If you're tracking your fluoride intake, tea matters more than most people realise. The tea plant accumulates fluoride from soil, and it ends up in your cup.
How much is in it
- The World Health Organization puts dry tea at around 100 mg of fluoride per kg on average.
- A 2016 Irish study of 54 brands of black tea bags found brewed tea ranged from 1.6 to 6.1 mg/L, averaging 3.3 mg/L.
- A New York study found black tea at 0.6 to 3.3 ppm and green tea at 0.8 to 3.3 ppm. The brand mattered more than the type.
- Herbal teas are usually very low: one study found 0.08 to 0.16 mg/L.
- Compressed "brick" teas, made from older leaves, can be extremely high.
By comparison, Australian fluoridated tap water is 0.6 to 1.1 mg/L. Make tea with fluoridated water and the two add together.
Can tea cause harm?
For normal drinkers, there's no evidence of harm. But there are documented cases of skeletal fluorosis from extreme intake. In 2013 the New England Journal of Medicine reported a 47-year-old American woman with five years of bone pain who had brewed a pitcher from 100 to 150 tea bags every day for 17 years. Her symptoms improved after she stopped.
If you want less fluoride from tea
- Choose herbal teas, or younger-leaf teas over brick and budget blends.
- Brew with filtered water if you're also avoiding tap-water fluoride.
- Remember that boiling doesn't remove fluoride.