The Psychology of Chocolate

Key Points• Chocolate is made from the seeds of the tropical cacao tree

Research suggests chocolate may have• health benefits

Chocolate cravings may be a symptom of addiction

Chocolate contains the same • 'happy' chemicals found in some recreational drugs

Chocolate history

• Chocolate is made from the seeds of the tree Theobroma cacao.

• Theobroma is Greek for 'food of the gods'.

History

• The ancient Aztecs venerated the cacao tree and used its beans as a form of currency.

• They saw the tree as a source of strength and wealth and assigned their god Quetzalcoatl its guardian.

History

• The Aztecs discovered that by crushing the beans into a paste and adding spices, they could make a refreshing and nourishing drink.

• This drink would have been very bitter, unlike our chocolate drinks today.

History

• 16th century European explorers brought the drink back from their travels, added sweeter flavorings, and soon it was popular as an expensive luxury.

Making Chocolate

The First Chocolate Bars

• In the 1800s, solid chocolate became popular, with the invention of molding processes. Mechanical grinders crushed cocoa beans to a fine powder that could be heated and poured into moulds, forming shapes as it cooled.

The First Chocolate Bars

• Dutchman Coenrad Van Houten perfected the extraction of cocoa butter from cocoa beans in 1825. The beans are crushed to a paste, which is subjected to very high pressure, forming chocolate liquor and cocoa butter. The extracted butter is smoothed and treated to remove any odours.

The First Chocolate Bars

• In the 1880s, Rudolphe Lindt of Switzerland started adding extra cocoa butter during chocolate manufacture, to make it smoother and glossier. Cocoa butter melts at around 97°F, which is human body temperature. That's why chocolate melts in the mouth.

Milk chocolate

• In 1875, Swiss Daniel Peter perfected the manufacture of milk chocolate, which is sweeter and smoother than dark chocolate. Nestlé's recently-invented condensed milk was easy to mix with cocoa paste, unlike liquid milk.

Milk chocolate

• Cadbury's 'Dairy Milk', first developed in 1905, is the UK's most popular chocolate bar. Milk chocolate is now the world's best-selling variety.

Chocolate craving

• The love of chocolate goes beyond the call of sweetness. Chocolate can induce craving in a way that other sugary products like toffee or marshmallow don't. Chocolate makes us feel good, but can it really be addictive?

Chocolate craving

• All modern commercial chocolate products contain substantial amounts of sugar, a fact which may partly explain chocolate's supposed addictive properties.

Chocolate Craving

• Chocolate has a number of drug like effects.• It has caffeine, although less than coffee,

and theobromine, that is a neurostimulator that produces pleasure.

• The best chocolate for these effects is dark chocolate.

Chocolate Craving

• Dark chocolate has a stronger more intense chocolate flavor and a hint of bitterness.

• It is the bitterness that is associated with some of the good things.

Sweet tooth

• You can inherit a 'sweet tooth' from your parents. Recent research at New York University suggests there is a genetic reason why some people crave sugary foods.

Sweet tooth

• The study was based on two strains of mice, selectively bred according to whether the parents preferred sweetened or unsweetened water. The team located the gene that was different in the two groups of mice and then searched for similar genetic sequences in humans.

Sweet Tooth

• An ability to identify sweet things, and a tendency to respond to them positively, would have been an advantage for our ancestors.

• Such a genetic trait would have made prehistoric humans seek energy-rich, highly nutritional food such as fruit, while avoiding bitter-tasting poisonous plant material.

Sweet Tooth

• This ancient genetic preference is arguably less useful in the context of a modern supermarket.

Chocolate chemistry

• Like other sweet food, chocolate stimulates the release of endorphins, natural body hormones that generate feelings of pleasure and well-being.

Chocolate Chemistry

• General sweetness aside, there are various chemical elements specific to chocolate that may help to stimulate cravings. In fact, chocolate contains over 300 chemicals and it is not known how all of these affect humans.

Chocolate Chemistry

• Many women report particular chocolate cravings when pre-menstrual. This is possibly because chocolate contains magnesium, a shortage of which can exacerbate pre-menstrual tension. Similar cravings during pregnancy could indicate mild anaemia, which chocolate's iron content may help to cure.

Chocolate Chemistry

• Chocolate contains magnesium and iron, which may be part of why women, who need more of these nutrients, crave chocolate.

• Magnesium deficiencies contribute to pre-menstrual tension.

Chocolate Chemistry

• Central nervous stimulants such as caffeine are also present in small amounts, and this has a mild effect on alertness as we know from drinking coffee.

