The kidney then begins to remove the excess acid. As the plasma is filtered, acid anions enter the urine. In the kidney tubules, hydrogen ion is secreted. For each hydrogen ion that enters the urine, a sodium ion and a bicarbonate ion are put back into the plasma. In this way, acid is eliminated from the body.
Fruits are the normal source of alkali in the diet.
They contain the potassium salts of weak organic acids. When the anions are metabolized to CO2 and removed from the body, alkaline potassium bicarbonate and sodium bicarbonate remain. Metabolic alkalosis may be found in vegetarians and fad dieters who are ingesting a low-protein, high fruit diet. A more efficient way to get alkali into the body is to consume sodium bicarbonate. This common heartburn remedy is probably the most common cause of symptomatic metabolic alkalosis.