The fluoride content of infant formulas available in 1985.

The purpose of this study was to measure the fluoride content of several brands of commercially available infant formulas obtained from various geographic locations in the United States. Fluoride determinations were accomplished using a modification of the Tares microdiffusion method. Ready-to-feed infant formulas were found to contain significantly more fluoride as a group than either the concentrate or powder types of infant formulas (P < 0.001). No significant differences in fluoride concentrations were found between the concentrate and powder types of infant formulas. Soy-based infant formulas were found to contain more fluoride than the milk-based formulas for all groups tested. These differences were statistically significant for the concentrate and powder types of infant formulas (P < 0.001). It appears that fluoride concentrations in infant formulas now are controlled at lower levels than has been reported in the past. In the past, some infant formulas have been shown to contain relatively high levels of fluoride. 1 The fluoride content was noted to vary between products and for the same product purchased in different cities. This variability was explained by differences in the fluoride content of water used in processing them. Because of the relatively high fluoride concentrations found in some infant formulas, these studies suggested that infants who consumed such products living in areas with non fluoridated water would run the risk of fluorosis if given a fluoride supplement. It was recommended that children drinking infant formulas and residing in nonfluoridated areas not be given a fluoride supplement during the first 6 months of life2 More recently, reports in the literature have indicated that manufacturers of infant formulas have agreed to reduce the fluoride content of the water ~ Wiatrowski et al. 1959; Adair and Wei 1978; Tinanoff and Mueller 1978; Singer and Ophaug 1979. used in processing their products to < 0.15 ppm F. 2 Adequate documentation of such reduction does not exist in the literature. The purpose of this study was to determine the fluoride content of commercially available infant formulas obtained from various geographic locations in the United States. Methods and Materials Infant formulas tested in this project were purchased from local supermarkets in 7 cities across the United States: Minneapolis, Minnesota; Los Angeles, California; New York, New York; Largo, Florida; Dallas, Texas; Seattle, Washington; and Chapel Hill, North Carolina. A sample of all infant formulas reasonably available to the purchaser in each city was gathered for testing. Between 7 and 24 products were collected from each location. Concentrated or powdered infant formulas were reconstituted with deionized water according to the manufacturer’s recommendations before fluoride determinations were made. Assay of the deionized water consistently give a fluoride content of < 0.01 ppm F. Additionally, the samples collected in Chapel Hill were reconstituted with optimally fluoridated tap water (1.1 ppm) to determine if all of the fluoride added from the tap water could be recovered from the formulas. Ready-to-feed formulas were tested without dilution. Triplicate 1-ml (1 g) samples of each product were assayed using the microdiffusion method described by Taves as modified by Whitford and Reynolds. 3 An Orion solid-state fluoride electrode coupled with a Coming microsample calomel reference electrode was used to assay the diffused samples. Measurement error was ___ 2.58%. Intergroup means were compared statistically using the t-test with P < 0.05 regarded as significant. 2 Tinanoff et al. 1981; Feigal 1983. 3 Taves 1968; Whitford and Reynolds 1979. PEDIATRIC DENTISTRY: March 1987/Vol. 9 No. 1 33 TABLE 1. Mean Fluoride Concentrations (ppm F) of Ready-to-Feed Type Infant Formulas Chapel Hill, Largo, New York, Minneapolis, Dallas, Los Angeles, Seattle, NC FL NY MN TX CA WA Advance 0.21 + 0.002 Enfamil 0.11 + 0.000 Enfamil + Fe 0.17 + 0.005 Isomil 0.30 + 0.007 Isomil SF Nursoy Pedialyte Prosobee 0.30 + 0.011 Similac 0.19 ± 0.002 Similac + Fe 0.17 + 0.005 Similac + whey + Fe SMA + Fe 0.23 + 0.004 SMA + 1o Fe i-Soyalac Soyalac 0.28 + 0.001 0.32 ± 0.007 0.22 + 0.005 0.20 ± 0.003 0.10 + 0.003 0.19 ± 0.001 0.21 + 0.006 0.38 + 0.012 0.12 ± 0.002 0.11 0.23 0.24 0.37 0.19 ± 0.001 ± 0.001 ± 0.003 ± 0.005 ± 0.007 0.34 ± 0.008 0.15 ± 0.008 0.07 ± 0.003 0.32 ± 0.013 0.18 ± 0.003 0.34 ± 0.009 0.12 ± 0.002 0.16 ± 0.006 0.07 ± 0.001 0.21 ± 0.009 0.05 ± 0.001 0.28 ± 0.005 0.22 ± 0.007 0.15 ± 0.O08 0.06 ± 0.001 0.33 ± 0.017 0.28 ± 0.003 0.22 ± 0.009 0.20 ± 0.008 0.06 ± 0.003 0.21 ± 0.005 0.22 ± 0.005 0.21 ± 0.016 0.13 ± 0.003 0.24 ± 0.006 0.23 ± 0.002 0.26 ± 0.003 0.19 ± 0.005