Fluoride occurs naturally in the body as calcium fluoride. Calcium fluoride is mostly found in the bones and teeth.

Small amounts of fluoride help reduce tooth decay. Fluoridation of tap water helps reduce cavities in children by 50 - 60%. Fluorides also help maintain bone structure. Low doses of fluoride salts may be used to treat conditions that cause faster-than-normal bone loss, such as menopause.

Fluoridated water, and food prepared in fluoridated water, contains fluoride. Natural sodium fluoride is in the ocean, so most seafood contains fluoride. Tea and gelatin also contain fluoride.

Fluoride deficiency may appear in the form of increased cavities, and weak bones and teeth.

When there is a high amount of fluoride in the drinking water, a problem called chronic dental fluorosis may occur. The tooth enamel becomes dull and pitted. If the water contains over 2.5 parts per million of fluoride, the teeth will stain dark brown. Although this is unsightly, such teeth rarely have any cavities.

In addition, high fluoride intake (20 - 80 milligrams per day) over a period of many years may cause skeletal fluorosis (chalky, brittle bones).

There are no official recommended dietary allowances for fluoride. Here are the estimated safe amounts:

• Infants
  • 0 - 6 months -- 0.1 - 0.5 milligrams
  • 6 months to 1 year -- 0.2 - 1.0 milligrams
• Children
  • 1 - 3 years -- 0.5 - 1.5 milligrams
  • 4 - 6 years -- 1.0 - 2.5 milligrams
  • 7 - 10 years -- 1.5 - 2.5 milligrams
• Adolescents (11+ years) -- 1.5 - 2.5 milligrams
• Adults -- 1.5 - 4.0 milligrams