Availability of fluoride from meals given to kindergarten children in Brazil

Abstract

The aim of this study was to evaluate the amount of fluoride supplied daily in the meals given in 44 public kindergarten schools in Bauru, Brazil. In addition, the fluoride concentration of water supplies and its impact on the amount of fluoride found in the meal samples were also investigated. Meal samples and water were collected during 2 weeks (10 working days) in public kindergarten schools. Samples of meals were homogenized with known volumes of deionized water. Fluoride present in meal samples was analyzed with the ion-specific electrode (Orion 9609), after hexamethyldisilazane-facilitated diffusion. Fluoride in water samples was analyzed with the same electrode, after buffering with TISAB II. All the analyses were made in duplicate. Fluoride analyzed (mean+/-SD) was 0.50+/-0.20 microg/ml, ranging from nondetectable to 1.42 microg/ml for water samples (n=424) and 0.067+/-0.059 mg, ranging from 0.007 to 0.580 mg for meal samples (n=431). A weak but significant correlation was observed between the amount of fluoride in meals and fluoride concentration in water supplies (r=0.139, P=0.0042). Despite the seemingly small role played by school meals in the total daily fluoride intake, they can contribute to the total fluoride intake of children on a chronic basis, when in association with other fluoride products. Additionally, the impact of fluoridated public water supply on the final fluoride concentration of the school meals analyzed may be regarded as low.