Fluoride content of milk-based powdered formula in HoChiMinh City, Vietnam

The prevalence of enamel fluorosis has increased in children in HoChiMinh City after the implementation of water fluoridation. Recent studies in HoChiMinh City have implicated milk-based powdered formula, reconstituted with optimally fluoridated city water, as a risk factor for enamel fluorosis of young children. Objectives: The objective of this study was to determine the fluoride content of un-reconstituted milk-based powdered formula commonly used in HoChiMinh City, Vietnam. Methods: The study randomly selected 81 milk-based infant powdered formula products from 27 different brands maketed in HoChiMinh City to measure fluoride content. The samples were dissolved in de-ionized water and analyzed for fluoride concentration. Free fluoride was determined by direct measurement using an ion-selective electrode and total fluoride content was determined using a modified microdiffusion method. Results: The mean free fluoride concentration in infant formula was 0.017 ppm (range 0.0058-0.0639 ppm) and the mean total fluoride content was 0.102 ppm (range 0.045-0.224 ppp). The total fluoride content was statistically significantly higher than the free fluoride content (p < 0.001). The local infant milk formula products had lower fluoride content than imported products (p < 0.001). Conclusions: Local and imported milk products have differences in fluoride content. Parents should be educated about these differences.