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Fluoride toxicity may be a problem for heavy tea drinkers if they drink economy brands, due to the amount of fluoride in the tea plant, drawn from the soil it grows in.

The practice of making “brick tea” (used for economy tea blends) from the trimmings of aged plants, where the leaves may be two or three years old before harvesting, allows fluoride to accumulate to high levels.

Tea Advisory Panel, London, UK

There continues to be confusion on the presence of “tannins” in tea. The phenolic compounds found in tea, including compounds called flavonoids, are often referred to as tannins.

Although tea does contain low levels of tannin-type substances, the bulk of tea’s flavonoid polyphenols aren’t tannins. They don’t function as a tanning agent – for example, where tannic acid is used for the tanning of leather. As such, the phenolic compounds present in tea should be referred to as “derived polyphenols”.

These substances include catechins, theaflavins and thearubigins. Theaflavins are responsible for the characteristic orange tint of black tea, whereas thearubigins account for the brown colour. Without derived polyphenols, tea would lack colour, its characteristic full-bodied flavour and astringent mouthfeel.

“Cross-legged sitting is comfortable because it allows the trunk to be held in an upright position with relatively little effort”

Astringency is caused through the interaction of the derived polyphenols with proteins in the saliva and mucous membranes of the mouth. If milk is added to tea, the astringency reduces because the polyphenols interact with the proteins in the milk, rather than those in the mouth.

Many foods – most notably fresh fruit – readily cause stains, and yet we never question the wisdom of eating them on those grounds.

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