If you are a huge fan of black tea, you may be consuming more fluoride than is healthful. Researchers at the Medical College of Georgia found that individuals who drink large amounts of black tea may be getting much higher concentrations of fluoride than previously believed.
Dr. Gary Whitford, Regents Professor of oral biology in the School of Dentistry, notes that the increased risk appears to be associated with people who drink one or more gallons of black tea daily for a prolonged period of time. Previous studies have indicated that black tea contains 1 to 5 milligrams of fluoride per liter, but new research indicates that one liter may contain as much as 9 milligrams. People who ingest about 20 milligrams daily for more than 10 years face a significant risk to bone health.
The Fluoride Action Network website notes several other risks associated with ingestion of fluoride. According to the National Research Council (NRC), animal studies have shown that fluoride can damage the brain, resulting in dementia-like effects in mice at the same concentration used to fluoridate water (1 ppm). Studies in humans have shown that 1.8 ppm in children can have a negative impact on IQ.
The NRC also notes that fluoride in drinking water may reduce thyroid function in people who have low iodine intake. Individuals who have kidney disease are highly susceptible to fluoride toxicity, largely because they have a reduced ability to eliminate it from the body. Therefore the toxin can accumulate in the bones and cause or exacerbate a painful bone disease called renal osteodystrophy.
Fluoride is added to drinking water to help prevent dental cavities, and the average person gets about 2 to 3 milligrams daily from water as well as toothpaste and food. Thus Whitford points out that “the additional fluoride from drinking two to four cups of tea a day won’t harm anyone; it’s the very heavy tea drinkers who could get in trouble.”
Whitford discovered that the method used to identify the levels of fluoride in black tea was not accurate because it does not account for the amount that combines with aluminum to form aluminum fluoride, which is not detectable using the conventional testing method. Tea leaves accumulate large concentrations of fluoride and aluminum, and when the teas are brewed, some of these minerals leach into the beverage.
Whitford used another testing method called diffusion, which breaks the bond between aluminum and fluoride. This allows all the fluoride in tea samples to be extracted and measured. When he used this approach using seven brands of black tea purchased in stores, he found that the amount of fluoride was 1.4 to 3.3 times greater than that detected using the traditional method.
Black tea is an excellent source of antioxidants, which provide many health benefits. Studies show black tea is good for your heart, can reduce the risk of clogged arteries, help boost the immune system and fight viruses, reduce the risk of cancer, assist with weight loss, and lower cholesterol levels.
Most people should not encounter any health risks associated with fluoride from drinking moderate amounts of black tea. Individuals who are concerned about the amount of fluoride they may be ingesting from their drinking water or from other sources (e.g., certain foods, wine, seafood, toothpaste) can get more information from the “The Fluoride Glut” at the Fluoride Action Network.