Text on screen — 'Reactions, Everyday Chemistry. Produced by the American Chemical Society.'
# BREEZY LOUNGE MUSIC
Title — 'The Science of Caffeine, the World's Most Popular Drug.'
NARRATOR:
Our love affair with caffeine shows absolutely no signs of slowing down.
A drawing of the molecular structure of caffeine.
NARRATOR:
Caffeine is an interesting drug because when it enters the body, it breaks up into three different yet very similar molecules. When metabolised in the liver, enzymes chisel off one of three methyl groups to form these three metabolites with three different effects on your body — theobromine, paraxanthine and theophylline. While in the brain, this caffeine party crashes adenosine receptors, blocking the normal gas, adenosine, from doing its job. Adenosine is responsible for slowing down nerve activity in our brains, giving us the cue to calm down and take a nap. Also, adenosine is responsible for regulating neurotransmitters in the brains, such as dopamine.
A drawing of the molecular structure of caffeine sits alongside the molecular structure of adenosine.
NARRATOR:
As you can see, adenosine is also quite similar to caffeine in structure, which is why caffeine binds so easily to the adenosine protein receptors. Once connected, caffeine increases the activity in neurotransmitters like dopamine, ultimately leading to heightened brain activity. Then the three metabolites perform their own specific functions. Theobromine increases oxygen and nutrient-flow to the brain Paraxanthine enhances your body's athletic performance by increasing the rate of fat breakdown to fuel muscle activity. Theophylline increases your heart rate and reinforces your ability to concentrate. And although these effects come together to produce a state of wakefulness, too much caffeine can turn sour pretty quick. At higher doses, caffeine is known to cause jitters, anxiety and just general all-round discomfort. For this reason, scientists have found that 400mg is the safest average dose of caffeine for adults.
Text on screen — '400mg (per day).'
NARRATOR:
And on a sidenote, scientists have also found that caffeine becomes toxic around 10g, which works out to be about 75 cups of cups of coffee or 180 cups of black tea. However, the lethal limit does vary widely from person to person.