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Chocolate: Can you Finish the Puzzle?

eshuster's picture

Chocolate is a food we are all familiar with and occasionally develop cravings for. Why we develop these cravings (intense desires to eat particular foods [6]) is an interesting area of research. Usually at emotional lows [1] or times of boredom cravings begin to arise. It was found that 40% of women and 15% of men have admitted to developing chocolate cravings [10]. The difference in gender frequency will be further explored. It is obvious, by the availability and vast consumption, that chocolate has some mysterious power; it is very palatable and can elevates one’s mood. How? It is a substance that we all love and yet it consists of over 300 known chemicals [8] and many more that have yet to be discovered.

With its growing list of chemicals, chocolate is our therapy (that need no appointment) [4] and our prescription drug. Usually if a product is attractive in both taste and emotional effect, like chocolate, it is in high demand and integrates into the fabric of daily life. [2]. Chocolate can be enjoyed anywhere, from the streets of Paris (in a Nutella filled crepe), to a local Wawa (in a bag of M&Ms) to Latin America (in a spiced chocolate drink, as was its original form of consumption). This substance elevates moods, but how?

With the new age of information available via the world wide web, the mystery of exactly how chocolate elevates moods, provides personal therapy and can self medicate us is still unclear. Many theories and studies have come up with little or no cumulative data just tiny pieces of a huge puzzle. It has been found that chocolate has an impact on the brain’s neurotransmitters acting like an antidepressant. Studies in the US have focused on learning how each chemical contributes to the overall effect but the interactions between these elements has been ignored.

The combinations and interactions are crucial for chocolate’s ability to enhance one’s mood. This paper uses tryptophan, as the main example, of how an element, individually, aids in mood elevation, in this case, by increasing serotonin levels. This paper also proposes the effect of chocolate, in terms of all its chemical consumption, as a form of therapy and self-medication to the individual consuming it.

Although studies have researched the effects of some chemicals, individually, with the repetitive conclusion that chemical levels in chocolate are too low to illicit any effect. It is this paper that will take into consideration the ability of these chemicals to interact with one another to enhance and amplify their biological effects on the body at low dosages. It would be pointless to study the make up of a cake by researching its individual ingredients separately because it is the interactions among the ingredients that differentiate that cake from a cookie.

Obviously, chocolate makes us just a little happier than before the first bite. It increases feelings, elevates our mood and reduces inner tension [6]. It is a versatile ingredient that can be utilized in both savory and sweet dishes. With the knowledge that we will elevate our mood after the chocolate is consumed, our brain/mind begins to feel cravings which can be explained by thinking about self medication, addiction, psychoactive substances and emotional eating theories [4]. Why is chocolate so addictive? It is because feeling happier and being in a better mood that is addictive [6].

A mood elevation is one that all people desire, especially women prior to menstruating, explaining why women crave chocolate every month. One of its chemicals, magnesium, is a common mineral that relaxs muscle contraction. In menstruating women, ovarian hormones and mineral deficiencies are common [7]. A deficiency in magnesium can aid in developing painful abdominal cramps that are experienced monthly. With the consumption of chocolate, magnesium is acquired (even at low levels) and neurotransmitters that act as antidepressants. With reduced cramping and a source of antidepressants, what woman wouldn’t crave chocolate monthly? This explains the gender discrepancy among men and women.

A group who self-medicates with chocolate, like menstruating women, are likely to have personality traits associated with hysteroid dysphoria (examples: Seasonal Affective Disorder (depression in the winter) and PMS [3]), episodes of depression. [1, 3]. Cravings are one of two factors that affect one’s attitude towards chocolate. [1]. These factors fall into two subcategories that explain the emotional connection one has with chocolate.

The two subcategories include the following: -1- a mentality of addiction/obsession, a mood booster or distraction and -2- associating chocolate with negative experiences like unattractiveness, depression, guilt, weight gain and sickness [1]. These two very different attitudes of chocolate are necessary to explore cravings and the ability to self medicate oneself with substances normally available through prescription only. If you are in subcategory 2 then you would be in the 60% of women or 85% of men who do not crave chocolate or refuse to act on the craving.

Once attitudes were established, researchers found subjects to participate in a study that attempted to determine what elements in chocolate elevate one’s mood. Is it the taste? Pure Psychology? Or physcial impression? Groups were exposed to both happy and sad music where they were given chocolate or carob (chocolate substitute as a placebo) to test taste, psychology and physical effect. It was concluded that taste attracts cravings in chocolate lovers elevate moods by the concluding observation that during sad music more chocolate was consumed than during happy music and overall more chocolate than carob was eaten. [1].

