To the Editor:
In the January 1, 2005, issue of the Journal, we described skeletal fluorosis in an otherwise healthy American woman who consumed inordinate volumes of double-strength instant tea daily throughout her adult life.
1
Although skeletal fluorosis is rare in the United States,2
tea is fluoride rich,3
and this disorder is common in Asia where “brick” tea comprises mature leaves, twigs, and berries of the tea plant Camellia sinensis.4
Additionally, we reported that the fluoride concentrations in the drinks made from some commercial instant tea mixes exceeded US Food and Drug Administration (FDA) limits for bottled water and beverages.1
Here, I record the fluoride concentrations in brand name bottled teas. One of each preparation from a local supermarket was assayed for fluoride by the 2 previously commissioned laboratories.
Manufacturers: Lipton (Unilever Bestfoods North America, Englewood Cliffs, NJ), Nestea (Nestlé USA, Inc., Glendale, Calif), AriZona (AriZona Beverage Co., Lake Success, NY), Sweet Leaf (Sweet Leaf Tea Co., Austin, Tex), and Snapple (Snapple Beverage Corp, White Plains, NY).
1
Identical aliquots were examined blindly using “ion-specific electrode with known additions” methodology.5
Four of the 11 drinks had fluoride concentrations above the FDA’s highest limit of 2.4 parts per million (ppm) for bottled beverages (Table).TableFluoride concentrations in commercial bottled teas
| Sample | Product | Fluoride (ppm or mg/L) | |||
|---|---|---|---|---|---|
| Laboratory 1 | Laboratory 2 | Mean | |||
| 1 | Lipton | Original Iced Tea | 3.5 | 3.4 | 3.4 |
| 2 | Nestle | Iced Tea | 2.9 | 2.8 | 2.8 |
| 3 | AriZona | Diet Green Tea with Ginseng | 1.4 | 1.4 | 1.4 |
| 4 | “ | Iced Tea with Lemon Flavor | 1.7 | 1.8 | 1.7 |
| 5 | “ | No Carb Green Tea | 1.3 | 1.3 | 1.3 |
| 6 | “ | Iced Tea with Ginseng Extract | 1.8 | 1.8 | 1.8 |
| 7 | “ | Rx Stress Herbal Iced Tea | 2.3 | 2.3 | 2.3 |
| 8 | Sweet Leaf | Herbal Tea | 0.9 | 1.0 | 0.9 |
| 9 | “ | Green Tea | 3.3 | 3.1 | 3.2 |
| 10 | “ | Sweet Tea | 4.2 | 4.0 | 4.1 |
| 11 | Snapple | Iced Tea | 1.0 | 1.0 | 1.0 |
† Laboratory 1 = St. Louis Testing Laboratories, St. Louis, Mo; Laboratory 2 = Kiesel Environmental Laboratories, St. Louis, Mo.
‡ Average of the 4 determinations (duplicate in both laboratories).
Adults typically consume <0.5 mg of fluoride daily in food.
2
Water fluoridation increases intake by about 1 mg/day.2
Most is absorbed from the gastrointestinal tract with equivalent amounts entering the skeleton and urine.2
, 6
Nearly all endogenous fluoride sequesters in calcified tissues where it enhances osteoblast action, but toxicity produces brittle, dense bones.6
The skeletal half-life in adults averages 7 years, and increases with advancing age.6
Skeletal fluorosis follows prolonged consumption of well water containing fluoride concentrations >4 ppm.2
, 7
Intake of at least 10 mg of fluoride daily for 10 years seems necessary for “preclinical skeletal fluorosis” and is the “no-observed-adverse-effect level” for adults.U.S. Environmental Protection Agency: Ground Water and Drinking Water—Current Drinking Water Standards. Available at: http://www.epa.gov/safewater/mcl.html. Accessed May 13, 2005.
2
The Environmental Protection Agency stipulates a maximum contaminant level for fluoride of 4.0 ppm in drinking water, calculated from the lowest effect level for crippling skeletal fluorosis of 20 mg/day with continuous exposure for at least 20 years.2
, 7
U.S. Environmental Protection Agency: Ground Water and Drinking Water—Current Drinking Water Standards. Available at: http://www.epa.gov/safewater/mcl.html. Accessed May 13, 2005.
Tea drinking is popular in the United States and increasingly is suggested to promote health. Preference for various commercial drinks is diminishing per capita consumption of tap water
2
where the Public Health Service regulates community water fluoridation at 0.7 to 1.2 ppm, depending on average air temperature.2
, 8
Fluoride levels in tea reflect various factors, including growing region and season at harvest.4
Brewed tea reportedly contains 1 to 6 ppm, depending partly on the water source and steeping time.2
In Germany, bottled teas contain 0.03-1.79 ppm fluoride,9
but in Taiwan they average an extraordinary 25.7 ppm.3
FDA requirements for bottled water and beverages packaged in the United States stipulate against fluoride levels in excess of 1.4-2.4 ppm, depending on the annual average maximum daily air temperature where the products are sold.
10
In this one-time exploration of “ready-to-drink” teas, several exceeded the highest limit. Skeletal fluorosis seems possible, especially in hot climates or with renal compromise, from drinking excessive quantities of instant or bottled teas. Our observations support the need for better understanding of the amounts and systemic effects of fluoride in teas.References
- Skeletal fluorosis and instant tea.Am J Med. 2005; 118: 78-82
- Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. National Academy Press, Washington, DC1997: 288-313
- Fluoride concentrations in three types of commercially packed tea drinks in Taiwan.J Expo Anal Environ Epidemiol. 2003; 13: 66-73
- Brick tea fluoride as a main source of adult fluorosis.Food Chem Toxicol. 2003; 41: 535-542
- Cresceri L.S. Greenberg A.E. Eaton A.D. Standard Methods for the Examination of Water and Wastewater. 20th edn. American Public Health Association, the American Water Works Association and the Water Environment Federation, Washington, DC1998
- Skeletal fluorosis in humans.Prog Food Nutr Sci. 1986; 10: 279-314
U.S. Environmental Protection Agency: Ground Water and Drinking Water—Current Drinking Water Standards. Available at: http://www.epa.gov/safewater/mcl.html. Accessed May 13, 2005.
- Review of Fluoride. U.S. Department of Health and Human Services, Public Health Service, Washington, DC1991
- Fluoride concentration and pH of iced tea products.Caries Res. 2002; 36: 405-410
United States Food and Drug Administration. Department of Health and Human Services. Bottled Water (2003) (codified at 21 CFR §165.110).
Article Info
Footnotes
Supported by the Clark and Mildred Cox Inherited Metabolic Bone Disease Research Fund and Shriners Hospitals for Children, St. Louis, Mo.
Presented at the 27th Annual Meeting of The American Society For Bone and Mineral Research, September 23-27, 2005, Nashville, Tenn.
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Copyright
© 2006 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
