Fluoride Intake of Infants in New Zealand

Abstract

Since the fluoride (F-) intake of New Zealand infants and young children is not known, a study was designed to determine and compare the F- intake of infants, aged 11 to 13 months, residing in fluoridated (F) and non-fluoridated (NF) areas. Parents of 60 infants duplicated quantitatively and qualitatively all food and drink that the infants ingested during a three-day period. The acid-diffusible F- content in the liquid homogenate was isolated by the HMDS-HCl diffusion technique (Taves, 1968) and measured by a fluoride electrode. The ionic F- in samples of breast milk was measured directly by the electrode. In the F area, the F- content of the food and drinks of 31 subjects ranged from 0.130 to 0.679 mg/kg (mean, 0.320; SD, 0.168); in the NF areas, the F- content of the food and drinks of 29 subjects ranged from 0.036 to 0.281 mg/kg (mean, 0.095; SD, 0.053). The dietary intake ranged from 0.089 to 0.549 mg F/day (0.009-0.056 mg F/kg bw) in the F area, and from 0.038 to 0.314 mg F/day (0.004-0.038 mg F/kg bw) in the NF area. Including F- from tablets and toothpastes, total intake ranged from 0.093 to 1.299 mg F/day (0.009-0.150 mg F/kg bw) and from 0.039 to 0.720 mg F/day (0.004-0.061 mg F/kg bw) in F and NF areas, respectively. The mean dietary intake of infants in the F area was about half the recommended "optimal" range; in the NF areas, the dietary intake was five to seven times less than the optimal. Sources of high fluoride intake such as soy-milk formulae and tea, however, raised the fluoride content of the diet to near optimal levels. The use of F toothpastes and tablets raised the intake to near optimal levels. The optimal intake was exceeded by one child in the F area as a result of excessive toothpaste use. It was calculated that, if a child on soy formula in the non-fluoridated areas were to ingest fluoride supplements and large amounts of toothpaste as well, the total fluoride intake of this infant could exceed optimal levels. This finding stresses the need for identification of potential sources of high fluoride intake in a child's diet before any form of fluoride supplementation is recommended.