The truth about caffeine: how coffee really affects our bodies

Every day, around the world, 2bn cups are consumed. But what actually happens after you swallow that first mouthful? Here is everything you need to know

Coffee. Go juice. Liquid gold. The one with all the psychoactive properties. Once used by Sufi mystics as an aid to concentration during religious rituals, it's now one of the most ubiquitous drinks on the planet: we get through about 2bn cups a day.

It's also one of the most valued and pored-over drinks. One particularly sought-after blend, Black Ivory, which is produced by encouraging elephants to digest arabica berries, retails at more than 2,000 a kilogram, while coffee-making championships attract thousands of spectators.