Fluoride
Likelihood of deficiency within an at-risk group, not the general population.
Strength of the peer-reviewed evidence.
Food sources
Fluoridated drinking water, Tea, Seafood, Fluoride toothpaste/rinses (topical, not dietary)
Typical intake: No formal RDA; adequate intake is roughly 3–4 mg/day for adults, primarily from fluoridated water.
Upper limit: 10 mg/day for adults: much lower margin during tooth development in young children; supervise toothpaste use (pea-sized amount, spit don't swallow) to avoid excess ingestion.
Dental & oral effects of deficiency
Increased caries susceptibility
Inadequate fluoride exposure during tooth development and throughout life reduces enamel's resistance to acid demineralization, raising caries risk.
Dental & oral effects of surplus / excess
White streaks or brown mottling of enamel (dental fluorosis)
Chronic excess fluoride intake while teeth are developing (roughly before age 8) causes mottled, pitted, or discolored enamel, ranging from faint white striations in mild cases to brown staining and pitting in severe cases. This is the textbook example of an excess-intake dental effect.
General toxicity (not necessarily oral-specific)
- Dental fluorosis: Cosmetic-to-structural enamel defect from excess fluoride exposure during tooth development.
- Skeletal fluorosis (severe, chronic excess): Rare in the US; very high chronic fluoride intake can affect bone density and joint mobility.
Sources
- Position of the Academy of Nutrition and Dietetics: oral health and nutrition. Touger-Decker R, Mobley C, Academy of Nutrition and Dietetics. Journal of the Academy of Nutrition and Dietetics, 2013.
- Chronic Fluoride Toxicity: Dental Fluorosis. Denbesten P, Li W. Monographs in Oral Science, 2011.