The study’s conclusion was confirmed by data of another experiment consisting of brown chocolate, white chocolate and cocoa powder. Results demonstrated that although cocoa powder has the same substances as does chocolate it does not satisfy one’s craving, as in comparison with white chocolate that contains the least amount of chemicals because it lacks cocoa. [1]

These studies found links to both mood elevation and the necessity for taste but do not further explore what chemicals contribute this feeling. What function might they serve and how? Not only does chocolate contain minerals, as previously discussed, but it also contains neurotransmitters, opioids, flavenoids, stimulants, and amino acids [8]. Each chemical has its own function in the body. Tryptophan, an essential amino acid, is a precursor for the monoamine neurotransmitter serotonin, synthesized in neurons in the central nervous system (CNS). [10]. Serotonin influences and/or regulates sleep, anger, aggression, vomiting, appetite, impulse control, and mood elevation. [4]. If the concentration of serotonin is enhanced by chocolate then the discovery establishes a link between serotonin, mood and craving (as they are all associated with chocolate). But, how?

Approximately 90% of tryptophan is synthesized in the gastrointestinal tract. It circulates through the blood, at low levels and stored in platelets. In order to synthesize serotonin, tryptophan must be transported across the blood brain barrier (BBB) where it will be converted into serotonin by a short metabolic pathway to two enzymes- tryptophan hydroxylase (TH) and amino acid decarboxylse (AAD) for conversion to serotonin. [7]. 5-HT (5-Hyroxytrptamine) receptors located on the membrane of nerve cells, mediate serotonin. [7].

Although overly simplified, tryptophan creates serotonin which elevates mood; the increase in serotonin levels by tryptophan is much more complicated. Tryptophan and neutral amino acids compete for the same transporting element from the body to the brain. The ration of tryptophan to neutral amino acids determines whether tryptophan can be delivered across the BBB. [1].

Research was performed and found that individuals who suffer from hysteroid dysphoria crave carbohydrates. When suffering from the disorder, as stated above, individuals experience repeated periods of depression (probably caused by low serotonin levels). In the body, the increase of carbohydrates activates insulin to facilitate the uptake of most amino acids into the cell, excluding tryptophan. If effect, the ratio of tryptophan to neutral amino acids increase so that tryptophan can be transported through the BBB to the brain where TH will convert tryptophan to thereby increase its serotonin synthesis and concentration. [1].

Opposite results were found in the same study with protein. When these individuals consumed protein they experienced a greater degree of depression, aggressiveness and mood sensitivity. This occurs as a result of the tryptophan to neutral amino acid ratio because the intake of proteins means the intake of more neutral amino acids without any insulin activation. [1]. The fallacy here is that eating more carbohydrates will increase one’s mood. Unfortunately, more factors must be taken into consideration. Only meals that comprise about 2% of proteins or less will experience the increased tryptophan transport. When the percentage is raised to as little as 5% of protein, this effect is no longer observed. Chocolate is a high carbohydrate containing food, however, it consists of approximate 13% protein. [1]. Do you see the problem?

Serotonin has an inhibitory effect on norepinephrine; when depleting, serotonin removes the inhibitory influence and control of behavior including learning and memory. [5]. Antidepressants, like MAOI, will prevent neurotransmitters, like serotonin, from degradation by monoamine oxidase to increase their concentrations in the brain (synthesis continues but degradation is halted, producing the build up of serotonin). [7].

Through detailed studies scientists explored how tryptophan affects serotonin levels which then affect mood. Unfortunately, studies found that levels of tryptophan in chocolate are too small to affect serotonin levels. This may be the case when viewed through a narrow mind but try to consider the other 299 chemicals (more than 299 because some are unknown) present in chocolate that may interact with tryptophan to enhance and amplify its effect. Many other chemicals exist in chocolate including the following: Threobromine, caffeine, N-oleoylethanolamine, N-linoleoylethanolamine, anandamine, norepinephrine, flavenoids, histamine, salsolinol, methyltetrahydroisoquinoline, telemethylhistamine, spermidine, p-tyramine, 3-methyloxytyramine, tryptoamine, spermine, phenylethylamine, magnesium, opioid chemicals and obviously tryptophan. [1-10].

In chocolate, the culmination of the variety of chemicals greatly affects their individual functions in the body. It is interesting to look at how much research has been performed with individual chemicals and not the possible interactions between these chemicals. Let’s look at the roles of some of the chemicals to see if there are similarities in function or a potential for interaction. Anandamides is a neurotransmitter that can increase memory and occupies the same site, in the brain, as cannabis. Phenylethylamine, like amphetamine, can also be treated with MAIO (if deficient) and improves focus. Caffeine, an alkaloid compound, acts as a stimulant to restore alertness and increase the capacity for mental and/or physical labor. Finally magnesium is necessary to relax muscle contraction. [1]

With the variety of functions, these chemicals can interact among themselves and they do. Without any study, the functions of the chemicals like increased memory, improved focus, restoration of alertness and, with serotonin, increase mood can easily interact with one another to inevitably become a college student’s best friend. Unfortunately, levels of chemicals found in one bar of chocolate were several orders of magnitude less than those needed to produce pharmacological action. [1]. The question still remains, how can chocolate improve mood?

