Fluoride is a trace mineral naturally found in small amounts in a variety of foods. It is most recognized for its role in preventing and reversing dental caries and building strong teeth and bones. [1] Most fluoride is absorbed in the gut and stored in bones and teeth. Unabsorbed fluoride is excreted in urine. Children absorb fluoride more efficiently than adults, as their teeth and bones are rapidly forming.

Recommended Amounts

AI: There is not a Recommended Dietary Allowance for fluoride as nutritional requirements have not been established. However, adequate intakes (AI), or the amount assumed to ensure adequate nutrition, have been established for adults 19+ years at 4 mg a day for men and 3 mg for women. For women who are pregnant or lactating, the AI is 3 mg.

UL: The Tolerable Upper Intake Level (UL) for fluoride for all adults 19+ years of age and pregnant and lactating women is 10 mg daily; a UL is the maximum daily intake unlikely to cause harmful effects on health.

Fluoride and Health

Food Sources

Trace amounts of fluoride are found naturally in various foods, though people obtain most fluoride from fluoridated water and toothpastes. Brewed black tea and coffee naturally contain fluoride as the plants absorb the mineral in soil. Shellfish may contain fluoride that collects in their shells and muscles.

Signs of Deficiency and Toxicity


Fluoride is not considered an essential nutrient but plays an important role in dental and possibly bone health. A deficiency of fluoride can lead to dental caries and potentially bone problems. See the section on Fluoride and Health.


Infants and children who ingest more fluoride than needed can cause dental fluorosis. This condition only occurs as teeth are forming, producing permanent white spots or lines on teeth. In more severe cases, enamel may be lost and cause a brown staining of teeth; cases like these rarely occur in communities where community fluoridated water contains less than 2 mg per liter (U.S. consumers can check fluoride levels in their tap water via the Center for Disease Control and Prevention’s My Water’s Fluoride tool). [17] It is more of a cosmetic issue and not harmful to health. It can be prevented by having children brush no more than twice a day with a pea-sized amount of fluoride toothpaste, and to spit out fluoride toothpaste and mouthwashes rather than swallow. This is especially important for children younger than 6 years old, who are at increased risk of dental fluorosis, and for children younger than 2 years old, who are more likely to swallow toothpastes and mouthwashes. [17] The risk of fluorosis decreases around 8 years old when the formation of tooth enamel is complete. [11]

A true fluoride toxicity is rare but may occur from excessive fluoride in water, whether occurring naturally or added, or accidental overconsumption of fluoride supplements. Symptoms include:

  • Nausea, vomiting
  • Abdominal pain
  • Diarrhea
  • Joint pain
  • Skeletal fluorosis, or bone loss (from chronically excessive intakes)

Did You Know?

Most bottled water does not contain fluoride, as the mineral must be added. Therefore, drinking only bottled water can increase the risk of tooth decay. Include some tap water, which has been fortified with fluoride, in the diet. It can be filtered or used in tea or coffee. Carbon or charcoal water filters do not change the amount of fluoride in tap water. Learn more about nutrition and oral health.


Vitamins and Minerals

Last reviewed March 2023

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