What does carbonic acid do to your body?
Carbonic acid is a carbon containing acid. It can also be carbon dioxide in water. Carbon dioxide dissolved in water is in equilibrium with carbonic acid, a state in which a chemical reaction proceeds at the same rate as its reverse reaction.
Humans have an enzyme called carbonic anhydrase, these enzymes live in our red blood cells and the zinc in these enzymes is used to rapidly convert carbon dioxide and water into carbonic acid, protons and bicarbonate ions.
The equilibrium between carbon dioxide and carbonic acid is important for controlling the acidity of body fluids. Carbonic anhydrase catalyzes the conversion between the two.
Too much acid and your bones and other body parts would slowly dissolve, the enzsyme carbonic anhydrase saves you from this. Many pops have a high carbonic acid level, like Coke.
Not enough acid could be harmful as well, our bodies like to have a nice middle ground to work with.