Fluoride Content of Infant Formula Commercially Available in Central Indiana

Abstract

BACKGROUND: Fluorides have a well-established role in dental caries prevention. Fluoride content in infant formula has raised concerns about whether it is within safe levels for the developing teeth. There is a large number of products on the market with likely varying fluoride concentrations, and these products’ fluoride content will differ depending on whether, for example, fluoridated water was used during manufacturing or reconstitution. Several studies have been published on infant formula containing fluoride and the associated risk of developing enamel fluorosis. However, few recent studies in the US have determined whether liquid or powder infant formula fall within safe/recommended levels. Purpose: This study measured the fluoride content of infant formula sold in grocery stores in central Indiana, prepared using three types of water (Purified, Nursery, and Tap) to determine if they fall within safe levels. Alternative hypotheses: There is a significant difference in the concentration of fluoride between different brands of infant formula. Material & Methods: We analyzed twenty different infant formula products sold in grocery stores in the Indianapolis, Indiana area for their fluoride content. Samples were reconstituted with Nursery water (containing approx. 1.0 ppm fluoride), Tap water (approx. 0.7 ppm fluoride) and Purified water (negligible fluoride content). A sample for the tests was taken from each preparation and the concentrations of fluoride of all samples was determined using the fluoride microdiffusion method. The statistical analysis of results was carried out using two-way ANOVA. Results: When comparing the mean (SD) fluoride concentration among the three types of infant formula reconstitution with water, tap water had significantly higher fluoride concentration mean than both Nursery water and purified water (P <.001 at α=.050 level). Nursery water also had significantly higher fluoride concentration mean than purified water (P <.001 at α=.050 level). When the three types of water were used for reconstitution of the 20 infant formula brands, the overall highest fluoride concentration mean was seen when tap water was used for reconstitution (0.950) followed by nursery water (0.789) while the least fluoride concentration was in purified water (0.102). Conclusion: Within the study's limitations, it can be concluded that apart from one formula none of the tested infant formulas sold in central Indiana grocery stores when reconstituted with purified water were found to decrease the chance of infants exceeding UL levels for both age groups but were found to increases the chance exceeding the AI levels for infants aged 0–6 months. All tested infant formulas reconstituted with nursery and tap water were found to increase the chance of infants exceeding the UL, and the AI levels for both groups resulted in increasing the chance of fluoride concentrations exceeding the recommended/safe levels. Thus, the type of water used for reconstitution rather than the type of formula appears to be the determining factor for the levels of fluoride intake associated with infant formula. Clinical Significance: With the recent increase in the utilization of infant formula, different brands with varying fluoride concentrations and the different modes of reconstitution must be evaluated to determine if their fluoride concentrations will fall within safe/recommended levels and thus increase the risk of enamel fluorosis development.