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Fluoridation in New Zealand

Sources of fluoride


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Fluoride in the diet

The level of fluoride in the diet has been monitored throughout the world, either by measuring levels of fluoride in individual foods or complete diets, or by blood and urine studies in humans.

The fluoride content of New Zealand diets is similar to comparable diets in other countries. However, because of the uncertainty of knowing how much fluoride is actually absorbed from the diet, definitive statements cannot be made about the real contribution of dietary fluoride to the total intake (Guha-Chowdhury 1992; Pickston et al 1985).

Seafood has high levels of fluoride (eg, the bones of tinned fish may have 500 ppm fluoride), but this may not be very well absorbed (Murray et al 1991). Only about one-seventh of the fluoride in food derives from fluoridated water used in food preparation and cooking.

An estimated 75–90 percent of ingested fluoride is absorbed by the alimentary tract (NRC 1993).

Fluoride in drinking-water accounts for approximately one-quarter of the average daily intake in young children and approximately half of the total intake in adults (NHMRC 1991). The rest of the intake is from dietary sources, especially from tea, which contains fluoride in the range 1 ppm to 3 ppm (Murray et al 1991). Some heavy tea drinkers may even have intakes of 8 mg/day to 10 mg/day.
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Work on fluoride intakes from the diets of New Zealand infants and the diets of children aged 3–4 and 7–8 years suggests that fluoride ingested is similar to that from diets in other developed countries (Chowdhury 1988; Chowdhury et al 1990; Guha-Chowdhury 1992).
This work has reinforced the overseas findings that milk formula for infants should be manufactured to be low in fluoride, which is actually the case in New Zealand (PHC 1994).

New Zealand studies on adult diets have estimated fluoride ingestion as 1.8 mg fluoride/day (adult males) with a maximum of 2.7 mg fluoride/day in teenage males (Pickston et al 1985 in Pearce et al 1992).

These estimates are similar to the estimated intakes for overseas populations that are also exposed to fluoridated water (eg, range 1.2 mg/day to 2.2 mg/day for average intakes (NRC 1993)).

One study has examined the fluoride content in New Zealand teeth over the past 30 years and found that levels have not been suggestive of excessive exposure to fluoride to that expected from exposure to water fluoridated at 1 ppm fluoride (Cutress et al 1994).
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Fluoridated toothpaste

The most widely known and used topical fluorides are incorporated into toothpastes. In many countries, over 90 percent of the toothpastes marketed contain fluoride as sodium monofluorophosphate, sodium fluoride, stannous fluoride or amine fluoride. Fluoride toothpaste is an effective method of reducing dental caries. It provides an additional benefit above that of fluoridated water. In non-fluoridated areas it is the prime method of preventing decay (Murray et al 1991).


Some risk of fluorosis is associated with using both fluoride toothpaste and fluoridated water during the tooth forming years because of young children swallowing toothpaste.

Most fluoridated toothpastes on sale in New Zealand contain 1,000 ppm of fluoride. A 400 ppm fluoride toothpaste is available for use by children under six years.
It is recommended that 1,000 ppm (adult toothpaste) be used, based on the consensus of many years of research on the effectiveness of different strength toothpaste. However a smaller amount of adult toothpaste (a smear of toothpaste on a small brush) should be used for younger children. Children should also be discouraged from swallowing or eating of toothpaste.
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Where else can I get fluoride from?

Do fluoride tablets work as well as fluoridated water?