Impact of water fluoride concentration on the fluoride content of infant foods and drinks requiring preparation with liquids before feeding

Objectives: To measure the fluoride (F) content of infant foods and drinks requiring reconstitution with liquids prior to consumption and to determine the impact of water F concentration on their F content, as consumed, by measuring F content before and after preparation. Methods: In total, 58 infant powdered formula milks, dry foods and concentrated drinks were prepared with deionized water (<0.02 ppm F) nonfluoridated (0.13 ppm F) and fluoridated (0.90 ppmF) water. The F concentrations of drink samples were measured directly using a fluoride-ion-selective electrode after addition of TISAB III, and food samples and formula milks measured indirectly by an acid diffusion method. Results: The overall range of F concentrations of all the nonreconstituted samples, in their prepreparation dry or concentrated forms, was from 0.06 to 2.99 μg/g with the highest F concentration for foods found in the dry 'savoury meals' (a combination of vegetables and chicken or cheese or rice) group. However, when the samples were reconstituted with nonfluoridated water, the mean F concentrations of prepared 'concentrated juices', 'pasta and rice', 'breakfast cereals', 'savoury meals' and 'powdered infant formula milks' were 0.38, 0.26, 0.18, 0.16 and 0.15 μg/g, respectively. The corresponding mean F concentrations were 0.97, 1.21, 0.86, 0.74 and 0.91 μg/g, respectively, when the same samples were prepared with fluoridated water. Conclusion: Although some nonreconstituted infant foods/drinks showed a high F concentration in their dry or concentrated forms, the concentration of F in prepared foods/drinks primarily reflected the F concentration of liquid used for their preparation. Some infant foods/drinks, when reconstituted with fluoridated water, may result in a F intake in infants above the suggested optimum range (0.05-0.07 mg F/kg body weight) and therefore may put infants at risk of developing dental fluorosis. Further research is necessary to determine the actual F intake of infants living in fluoridated and nonfluoridated communities using reconstituted infant foods and drinks.