Your Brain on Food

How chemicals control your thoughts and feelings.

Chocolate: The Good, the Bad and the Angry

Eating chocolate can produce rage, paranoia and anger.

In 1648, according to the diary of English Jesuit Thomas Gage, the women of Chiapas Real arranged for the murder of a certain bishop who forbade them to drink chocolate during mass. In an ironic twist, the pontiff was ultimately found murdered after someone had added poison to his daily cup of chocolate.

Was this an act of blind rage by the women of Chiapas Real or justifiable homicide? For a small percentage of the population, eating chocolate can produce rage, paranoia and anger that occur without warning. Fortunately, for most of us, this is not the typical reaction to eating chocolate.

In order to understand why chocolate is so enjoyable for some while it induces uncontrollable rage in others we need to consider the contents of most dark chocolates. Chocolate contains an array of compounds that contribute to the pleasurable sensation of eating it. Many of these compounds are quite psychoactive if they are able to get into our brains. Are they the reason that we love chocolate so much? Are they the reason that some people fly into fits of anger? The answer to both questions is, of course, yes. However, as is true for so many of the things we eat that affect our brain, it's not all that simple.

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Chocolate usually contains fats that may induce the release of endogenous molecules that act similar to heroin and produce a feeling of euphoria. German researchers reported that drugs that are able to block the actions of this opiate-like chemical produced by eating chocolate prevented the pleasure associated with eating chocolate. Chocolate also contains a small amount of the marijuana-like neurotransmitter called anandamide. Although this molecule can easily cross the blood-brain barrier, the levels in chocolate are probably too low to produce an effect on our mood by itself.

Chocolate contains some estrogen-like compounds, a fact that may explain a recent series of reports showing that men who eat chocolate live longer than men who do not eat chocolate (the effect was not seen for women who have an ample supply of their own estrogen until menopause). However, estrogen is not likely to cause rage, only the urge to shop.

Let's focus upon those women of Chiapas Real again. In contrast to its effects on men, women more often claim that chocolate can lift their spirits. In a study of college students and their parents, 14% of sons and fathers, 33% of daughters and mothers met the standard of being substantially addicted to chocolate. Women seem to have very strong cravings for chocolate just prior to and during their menstrual cycle.

Women eat more and crave more foods in the days before the start of their period when progesterone levels are low. This is when premenstrual symptoms tend to appear as well. Chocolate may provide an antidepressant effect during this period. In one study researchers found that women in their fifties often develop a sudden strong craving for chocolate. It turns out that most of the women had just entered menopause and were on standard form of replacement regiment consisting of 20 days estrogen 10 days progesterone. The chocolate cravings developed during the days on progesterone. Why?

Chocolate contains magnesium salts, the absence of which in elderly females may be responsible for the common post-menopausal condition known as chocoholism. 100 mg of magnesium salt is sufficient to take away any trace of chocoholism in these women: but who would want to do that? And finally, a standard bar of chocolate contains as many anti-oxidants as a glass of red wine. Clearly, there are many good reasons for men and women to eat chocolate to obtain its indescribably soothing, mellow, and yet euphoric effect.

OK, what about the anger? How might that happen? Chocolate contains phenethylamine (PEA), a molecule that resembles amphetamine and some of other psychoactive stimulants. When chocolate is eaten, PEA is rapidly metabolized by the enzyme MAO. Fifty percent of the PEA you consume in a chocolate bar is metabolized within only ten minutes. Thus very little PEA usually reaches the brain, thus contributing little or no appreciable psychoactive effect without the use of a drug that can inhibit MAO. Could this happen? Possibly yes. MAO levels are at their lowest level in premenstrual women, which is the time when women most crave the soothing effects of chocolate. In addition, chocolate also contains small amounts of the amino acid tyramine.

Tyramine can powerfully induce the release of adrenaline, increase blood pressure and heart rate and produce nausea and headaches. Usually, the nasty effects of tyramine are prevented because it too is metabolized by MAO. You can see the problem: the tyramine and PEA in chocolate may slow each other's metabolism. The consequence is having both of these chemicals hang around too long in the body would be high blood pressure, a fast beating heart, heightened arousal, racing thoughts, anger, anxiety and rage. One rather controversial study claimed that inhibitors of MAO were able to increase PEA levels in the brain by 1000-fold! That's a lot and the consequences of this actually happening could be lethal. However, the potential exists for some vulnerable people to experience significant shifts in mood after eating chocolates with high cocoa powder levels.

The main point to take away from this discussion about chocolate is that plants, such as the pods from the cocoa tree, contain a complex variety of chemicals that, when considered individually, are not likely to impact our brain function. However, when considered in aggregate they may exert compound effects throughout the body; some of those effects may be desirable while others may not. Chocolate is an excellent example of how difficult it is to differentiate food from drug.

© Gary L.Wenk, Ph.D., author of Your Brain on Food (Oxford, 2010); http://faculty.psy.ohio-state.edu/wenk/

See also: Marijuana and Coffee are good for the brain. http://www.youtube.com/watch?v=2uVXs6CY2ps

Gary L. Wenk, Ph.D., is a Professor of Psychology & Neuroscience & Molecular Virology, Immunology and Medical Genetics at the Ohio State University.

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