Comparison of a dietary survey and the duplicate plate method for determining dietary fluoride ingested by young children: A pilot study

Background. Investigators have attempted to establish the diet's contribution to the total body burden of fluoride in response to a reported trend towards an increase in fluoride intake. Aim. The aim of this study was to compare the suitability of two methods to collect dietary data for fluoride intake assessment. Design. Assessments were made in 12 children using the duplicate plate and dietary diary methods following a randomized cross-over design. Foods and beverages were analysed for fluoride, and total fluoride intake per day was calculated. Results from each method were compared. Results. Mean beverage fluoride intake was estimated at 316 ± 120 and 422 ± 195 μg/day utilizing the diary and duplicate plate methods, respectively. Mean food fluoride intake was estimated at 188 ± 48 μg/day using the diary, whereas it was 130 ± 41 μg using the duplicate plate method. Total fluoride intake was 504 ± 138 and 552 ± 192 μg/day utilizing the diary and duplicate methods. Large variations in daily fluoride intake from both beverages and food were observed between and within children. Conclusions. Both methods had inherent shortcomings and sources of error. The duplicate method was more labour intensive and costly; however, the diary method required a large number of assumptions. A combination of both methods seems to be most suitable to obtain reliable data.