The liver has many digestive and storage functions. One of these is the production of bile, a solution which emulsifies fats and may assist in changing the acidic conditions of the stomach into the neutral pH of the intestine). The liver is also responsible in some species for the storage of fats, blood sugar, and vitamins A and D. Before it was possible to synthetically create vitamins A and D, sharks were caught for their livers which have high concentrations of these vitamins.