Chocolate Chemistry

• Chocolate also makes us feel good by reacting with our brains. 

Chocolate Chemistry

• Another mild stimulant present in chocolate is theobromine, which also serves to relax the smooth muscles in the linings of the lung.

Why Chocolate Makes Us Feel Good

• Several more obscure chocolate ingredients seem to act by affecting the brain's own neurotransmitter network.

• Neurotransmitters are the chemical messengers of the brain. They work by transporting electrical signals between nerve cells. These signals cause changes in the sensations and emotions that we experience.

Love drug?

• Chocolate contains a natural 'love drug'. Tryptophan is a chemical that the brain uses to make a neurotransmitter called serotonin..

Love Drug?

• High levels of serotonin can produce feelings of elation, even ecstasy - hence the name of the designer drug that also works by increasing serotonin levels

Lust drug?

• While tryptophan could be considered 'chocolate's ecstasy', another chemical called phenylethylamine has earned the nickname 'chocolate amphetamine.'

Lust Drug?

High levels of this neurotransmitter help promote feelings of attraction, excitement, giddiness and apprehension. Phenylethylamine works by stimulating the brain's pleasure centers and reaches peak levels during orgasm.

Lust Drug?

• But many scientists are skeptical that chocolate could produce mood-altering effects in this way. Chemicals like tryptophan and phenylethylamine, which are also found in many other foodstuffs, are present in chocolate only in very small quantities.

Chocolate Pot?

• The same is true of anandamide, the current favourite candidate for a psychoactive chocolate ingredient. Anandamide is a neurotransmitter that targets the same brain structures as THC, the active ingredient in cannabis. But to make a substantial impact on the brain's own natural anandamide levels, experts estimate you would need to eat several kilos of chocolate!

Chocolate Pot?

• Neuroscientist Daniele Piomelli suggests that chocolate works more indirectly to produce its 'high'. As well as anandamide itself, chocolate contains two chemicals known to slow the breakdown of anandamide. Chocolate might therefore work by prolonging the action of this natural stimulant in the brain. The animation below shows how this could work.

Chocoholism

• This type of effect is a possible scenario for the development of a physical dependency on chocolate. Current studies of psychoactive drugs show that addiction is associated with the formation and reinforcement of unusual neurotransmitter pathways in the brain.

Chocoholsim

• So it's just possible that, with every binge, your brain is being gradually 'rewired' in order to make you love chocolate more and more!

• But could chocolate be good for you?

Is Chocolate Good For You?

• Should chocolate be an essential component of a balanced diet? Back in the 17th and 18th centuries, many treatises were written extolling the medicinal virtues of chocolate and today it's a regular feature in army food rations.

Is Chocolate Good For You?

• During the Gulf War, critical equipment flown out to US forces included a specially formulated heat-stable chocolate bar. But the jury is still out on whether or not it's good for us.

Chocolate toothpaste

• Chocolate could help prevent tooth decay, according to scientists at Japan's Osaka University. The husks of the cocoa beans from which chocolate is made contain an antibacterial agent that fights plaque. These husks are usually discarded in chocolate production, but in future they could be added back in to chocolate to make it dental-friendly.

Chocolate toothpaste

• They concluded that the cavity-fighting action of cocoa bean husks isn't enough to offset decay caused by chocolate's high sugar content, however, so chocolate isn't going to replace toothpaste any time soon.

Hearty findings

• Californian scientist Professor Carl Keen and his team have suggested that chocolate might help fight heart disease. They say that it contains chemicals called flavinoids, which thin the blood, helping to prevent clotting.

Hearty findings

• Scientists have already suggested that red wine acts in this way. However, sceptics have pointed out that Keen's research is funded by confectionery maker Mars.

Good news and bad news

• Researchers at Harvard University have carried out experiments that suggest that if you eat chocolate three times a month you will live almost a year longer than those who forego such sweet temptation.

Good news and bad news

• But it's not all good news - the Harvard research also suggested that people who eat too much chocolate have a lower life expectancy. Chocolate's high fat content means that excess indulgence can contribute to obesity, leading to an increased risk of heart disease.

Good news and bad news

• It looks like the old adage of "everything in moderation" holds. But if you can't resist chocolate, at least stick to dark. It's higher in cocoa than milk chocolate and helps to increase levels of HDL, a type of cholesterol that helps prevent fat clogging up arteries.

Death by chocolate

• Dogs and other domestic animals like horses metabolise the chocolate ingredient theobromine more slowly than humans. Safe doses for us could be toxic or even lethal doses for our pets, affecting their hearts, kidneys and central nervous systems.