FLUORINE is never found in its elemental gaseous forms but only in combined form. FLUORIDE is a trace element that is the ionic form of fluorine. In other words, fluorine is too reactive to be out there on its own. So it easily binds with other elements and these compounds are called fluorides.
Most of us know about fluorine and fluoride in water and toothpaste, respectively. While there may be trace amounts of fluorine in food, sea fish, cheese and tea may have larger quantities.
In the body, 96% of fluoride is in the bones and teeth. It helps inhibit or reverse the initiation and progression of tooth decay. However, it is a very delicate balance. A little bit help with tooth health and stimulates new bone formation. Too much and you cause tooth decay and blocks new bone formation.
About 80% of orally ingested flouride is absorbed in the G.I. tract. Adults retain about 50% of the absorbed fluoride and excrete the rest in the urine. Children retain about 80% of absorbed fluoride.
So you can see why you'd want a well functioning G.I. tract to keep appropriate balances of absorption and elimination.