Where does sugar come from, and where does it go when we eat it?

In numbers

• C₁₂H₂₂O₁₁table sugar: a molecule of 45 atoms
• 1801the first beet-sugar factory

In five stops

1. 1

   Where were its atoms born?

   Sucrose's formula is C₁₂H₂₂O₁₁: 12 carbon, 22 hydrogen and 11 oxygen atoms. The hydrogen atoms are left over from the Big Bang; the carbon and oxygen formed inside stars.

2. 2

   How did nature prepare it?

   Sugar cane and sugar beet make glucose and fructose by photosynthesis, join them together and store them as sucrose: cane in its stem, beet in its root. The plant stores this sugar for its own growth; we take it from the plant.

3. 3

   What did people do?

   Sugar cane was first domesticated in New Guinea, and for a long time people simply chewed the cane. Making sugar from cane was first learned in the Indian subcontinent. In 1747 the German chemist Andreas Marggraf showed that beet contains the same sugar; the first beet-sugar factory opened in 1801. Today beet is sliced, its sugar is drawn out with hot water, and the syrup is filtered, thickened and crystallised. Türkiye is one of the world's leading sugar-beet producers.

4. 4

   What happens when we use it?

   During digestion, sucrose splits into glucose and fructose and passes into the blood. Cells burn the glucose with oxygen to make energy. Sugar left in the mouth feeds bacteria that make acid, which wears away tooth enamel; that's why we brush our teeth.

5. 5

   Where does it go next?

   The carbon atoms of burned sugar leave in our breath as carbon dioxide, and the hydrogen atoms leave as water. The carbon dioxide returned to the air may one day enter another plant's leaf and become part of a new sugar molecule.