The Psychology of Chocolate

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The Psychology of Chocolate
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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

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Chocolate history

• Chocolate is made from the seeds of the tree
  Theobroma cacao.
• Theobroma is Greek for 'food of the gods'.

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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.

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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.

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History

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

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Making Chocolate
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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.

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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.

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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 97F,
  which is human body temperature. That's why
  chocolate melts in the mouth.

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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.

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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.

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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?

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Chocolate craving

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

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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.

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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.

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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.

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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.

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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.

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Sweet Tooth

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

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Chocolate chemistry

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

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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.

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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.

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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.

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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.

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Chocolate Chemistry

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

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Chocolate Chemistry

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

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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.

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Love drug?

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

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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

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Lust drug?

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

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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.

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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.

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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!

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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.

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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.

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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?

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.