The New Complete Book of Food



generally 1 ppm fluoride. The USDA estimates that a six-ounce cup of tea prepared with tap
water may provide 663 mcg fluoride.
Like coffee and chocolate, tea contains the methylxanthine stimulants, caffeine,
theophylline, and theobromine. (Coffee has more caffeine; tea has more theophylline; and
chocolate has more theobromine.) The amount of caffeine in the tea depends on how it’s
made: Tea brewed from loose leaves almost always has more caffeine than tea made from
tea bags or instant tea.

Caffeine and Fluoride Content of Brewed Teas

Tea Caffeine (mg/8-oz. cup) Fluoride (mg/8-oz. cup)

White 15 (na)

Green 20 0.3–0.4

Black 40 0.2–0.5

Oolong 30 0.1–0.2

Decaffeinated 2 (na)

Coffee (5-oz. cup) 40–170* (na)

* Depends on brewing method

Sources: Stash Tea Company. “Caffeine Information on Tea.” Available online. UR L:

http://www.stashtea.com/caffeine.htm. Linus Pauling Institute, Oregon State University.

“Bioactive Compounds in Tea.” Available online. UR L: http://lpi.oregonstate.edu/

infocenter/phytochemicals/tea/#components.

Tea leaves are also rich in flavonoids, naturally occurring chemical compounds credited
with tea’s ability to lower cholesterol, reduce the risk of some kinds of cancer, and protect
the teeth from cavity-causing bacteria. Fresh tea leaves are rich in flavonoids called cat-
echins, but processing the leaves to make black and green teas releases enzymes that enable
individual catechins to join with others, forming new flavor and coloring agents called
polyphenols (poly means many) that give flavor and color to black and green teas. The length
of time tea leaves are left to dry before processing affects the rate at which their catechins
are converted to polyphenols. For example, white teas have fewer polyphenols than green
teas, which have fewer than oolong, which has fewer than black teas. As a result, nutrition
researchers at the Linus Pauling Institute at Oregon State University report that the catechin
content of white tea is three times that of green tea, with black tea a distant third. (See
below, Medical uses and/or benefits.)
Finally, tea leaves also contain antinutrient enzymes that can split the thiamin (vita-
min B 1 ) molecule so that it is no longer nutritionally useful. This is not generally considered
a problem for healthy people who eat a balanced diet and consume normal amounts of tea,
but it might trigger a thiamin deficiency if you drink a lot of tea and your diet is marginal in
thiamin. The tannins in tea are also potential antinutrients that bind calcium and iron into
insoluble compounds your body cannot absorb. According to the National Research Council

Tea