This paper reflects the research and thoughts of a student at the time the paper was written for a course at Bryn Mawr College. Like other materials on Serendip, it is not intended to be "authoritative" but rather to help others further develop their own explorations. Web links were active as of the time the paper was posted but are not updated.
2004 First Web Paper
While thinking of things to put in a gift basket for a friend who was in the hospital, my roommate turned to me with some of her German chocolates and inquired if indeed it was true that chocolate makes a person happy. "It has something to do with endorphins in the brain, right?" she asked me. I decided to do some research. Does chocolate make you happy by effecting the brain? Intrigued, I turned to the Internet and searched for "chocolate on the brain." Lo and behold, I discovered that the over 300 chemicals that compose chocolate have numerous and varied effects on our bodies through the nervous system (1).
Chocolate can affect the brain by causing the release of certain neurotransmitters. Neurotransmitters are the molecules that transmit signals between neurons. The amounts of particular neurotransmitters we have at any given time can have a great impact on our mood. Happy neurotransmitters such as endorphins and other opiates can help to reduce stress and lead to feelings of euphoria. As connections between neurons, they are released from the pre-synaptic membrane and travel across the synaptic clef to react with receptors in the post-synaptic membrane. Receptors are specified to react with particular molecules which can trigger different responses in the connected neurons. The proper neurotransmitter can trigger certain emotions.
It turns out that my roommate was correct in her assertion that chocolate affects the levels of endorphins in the brain. Eating chocolate increases the levels of endorphins released into the brain, giving credence to the claim that chocolate is a comfort food. The endorphins work to lessen pain and decrease stress (2). Another common neurotransmitter affected by chocolate is serotonin. Serotonin is known as an anti-depressant. One of the chemicals which causes the release of serotonin is tryptophan found in, among other things, chocolate (1).
One of the more unique neurotransmitters released by chocolate is phenylethylamine. This so called "chocolate amphetamine" causes changes in blood pressure and blood-sugar levels leading to feelings of excitement and alertness (1). It works like amphetamines to increase mood and decrease depression, but it does not result in the same tolerance or addiction (3). Phenylethylamine is also called the "love drug" because it causes your pulse rate to quicken, resulting in a similar feeling to when someone is in love (4).
Another interesting compound found in chocolate is the lipid anandamide. Anandamide is unique due to its resemblance to THC (tetrahydrocannabinol), a chemical found in marijuana. Both activate the same receptor which causes the production of dopamine, a neurotransmitter which leads to feelings of well being that people associate with a high. Anandamide, found naturally in the brain, breaks down very rapidly. Besides adding to the levels of anandamide, chocolate also contains two other chemicals which work to slow the breakdown of the anandamide, thus extending the feelings of well-being (4). Even though the anandamide in chocolate helps to create feelings of elation, the effect is not the same as the THC in marijuana. THC reacts with receptors more widely dispersed in the brain and is present in much larger amounts. It would take twenty-five pounds of chocolate to achieve a similar high to that of marijuana (1).
Theobromine is another chemical found in chocolate that can affect the nervous system. Besides having properties that can lead to mental and physical relaxation, it also acts as a stimulant similar to caffeine. It can increase alertness as well as cause headaches. There is much debate as to whether or not caffeine even exists in chocolate. Some scientists believe that it is the less potent theobromine which is solely responsible for the caffeine-like effects (5).
When examining the effects of chocolate on the nervous system, it is also important to point out that chocolate does not treat all nervous systems the same. Many animals, for example, can be killed by the chemicals in chocolate. Theobromine in particular does not metabolize as quickly in other animals such as dogs and horses (1).
Chocolate has a long history associated with feelings of well being. It has been favored by people ranging from the ancient Aztecs to high society Victorians to Popes. Chocolate also has a history of being a known aphrodisiac (6). This makes sense when you combine phenylethylamine's ability to quicken the heart, the feelings of euphoria from anandamide, theobromine's power to cause relaxation, and the other neurotransmitters sending pleasurable feelings throughout the brain. Even the names associated with chocolate imply its power. Anandamide is derived form the word ananda which is Sanskrit for bliss and theobromine can be traced back to the Greek word theobroma meaning "food of the gods" (6).
It seems to be true that eating chocolate can increase feelings of euphoria as well as decrease stress and pain, but is it possible that chocolate can be addictive? There are many people out there who consider themselves to be addicted to chocolate, partly because of its mood-enhancing qualities. Many questions, however, still remain regarding if chocolate can, like the drugs with similar chemicals and effects, be an addictive substance. The majority of scientists seem to agree that chocolate is not addictive. Some go as far to say that chocolate is merely a kind of placebo that only causes these effects because people believe that it will. Chemicals such as phenylethylamine and anandamide can be found in other edibles in much greater amounts but they don't seem to have the same effect (1). There are plenty of self professed chocoholics out there who would, however, refute this claim and who continue to proclaim the wonders of chocolate.
It is also important to remember that not all chocolate is created equal. The strength of chocolate depends greatly on how it is manufactured. The cacao bean, from which chocolate is derived, has a naturally bitter taste and is greatly diluted by sugars and other ingredients. In the United States, something needs only to have 10% cacao in it to be considered chocolate (5). When examining my roommate's collection, most of which is from Germany, I found that cacao levels were around 30%, the dark chocolate being slightly higher. It seems that in diluted chocolate, the effects would be minimal.
I think it is quite fascinating that a food such as chocolate can have such an effect on the operations of our brain and thus our perceptions of the world. Since I met my roommate over a year ago, I have significantly increased my chocolate intake. I also think I'm a happier person than I was before we met. Could it be that the chocolate I consume now almost on a daily basis has something to do with my subtle transformation in mood? I would like to think not, but it is an interesting thought. I do, however, instinctively find myself reaching over to the chocolate stash whenever I start feeling a little depressed or overwhelmed and it always seems to make me feel better.
1)BBC News ,
2)"Endorphins: The Body's Stress Fighters" ,
4)"All About Chocolate: Chocolate and your Health" ,
6) "Chocolate: Melting the Myths" ,
7) Neuroscience for Kids-Chocolate and the Nervous System ,
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