Fluorides in Tea: Good or Bad?
Zang Cha bricks 藏茶茶磚, new and old. Zang Cha is a dark tea commonly consumed by the Tibetan people. Notice a broken piece from an older brick on top: how bits of leaf stalks and older leaves are used for the product.
What about fluorides in tea?
Lastly, I have to discuss fluorides in tea. In the 1990’s much was discussed about widespread fluorosis problems in Tibetan children. An investigation was made and it was found out (6) that the brick tea that is an essential part of the Tibetan diet had a fluoride content that is 200 ~300 times that of normal green tea. The researchers found that Han children, who drank green tea rather than brick tea, and who lived in the same area as the Tibetan children, did not have the problem. In 2005 in the US, a lady who habitually drank 4 to 7 liters of ice tea from instant mixes contracted osteoporosis. Brick tea, teabags, instant tea mixes and decaffeinated teas are generally higher in fluoride contents (7).
The older the tea leaf, the more the fluorides
The fact is, the tea tree is a sink for fluorides in the soil. As the tealeaf grows, its fluoride content gradually increases. In the case of Tibetan brick tea, and other irregular quality compressed teas, old leaves, stalks and even twigs are used to make the tea. This is even worst for most tea mixes, teabags, and ready-to-drinks, which materials are usually from the pruning collected from tea plantations during off seasons of over-growns. The resultant fluoride content is always higher than even the lowest grade whole leaf plucks.
The tea plant is a sink for the fluorides from the soil. The older the part of the tea plant, the more fluorides it contains
Fluoride is a reverse tea quality indicator
Fluoride content in tea is actually a reverse quality marker: the increase of fluoride is proportional to the decrease of amino acids and flavonoids (8). Amino acid is an important taste contributive factor, while flavonols are heath contributing substances, some positive to taste as well. Finer teas, therefore, are lower in fluoride contents than lower grade products.
Medical specialists agree. In a research by the Medical University of Gdańsk in Poland in 2007 (9), where a few tea categories and qualities were analyzed for their fluoride contents, it was concluded that drinking better tea was important to protect people from excessive exposure to fluorides. Contrary to popular notions, teas from China consistently have less fluoride contents than those from other locations. Take black tea for instance, amongst the samples in the study, Yunnan Gold (aka Dianhong), a black tea from the southwestern Chinese province, contains 0.32 mg/liter (10) as compared to the next best, Maloon, a leaf tea from Nepal, which contains 0.51 mg/liter. Other samples range from 78% (a Darjeeling leaf tea) to more than 1300% (i.e. 4.54 mg/l, from an African granulated black tea) over that of the Yunnan Gold (Dianhong).
Least fluorides: White tea
White teas, which on average have the least fluorides in this report, contain an average of 0.44 mg/liter (11) and are less than the average of those in greens, oolongs and pu’er, which are all lower than the average of the black teas. The lower grade products that were in the black tea sample selections have generally raised the average fluoride content in this category. However, I have to say that there are far more black and green teas in their selections than others and the quality they have used are average to lower grade mass market products. As is the case in the studies of other aspects of tea, there is a need for comprehensive selections for a truly representational cross-section of quality and categories.
