by Lori Bricker, MS, RD
A customer recently asked me this question: “One of my primary intentions in drinking green tea is the healthy benefits of EGCG/catechins. To that end, have the various teas been tested and what green teas that you carry are highest in catechins?”
Here is my answer:
We have not had any of our teas tested due to the expense of such a project.
Unfortunately, tea research rarely investigates catechin content of various specific types of tea. Typically, they only say “green tea,” which isn’t very helpful, or they test grocery store brands which are often blends.
The studies that have been done usually find that catechin content varies widely among their samples, but I have not seen any consistent data to suggest that one type of tea is always particularly high.
To give you an idea of the number of possible confounding factors, here is a quotation from one such study:
“The results of this study show that the variety, growing environment, manufacturing conditions, and grade (particle size) of the tea leaves each influence the tea leaf and final infusion compositions. In addition, the composition of the tea infusion was shown to be influenced by whether the tea was contained in a teabag and, if so, the size and material of construction of the bag. Finally, the preparation method, including the amounts of tea and water used, infusion time, and amount of agitation, was shown to be a major determinant of the component concentrations of tea beverages as consumed.” — Factors affecting the caffeine and polyphenol contents of black and green tea infusions. J Agric Food Chem. 2001 Nov;49(11):5340-7.
So even if we did have our tea tested on a regular basis, it is almost impossible to say for any given cup what the final concentration of catechins would be. I think it is likely that fresh tea from any reputable vendor should have a respectable amount of catechins, although it will vary. Tea that has been allowed to go stale will certainly be lower in catechins, but it should be noted that this is not so much a factor of the tea’s age as it is the storage method. When brewing tea, one may have to compromise between taste and catechin content since hotter water and longer brew times will extract more catechins (and caffeine), but this can lead to a bitter tasting tea.
As a dietitian, I generally suggest people find a tea they like and drink reasonable quantities of it, brewed however they like best. Keep in mind that fruits and vegetables are also excellent sources of catechins and other polyphenols (and even more other micronutrients) that are valuable to health.