We love chocolate. A US survey showed that people ranked it as their favourite flavour of dessert by a margin of three to one. Most people also feel somewhat guilty about eating chocolate, thinking it an unhealthy food. On the contrary, there is much evidence that, consumed in moderation, chocolate is good both for the mind and for the body.
Chocolate is derived from the beans of the cacao tree, whose Latin name is Theobroma cacao, or "food of the gods". The tree generally grows up to 12 metres tall and produces about five kilograms of cacao beans per year. Cacao is the world's third-largest agricultural export crop, and large plantations of it are found in Brazil, Bolivia, Peru, Fiji, Cuba, Zaire, Sri Lanka, Togo, New Guinea and Venezuela.
The fruit of the cacao tree has been appreciated for a long time. The Mayan Indians began to cultivate and trade cacao beans in the seventh century. The Spanish explorer Hernando CortΘs visited the court of the Aztec emperor Montezuma in the 16th century and encountered chocolate for the first time as a drink called xocoatl.
The Aztecs treated cacao beans as a great treasure and drank large bowls of frothy unsweetened chocolate. They believed the gods gave chocolate to humanity as a divine beverage, and that the drink conferred strength, vigour and an impetus to sexual prowess on those who consumed it - Montezuma reportedly drank 50 cups a day.
Cacao beans were subsequently brought back to Spain, where the chocolate drink was sweetened, to improve the naturally bitter taste. For a century, chocolate remained a secret reserved for the nobility. Eventually, the secret got out, and by the mid-1600s the chocolate drink was popular across Europe. Coffee and chocolate houses were established and chocolate-drinking became a social event.
Solid chocolate bars were first produced in England in the late 1600s. Companies all over Europe began to manufacture chocolate, and machines were invented to help production. The Cadbury Chocolate Company was founded in 1822.
On their way to becoming chocolate, the cacao beans are prised from large oblong pods, fermented in vats for four days, dried in the sun and shipped in jute sacks to chocolatiers, who crush the insides of the beans into a paste that becomes the world's favourite confection.
For many years, nutritionists regarded chocolate as a health hazard, but a report in the July 2000 edition of the American Journal Of Clinical Nutrition indicates that chocolate can be good for cardiovascular health.
Chocolate is rich in a group of chemicals called polyphenols, which are also found in other plant foods, such as tea and red wine. Polyphenols are antioxidants, meaning they inhibit a type of chemical activity called oxidation.
The polyphenols in chocolate confer cardiovascular protection in two ways. They inhibit the oxidation of LDC cholesterol, which is a principal factor in the precipitation of heart attack and stroke, and reduce the risk of atherosclerosis, or hardening of the arteries, by inhibiting blood platelets, a type of cell found in blood, from aggregating.
There is also significant scientific evidence that chocolate is a mood enhancer. One of the hundreds of chemicals found in chocolate is phenylethylamine, which stimulates the nervous system and triggers the release of endorphins, natural opium-like compounds that cause pleasurable feelings. It also stimulates activity of dopamine, a natural chemical in the body associated with sexual arousal and pleasure.
Women are more sensitive to chocolate and experience stronger cravings for it than men. Chocolate can be particularly beneficial to women at certain times because it elevates brain levels of serotonin, a natural feel-good brain chemical. Women's serotonin levels often dip during premenstrual syndrome and menstruation; eating chocolate at these times can therefore provide a desirable mood boost.
Chocolate also contains the chemical anandamide, which binds to the same receptors in the brain as do the psychoactive constituents of cannabis. It is not clear, however, whether there is enough phenylethylamine or anandamide in chocolate to induce a pleasurable mental state. It probably depends on individual body chemistry - eating a chocolate bar may do little for my mood, but it may make you swoon.
So what am I saying? Eat lots of chocolate because it is good for you? No. The secret to a healthy diet is simply to eat a wide variety of foods in moderate amounts, spread over the four basic food groups. It is no harm at all, and is probably beneficial, to include a little chocolate in your diet as a treat. The best, from a health point of view, is low-sugar dark chocolate, because it has a higher cacao content. Chocolate is sweetened with sugar, so if you eat lots of it regularly you may feel very relaxed and romantic but will also become rather portly. Eating large amounts of chocolate has also been reported to predispose one to migraine headaches and to hives.
I heard recently that Robbie Williams turned down pots of money to become the new Milk Tray man. I'm available to have a go if Cadbury wishes to contact me.
William Reville is a senior lecturer in biochemistry and director of microscopy at University College, Cork