no physiological basis for chocolate craving. This crossover study compared chocolate bars, cocoa in capsules, white chocolate (cocoa butter without chocolate’s other components), white chocolate plus cocoa capsules, no chocolate, and placebo on the satiation of chocolate craving in 72 students.9 Only 34 students completed at least one observation for each "treatment." (Apparently the appetite of this population for participation in scientific studies was very easily satisfied.) Milk chocolate, for better or worse, served as the standard for craving relief. Results: White chocolate received intermediate scores, and cocoa capsules brought no greater craving relief than placebo.
Anecdotally, many women report that their choco-late craving increases premenstrually. One placebo- controlled, double-blind, crossover study tested the effects of progesterone and alprazolam on premenstrual craving for chocolate or sweets.10 Subjects in this study were in the Premenstrual Syndrome (PMS) Program at the University of Pennsylvania, were between the ages of 18 and 45, and had regular menses and no current major psychiatric diagnoses. Forty-four women met the criteria for cyclic chocolate craving and 44 met the criteria for cyclic sweet craving; 34 women satisfied criteria for both. Records were kept for two baseline cycles. During the third cycle, subjects were treated with placebo, alprazolam, or oral micronized progesterone. Treatments were administered from day 21 until the second day of menses. Results: Neither progesterone nor alprazolam decreased either chocolate or sweet craving. (Although progesterone has been used for many years to treat PMS, progesterone actually may cause or amplify premenstrual anxiety and depression, so the results of the progesterone arm of this study are hardly surprising.)
How about modulation of affect and craving in "chocolate addicts"? One study of 40 women explored the interaction of mood and chocolate intake.11 Twenty self-identified "chocolate addicts" and 20 controls kept seven-day diaries of hunger, mood, craving intensity, and amount of chocolate consumed. The chocolate addicts ate significantly more chocolate more often than controls did. They also had higher guilt, depression, and craving scores; lower relaxation and contentment scores before eating chocolate; and more guilt without relief of depressive feelings after eating chocolate. Chocolate addicts scored higher than controls on indices of depression and disordered eating. Consuming chocolate, unfortunately, did not improve their indices. All around, "chocolate addicts" were unable to enjoy eating chocolate, and their moods remained anxious and/or depressed, even with high chocolate intake.
Cocoa is warm
Whatever the form
It’s always a thrill
Chocolate is love1
Chocolate may be good for the heart both figuratively and literally. Do you know that if you found chocolate purchased by your mother during her childhood, you could use it to bake a cake today? And that bar of melted chocolate you found at the bottom of a backpack last used 10 years ago is still OK to eat? Chocolate doesn’t spoil because it has very high concentrations of antioxidants, and it is possible that these antioxidants have beneficial cardiovascular effects.
Chocolate contains more catechins (polyphenolic flavonoids) than tea; dark chocolate contains 53.5 mg/100 g; milk chocolate contains 15.9 mg/100 g; and an infusion of black tea (1 g/100 mL water) contains 13.9 mg/100 mL. However, the catechin thought to have the most beneficial antioxidant effects, (-) epigallocatechin gallate (ECGG), occurs in tea but not chocolate.12 (See Alternative Therapies in Women’s Health, October 1999.)
For those concerned about fat intake, cocoa powder is an option, containing almost no fat but retaining antioxidant effects. Cocoa is a good option because it has more phenols by weight than bakers (unsweetened) chocolate, which in turn has more phenols than milk chocolate. A 41 g (1.5 oz) piece of milk chocolate contains 205 mg phenol, equivalent to the 210 mg phenol found in a 140 mL (5 oz) serving of red wine. An in vitro experiment found that cocoa phenols inhibited human low-density lipoprotein (LDL) oxidation by 75%,13 and a clinical study found that LDL oxidation lag-time increased in the blood of 12 male volunteers after ingesting 35 g of cocoa.14 Cocoa also has been shown to inhibit platelet aggregation.15
Chocolate also contains significant amounts of potassium, iron, magnesium, zinc, and copper (see Table); a study using three-day dietary records found that chocolate is the largest source of mean daily copper intake.16 So if you are a chocolate lover, you can feel fine about keeping chocolate in your diet!
(Thanks to Gary Ladd and Robert Steinberg, MD, for review of the manuscript.)
1. "Chocolate is Love," a song by the Chenille Sisters.
2. Young AM. The Chocolate Tree: A Natural History of Cacao. Washington, DC and London: Smithsonian Institution Press; 1994.
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8. Di Marzo V, et al. Trick or treat from food endocannabinoids. Nature 1998;396:636.
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13. Waterhouse AL, et al. Antioxidants in chocolate. Lancet 1996;348:834.
14. Kondo K, et al. Inhibition of LDL oxidation by cocoa. Lancet 1996;348:1514.
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16. Joo SJ, Betts NM. Copper intakes and consumption patterns of chocolate foods as sources of copper for individuals in the 1987-88 nationwide food consumption survey. Nutr Res 1996;16:41-52.