CHOCOLATE : the Psychoactive Cocktail

More than 300 different constituent compounds in chocolate have been identified. Chocolate clearly delivers far more than a brief sugar high. Yet its cocktail of psychochemical effects in the central nervous system are poorly understood. So how does it work?

        Chocolate contains small quantities of anandamide, an endogenous cannabinoid found in the brain. Skeptics claim one would need to consume several pounds of chocolate to gain any very noticeable psychoactive effects; and eat a lot more to get fully stoned. Yet it's worth noting that N-oleolethanolamine and N-linoleoylethanolamine, two structural cousins of anandamide present in chocolate, both inhibit the metabolism of anandamide. It has been speculated that they promote and prolong the feeling of well-being induced by anandamide.

        Chocolate contains caffeine. But the caffeine is present only in modest quantities. It is easily obtained from other sources. Indeed a whole ounce of milk chocolate contains no more caffeine than a typical cup of "decaffeinated" coffee.

        Chocolate's theobromine content may contribute to - but seems unlikely to determine - its subtle but distinctive psychoactive profile. Surprisingly, perhaps, recent research suggests that pure theobromine may be superior to opiates as a cough medicine due to its action on the vagus nerve.

        Chocolate also contains tryptophan. Tryptophan is an essential amino acid. It is the rate-limiting step in the production of the mood-modulating neurotransmitter serotonin. Enhanced serotonin function typically diminishes anxiety. Yet tryptophan can normally be obtained from other sources as well; and only an unusually low-protein, high-carbohydrate meal will significantly increase its rate of intake into the brain.

        Like other palatable sweet foods, consumption of chocolate triggers the release of endorphins, the body's endogenous opiates. Enhanced endorphin-release reduces the chocolate-eater's sensitivity to pain. Endorphins probably contribute to the warm inner glow induced in susceptible chocoholics. This sensation explains why chocolate gifts are a great way to bring joy to a loved one.

        Acute monthly cravings for chocolate amongst pre-menstrual women may be partly explained by its rich magnesium content. Magnesium deficiency exacerbates PMT. Before menstruation, too, levels of the hormone progesterone are high. Progesterone promotes fat storage, preventing its use as fuel; elevated pre-menstrual levels of progesterone may cause a periodic craving for fatty foods. One study reported that 91% of chocolate-cravings associated with the menstrual cycle occurred between ovulation and the start of menstruation. Chocolate cravings are admitted by 15% of men and around 40% of women. Cravings are usually most intense in the late afternoon and early evening.

        Cacao and chocolate bars contain a group of neuroactive alkaloids known as tetrahydro-beta-carbolines. Tetrahydro-beta-carbolines are also found in beer, wine and liquor; they have been linked to alcoholism. But the possible role of these chemicals in chocolate addiction remains unclear.

        One UK study of the human electroencephalographic (EEG) response to chocolate suggests that the odour of chocolate significantly reduces theta activity in the brain. Reduced theta activity is associated with enhanced relaxation. This study needs replication.

        Perhaps chocolate's key ingredient is its phenylethylamine (PEA) "love-chemical". Yet the role of the "chocolate amphetamine" is disputed. Most if not all chocolate-derived phenylethylamine is metabolised before it reaches the CNS. Some people may be sensitive to its effects in very small quantities.

        Phenylethylamine is itself a naturally occurring trace amine in the brain. Phenylethylamine releases dopamine in the mesolimbic pleasure-centres; it peaks during orgasm. Taken in unnaturally high doses, phenylethylamine can produce stereotyped behaviour more prominently even than amphetamine. Phenylethylamine has distinct binding sites but no specific neurons. It helps mediate feelings of attraction, excitement, giddiness, apprehension and euphoria; but confusingly, phenylethylamine has also been described as an endogenous anxiogen. One of its metabolites is unusually high in subjects with paranoid schizophrenia.

        There is even a phenylethylamine theory of depression. Monoamine oxidase type-b has been described as phenylethylaminase; and taking a selective MAO-b inhibitor, such as selegiline (l-deprenyl, Eldepryl) or rasagiline (Azilect) can accentuate chocolate's effects. Some subjects report that bupropion (Wellbutrin, Zyban) reduces their chocolate-cravings; but other chocoholics dispute this.