Fluoride

Many studies have shown that topical fluoride—direct application of typically sodium fluoride to the teeth—is safe and effective in prevention tooth decay.

Fluoridation of the public water supply is an inexpensive way of provide fluoride to large population. However, its safety and efficacy is controversial. The main problem is that while the dosage of topical fluoride can be very carefully controlled, fluoridation of the water supply does not allow adequate control of dosages resulting in little efficacy when the dosage is too low and significant risk of harm at high dosages. 

Fluoridation is not the only source of fluoride as it is present in food at widely varying levels, in toothpaste (typically 1.0 mg each brushing if swallowed), applied by dentists, etc. The maximum safe daily intake of fluoride, according to National Research Council of the US National Academies of Science is 0.334 mg/kg/day. This translates to a maximum of 13 mg for an average teenager. However, adverse effects such as fluorosis occur at much lower intakes and many other countries assert lower safe levels. In fact, most industrialized countries do not fluoridate their water.

The most common indication of excess fluoride intake is fluorosis—white spots on the teeth. This is far more common than most people realize. However, there are some much more serious side effects that, while not common, are very important.

Since fluoride is not an essential nutrient, some researchers assert it should be considered a drug and its benefit/toxicity ratio should be considered according to this much more strenuous standard. In fact, some public health researchers suggest it be considered and environmental toxin. 

Key Points

• According to an analysis done by the Fluoride Action Network, tooth decay has been decreasing in all industrialized countries with little difference between those that use fluorination and those that don’t. 

• According to the CDC 38% of teenagers have fluorosis, indicating excessive fluoride exposure. 

• According to the NRC, fluoridation of water above 2 mg/L (the supposed upper limit of safe is 4 mg/L) results in increased bone fractures, cognitive impairment and decreased thyroid function while other potential problems such as increased cancer risk have been inconsistent. 

• A meta-analysis of 27 studies in China found that with increasing levels of fluoride in the water, children suffered cognitive impairment with an average loss of 7 IQ points in the children with the highest exposure. 

Many studies have shown that topical fluoride—direct application of typically sodium fluoride to the teeth—is safe and effective in prevention tooth decay.Fluoridation of the public water supply is an inexpensive way of provide fluoride to large population. However, its safety and efficacy is controversial. The main problem is that while the dosage of topical fluoride can be very carefully controlled, fluoridation of the water supply does not allow adequate control of dosages resulting in little efficacy when the dosage is too low and significant risk of harm at high dosages. Fluoridation is not the only source of fluoride as it is present in food at widely varying levels, in toothpaste (typically 1.0 mg each brushing if swallowed), applied by dentists, etc. The maximum safe daily intake of fluoride, according to National Research Council of the US National Academies of Science is 0.334 mg/kg/day. This translates to a maximum of 13 mg for an average teenager. However, adverse effects such as fluorosis occur at much lower intakes and many other countries assert lower safe levels. In fact, most industrialized countries do not fluoridate their water.The most common indication of excess fluoride intake is fluorosis—white spots on the teeth. This is far more common than most people realize. However, there are some much more serious side effects that, while not common, are very important.Since fluoride is not an essential nutrient, some researchers assert it should be considered a drug and its benefit/toxicity ratio should be considered according to this much more strenuous standard. In fact, some public health researchers suggest it be considered and environmental toxin. Key Points• According to an analysis done by the Fluoride Action Network, tooth decay has been decreasing in all industrialized countries with little difference between those that use fluorination and those that don’t. • According to the CDC 38% of teenagers have fluorosis, indicating excessive fluoride exposure. • According to the NRC, fluoridation of water above 2 mg/L (the supposed upper limit of safe is 4 mg/L) results in increased bone fractures, cognitive impairment and decreased thyroid function while other potential problems such as increased cancer risk have been inconsistent. • A meta-analysis of 27 studies in China found that with increasing levels of fluoride in the water, children suffered cognitive impairment with an average loss of 7 IQ points in the children with the highest exposure. 

1 Peckham S, Awofeso N. Water fluoridation: a critical review of the physiological effects of ingested fluoride as a public health intervention. ScientificWorldJournal. 2014 Feb 26;2014:2930

2 http://fluoridealert.org/studies/caries01/