Dr John Weisburger drinks 8 cups of tea a day. He specifies them to be green tea. The President Emeritus for Research of American Health Foundation is now 90 years of age.
“If you already drink a cup a day, consider having two…” said Dr Jeffrey Blumberg, professor of nutrition in Tufts University. Indeed, some cohort studies in the health effects of tea conclude that even 2 cups a day makes some difference. Most studies use the range of 4~6 cups a day to study the effects on weight loss, artery health, cancer prevention, bone preservation, and other health focuses. Many indicate that the more cups of tea you drink, the more obvious the health effects. ( For specific topics and references, please refer to the respective articles in this site. )
The quantity of intake, so it seems, is proportional to how likely one is benefit from tea. However, it is rather the amount of quality tealeaves one consumes that matter, because the quantity of salutary substances in tea, such as tea polyphenols and L-theanine, is related to the quality as well as the amount of tealeaves, not how many cups of tea. Studies show that their health benefits is proportional to the natural quantity intake. The more the merrier.
In all the research papers we have read there really has been no encounter of side effects of tea, in those that have tried to measure it. Reports of adverse effects of tea have been tied with the use of instant tea mixes and low quality compressed tea in issues of fluorides. Not specific to tea, the other major concern is caffeine. Some people are more sensitive to it and pregnant women have to use it with constrains.
Therefore, the upper limits of tea consumption is rather tied to the safety amount of caffeine and fluorides your body condition allows, as we have discussed in the respective articles in this site.
As discussed in the respective post articles, let’s recap them here for quick reference:
For fluorides safety, as long as you are using finer loose leaf teas rather than those from instant mixes, regular teabags, ready-to-drinks, or low quality compressed tea etc, you are pretty safe. ( Please refer to the article on fluorides in tea )
The pregnant woman, who should avoid excessive caffeine to prevent the baby from underweight, should keep a maximum of 6 x 220 ml cups, or about 9 x 150 ml cups. That is to say she is not excessive in chocolate, cola drinks, energy drinks etc, and avoid coffee. (Please refer to the caffeine special feature)
In terms of tealeaves amount that is about 13 g of tealeaves for the pregnant woman, if basing on conventional and milder way of infusion, i.e. 1 gram of leaves to 100 ml of water. This can be doubled for the ‘average’ person, with plenty of safety bracket.
Many people who are not allergic to caffeine, or those who use tea quality naturally lower in caffeine and fluorides, they may use a lot more tea a day.
My advise is, as with a balance in the diet, it is much more beneficial to use teas from a couple of categories of tea a day, and prepare some lighter infusion, as in the USDA or FSA (UK) surveys, 1 g to 100 ml. However, try always to prepare a round or two (or more, like I do) of stronger ones, 2 g to 100 ml, for the kick of it and for some real enjoyment of tea. As long as you keep to the amount of tealeaves used each day, and the quality is not that bad, you can benefit pretty well from this Nature’s greatest gift and not worry at all.