1997 2ND PLACE

The real reasons for loving chocolate

By Mark Howarth

Europe first encountered chocolate when Christopher Columbus brought back a few cocoa beans to a distinctly unimpressed King of Spain. It became popular in Europe after the return of Cortes from the Aztecs, a civilisation that used cocoa as currency and considered it the food of the gods. Here began the world's love-affair with chocolate. The immense popularity today is illustrated by a study suggesting that about 40% of women and 15% of men in North America experience a craving for chocolate. Significantly other sweets are not an effective substitute, so it is not simply the sugar that causes the craving.

Studies like this make one suspect that there is more to the charm of chocolate than simply the pleasant experience of eating it - the aroma, the texture, the sweetness, the countless calories! Are there some ingredients which directly have an effect on one's mood, which subtly influence the chemistry of the brain?

The answer is yes: a range of studies have opened the door on the pharmacological fire-power that may be at the heart of chocolate's extraordinary popularity. The most familiar is caffeine which produces the feeling of increased well-being and alertness familiar to (caffeinated-) coffee drinkers.

Theobromine, almost identical to caffeine, is also found in chocolate but has more modest effects. A bar of chocolate is thought to contain a sufficient dose of caffeine and theobromine to have an impact on a person's mood. But chocolate's chemical secrets by no means end here. The pleasure produced from chocolate may be down to traces of phenylethylamine. This has a structure a whisker away from amphetamine, also known as "speed", which mimics many of the effects of adrenaline in the body.

Phenlyethylamine is a stimulant even more powerful than amphetamine; in higher doses it produces euphoria, leaving one buzzing with energy and confidence.

Dr. Daniele Piomelli and his team at the Neurosciences Institute in San Diego have taken the story a major step further: they have succeeded in isolating cannabinoids from chocolate. Cannabinoids are responsible for the "high" and enhanced sensitivity to sight and sound experienced after smoking cannabis/marijuana.

As with caffeine and phenylethyIamine, they have most of their effects by triggering speciflc receptors in the brain. What's more, the active ingredient of marijuana is a pale imitation of the brain's own trigger for the cannabinoid receptor; one of the cannabinoids in chocolate, as a certain brand of cola might say, is the real thing.

The cannabinoid receptor is actually designed to bind the neurotransmitter anandamide. Anandamide, which not inappropriately gets its name from the Sanskrit word for bliss is found in chocolate! In addition, chocolate contains two anandamide mimics. These can't bind to the cannabinoid receptor themselves, but instead keep occupied the enzyme responsible for degrading anandamide. Thus these two mimics use an indirect route to achieve the same end: increasing the anandamide levels in the brain.

While the presence of these powerful compounds is of interest in itself, nobody would claim that they get a 'high' from eating chocolate; contentment is about as far as it goes. What the cannabinoids may do is to magnify the sensory pleasures, intensifying appreciation of the taste and aroma.

The trace of cannabinoids in chocolate could also conceivably produce faint therapeutic benefit. A lot of effort has gone into developing cannabinoids for medical use. They have proven abilities in pain-killing, relieving nausea and reducing the high pressure in the eye that causes glaucoma.

Also some cells in the immune-system have cannabinoid receptors on their surface, so that anandamide and its mimics are able to combat inflammation. The challenge for the drug-designers is to find compounds with the medicinal properties but without the 'high' that accompanies even quite low doses.

Some might say that blissful relaxation isn't the worst side-effect in the world. However, if you are using these cannabinoid drugs every day, other side-effects such as dizziness and mild hallucinations would rather interfere with the rest of your life. Certainty, if someone tells you the chocolate bar they are wolfing down is "purely for medicinal purposes", don't be fooled.

The San Diego team's discovery could also provide a solution to one of the nagging problems of modern life. A commonly observed effect of smoking marijuana is an increase in appetite. This is probably through the influence of cannabinoids in the hypothalmus, a part of the brain controlling hunger. Could the cannibinoids in chocolate have a similar effect on appetite, leading to the involuntary sensation that one bite is never enough?