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Maren Iverson '15 Integrated Health Sciences Major

Fluoride Concentration of Teas Consumed By College Students during Fall 2014

Fluoride is added to community water sources to prevent dental caries. However, excessive fluoride intake may contribute to dental and/or skeletal fluorosis. The incidence in fluorosis is increasing due to fluoride sources in the diet and the addition of fluoride into water supplies. The optimal intake of fluoride is between 0.05 and 0.07 mg per kg body weight per day. 1 Tea (Camellia sinensis), one of the worlds most consumed beverages, can contain high levels of fluoride but it is recommended due to its many health benefits.

Purpose: To determine the concentration of fluoride in popular teas and the amount of tea consumed by the college-aged population.

Methods: An anonymous survey was distributed electronically through email after Institutional Review Board approval (n=1815). Participants (98 females and 30 males) completed a survey assessing beverage consumption. Informed consent was the first page of the survey; consent was implied by completing the survey. Survey results directed the selection of teas to analyze. Five types of tea from five brands were purchased from local grocery stores. Each tea was brewed in 240 ml of boiling water for 3 minutes in triplicate. Teas were analyzed for fluoride concentration using a fluoride ion-selective electrode. Two-way ANOVA was used to examine the effect of tea type and flavor on fluoride concentration.

Results: The mean fluoride concentration for green tea was 7.0 mg/L (SD = 2.6), black tea 4.8 mg/L (SD = 3.0), citrus tea 0.3 mg/L (SD = 0.2), fruity tea 0.3 mg/L (SD = 0.1), and floral tea 0.3 mg/L (SD = 0.1). Two-way ANOVA yielded a statistically significant interaction between the effects of tea type and flavor on fluoride concentration [F (16, 50) = 27.025, p = .000]. The fluoride concentrations were statistically different among black tea brands [F (4) = 100.768, p = .000], green tea brands [F (4) = 16.100, p = .000], and citrus tea brands [F (4) = 8.269, p = .003]. Fluoride concentrations were very low and did not differ among fruity [F (4) = 1.540, p = .264] and floral tea brands [F (4) = 4.028, p = .034]. Seventy-five percent of the college-aged population consumed 6 or less tea beverages per week, while two percent consumed 21 or more tea beverage. The most commonly consumed types of tea consumed are green (70.4%), black (59.2%), floral (46.4%), fruity (45.6%), and citrus (38.4%) (participants indicated all types of tea that they consume).

Conclusion: The fluoride concentration of tea type varies with brand with black and green teas containing the most fluoride and citrus, fruity, and floral teas containing very low fluoride. Three or more green or black tea beverages per day provides 5.11-7.45 mg/L, which exceeds 0.05-0.07 mg fluoride concentration per kg per day, the optimal intake of fluoride (assuming a 68 kg college-aged student and 12-ounce beverage). Three participants consume more than the optimal intake of fluoride from tea alone. The majority of the college-aged population is not at risk for excess fluoride intake based on tea consumption alone; however, fluoride concentrations should be listed on nutritional labels so that consumers can make informed decisions regarding their health.
1 Warren, J., Levy, S., Broffitt, B., Cavanaugh, J., Kanellis, M., & Weber-Gasparoni, K. (2009). Considerations on optimal fluorite intake using dental fluorosis and dental caries outcomes- A longitudinal study. Journal of Public Health Dentistry, 69(2), 111-115. doi: 10.1111/j.1752-7325.2008.00108.x.

Maren Iverson '15
Maren Iverson '15
Maren Iverson '15

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Fluoride Concentration of Teas Consumed By College Students during Fall 2014
Research Advisor: Amy Olson, PhD, RDN, LD