Tea – an everyday, common drink associated with health and peace. However, a recent scientific analysis shows that in every cup of tea there may be an ingredient whose excess is detrimental to health. We are talking about fluoride – an element that strengthens teeth, but in too large an amount leads to fluorosis and even kidney or skeletal damage.
A team of scientists from Wrocław analysed 30 studies from recent years that looked at the fluoride content of tea. As it turned out, its levels can vary widely – from trace amounts to concentrations exceeding 11 mg per litre. This is more than 250% of the daily recommended intake for adults.
The fluoride content of an infusion is a resultant of many factors: the type and form of tea, the brewing method, and even the quality of the water, explains Professor Maciej Dobrzyński of the Medical University of Wrocław. – Just one cup (approx. 250 ml) can provide as much as 1.5 mg of fluoride, which, with several cups a day, brings us close to the upper limit of the norm.
Fluoride is a micronutrient that the body needs, but excess is toxic. In countries where tea drinking is part of everyday culture – such as Tibet – cases of fluorosis of teeth and bones have been reported. That is why the researchers from Wrocław decided to take a closer look at how we brew and drink tea.
How to drink tea sensibly? Practical recommendations
The team of researchers identified five main principles that can help minimise the risk of excessive fluoride intake from tea:
Choose the right kind of tea. Black and green teas contain the most fluoride – especially the granulated or bagged versions. Herbal, white and Pu-erh teas are definitely safer, preferably in leaf form.
Avoid “economy” teas. These are blends of teas originating from India, China and Sri Lanka. According to research, their consumption of as little as one litre can exceed the daily safe dose of fluoride.
Pay attention to the form of the tea. Powdered and bagged teas have a larger surface area in contact with water, which makes it easier to release fluoride. In addition, they often use older leaves – and these accumulate fluoride throughout the life of the plant.
Brew briefly and not with boiling water. The longer the brewing time and the higher the temperature, the more fluoride goes into the infusion. Scientists recommend that brewing time should not exceed 5 minutes. Interestingly, the most fluoride is released at the beginning – after about 20 minutes, the concentration stops increasing. Subsequent infusion of the same leaves produces an infusion with less fluoride.
Pay attention to the water. If the tap water contains a lot of fluoride, the level of fluoride in the tea will also be higher. Hard water (rich in calcium), on the other hand, can partially reduce the release of fluoride.
Should manufacturers provide information on fluoride content?
According to the researchers – definitely yes. “The variability of fluoride concentrations in teas is enormous. A consumer without specialised knowledge is not able to assess the risk on his or her own,” says Agata Malyszek, M.Sc., from the Wrocław University of Life Sciences. – Marking the fluoride content on package labels, as well as information on caffeine, would allow more informed decisions.
The researchers admit that these labels would be indicative, as the final concentration in the brew is influenced by many factors – from brewing time to water hardness. Nonetheless, such a practice could increase consumer awareness and lead them to choose their tea more responsibly.
Tea – in moderation and with awareness
The study’s conclusions are not meant to scare. They are about a sensible approach to the daily ritual of drinking tea. Conscious choice of type, form and preparation can have a real impact on health – especially for heavy drinkers, children, pregnant women and people with kidney disease.
As Professor Dobrzynski concludes: It is the consumer who influences what kind of tea he chooses and how he brews it. These everyday decisions can help reduce excess fluoride – without giving up their favourite beverage.
This material is based on an article:
Applied Sciences – Identification of Factors Influencing Fluoride Content in Tea Infusions: A Systematic Review Authors: Agata Małyszek, Sylwia Kiryk, Julia Kensy , Agnieszka Kotela, Mateusz Michalak, Jan Kiryk, Maciej Janeczek , Jacek Matys, Maciej Dobrzyński
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