DEVELOPMENT OF ACCURATE AND REPRESENTATIVE FOOD COMPOSITION DATA FOR THE U.S. FOOD SUPPLY
Location: Nutrient Data
Title: THE FLUORIDE CONTENT OF BREWED AND MICROWAVE BREWED BLACK TEAS
Submitted to: National Nutrient Databank Conference
Publication Type: Abstract Only
Publication Acceptance Date: March 31, 2005
Publication Date: March 31, 2005
Citation: Pehrsson, P.R., Cutrufelli, R.L., Patterson, K.K., Phillips, K., Rasor, A., Heilman, J., Perry, C., Holden, J.M. 2005. The fluoride content of brewed and microwave brewed black teas. National Nutrient Databank Conference.
Fluoride (F) intake is recognized to be important to dental and bone health. Tea leaf is a known F accumulator and may contribute significantly to individual intake. The total F concentration in brewed tea also depends on the F in the brew water, which is highly variable across the US. The USDA’s Nutrient Data Laboratory determined the fluoride content of brewed and microwaved teas, using geographically matched tap water samples, for inclusion in the USDA National Fluoride Database.
Methods and Materials:
Tap water samples were collected twice (over time) from 144 nationally representative residential locations in 72 counties, in 4 Census regions (2 residences per county). Thirty-six water composites were prepared by combining the samples from the 2 sites, from each time and from two counties, paired by closeness of location. Two brands of top-selling regular and one of decaffeinated teabags were purchased in one of the 4 locations corresponding to water sampling for each of the 36 composites. Each teabag was steeped for 4 minutes in 180 mL boiled water, in an acid-washed beaker. One regular brand was microwaved (tea bag and water together) for 1 minute, and steeped for another 30 seconds. The F content was determined by direct read using an ion-selective electrode method at University of Iowa.
The mean F content for regular brewed tea was 373 +/- 6 mcg/100 g (n=63) and for decaffeinated tea was 269 +/- 8 mcg/100 g (n=33). The F content of regular brewed tea varied by region from 355 mcg/100g in the South to 393 mcg/100 g in the Midwest; decaffeinated varied from 247 mcg/100 g in the West to 293 mcg/100 g in the Midwest. The overall mean for microwaved regular tea, lower than regular brew, was 322 +/- 5 mcg/100 g (n=36). No significant regional differences were shown; values ranged from 309 mcg/100 g in the Northeast to 319 mcg/100 g in the Midwest. In all cases, prepared tea using water from the Midwest had the highest F values. The mean F content of the brewed teas was 4-5 times higher than the national mean of the tap water, analyzed separately
(71 +/- 3 mcg/100g).
These data are the first nationally representative fluoride values for brewed teas, and will provide valuable information to the dental and medical research community in assessment of fluoride intake and impact on the health of bones and teeth. Supported by NIH Agreement Y3-HV-8839 with the National Institute of Dental and Craniofacial Research and the National Heart, Lung, and Blood Institute.