Additional studies found that chocolate contains two chemicals, N-oleoylethanolamine and N-linoleoylethanolamine, that inhibit natural breakdown of anandamide (the brain has natural receptors for breakdown) while also providing an additional supply of anandamide. In effect, chocolate (with very low concentrations of each chemical) has the capacity to provide the inhibition of breakdown (builds up naturally produced anandamides) of anandamides and add more anandamide to the body. Too much anandamide can create a feeling of euphoria (being high). [9]. This example is just one of many interactions of chocolate’s chemicals with each other that can enhance their individual effect without increasing the consumption of chocolate.

Another example of an increase effect of chocolate on the body with low amounts of chemicals occurs with threobromine and caffeine. Although threobromine is a weak stimulant, with caffeine these two chemicals can enhance mood. With the interactions of threobromine, caffeine and phenylethylamine the body also experiences an increase in alertness.

It is a shame that research is focused on individual chemicals rather than a possible cumulative effect. There is so much research being done on chocolate as a medicine, a mood adjustor, and a form of therapy, however, the understanding of interaction in chocolate are very slim. In order to complete a complicated puzzle, it takes more time to figure out how the pieces fit together than established that all the pieces are present. Even if some pieces are missing, in the puzzle, the brain can develop its own illusion and outcome by looking at the puzzle with the empty spaces focused at the eye’s blind spot.

Through this long analysis it is clear that analyzing tryptophan and its effects on serotonin cannot be fully understood without looking at the big picture. We explored cravings, mood changes, tryptophan activity and function, and chemicals present in chocolate to conclude that this self medication because a medicine is a (are) chemical(s) that illicit a chemical reaction in the body. It cannot be fully understood without looking at other participants in the picture. Anandamine would not affect the brain if not for the two breakdown inhibitors. A futile study, would observe Anandamine’s individually and how it directly impacts the brain. The study would then conclude that Anandamine levels in chocolate are too low to affect brain activity which ignores the presence and effect of N-oleoylethanolamine and N-linoleoylethanolamine.

Although chocolate is a phenomenon that enhances mood through self medication. It acts as ones own therapy to life. It is better to phase your own problems when you’re happier than when depressed. It is also important for researchers to discover what links these chemicals together to create an unforgettable sensation in one’s mouth.


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  3. Moller, S. Serotonin, carbohydrates and atypical depression. Pharmacol Toxicol. 71(suppl 1):61-71. (1992).
  4. Parker G, Parker I and H. Brotchie. Mood state effects of chocolate. Journal of Affective Disorders. 92(2-3): 149-159. (2006).
  5. Riedel W, Klaassen T. and J. Schmitt. Tryptophan, mood, and cognitive function. Brain, Behavior and Immunity. 16:581-589. (2002).
  6. Rogers P. and H. Smit. Food Craving and Food “Addiction”: A Critical Review of the Evidence from Biopsychosocial Perspective. Pharmacology Biochemistry and Behavior. 66(1): 2-14. (2000).
  7. “Serotonin.” Wikipedia. 5/2/2007

8. Wan Y, Vinson J, Etherton T, Proch J, Lazarus S and P Kris-Etherton. Effects of cocoa powder and dark chocolate on LDL oxidative susceptibility and prostaglandin concentrations in humans. American Journal of Clinical Nutrition. 74(5): 596-602. (2001).

  1. Willet, E. Why we Crave Chocolate. Science Columns. (2001).

10. Yanovski, S. Sugar and Fat: Cravings and Aversions. Journal of Nutrition. 133(3): 835S-837S. (2003).




Christopher Hagedorn's picture

Good article

Thanks for the interesting read! I believe this article provides some much needed insight into the pharmacology of chocolate. I would love to see an updated version that takes into account any new research published on the subject at hand. How well do the oleoylethanolamines in chocolate inhibit anandamide breakdown? Do the metabolites of theobromine such as 3-methylxanthine and 7-methylxanthine have stimulant properties as well? How much are the brain's levels of phenethylamine raised following chocolate consumption, and how quickly is it metabolized?
I hope you can help me find the answers to some of these questions. I am a physics student at the University of Aarhus, Denmark with a great interest in molecular biology and pharmacology of naturally occurring substances.

Christopher Hagedorn