Never shy
about jumping on a health bandwagon, industrial beverage manufacturers
have been cashing in on the benefits of green tea, which they have
formulated in a dazzling array of delectable flavors. (Ginseng and honey
anyone? Nectarine white tea? And for the cancer-conscious, green tea
with pomegranate extract, perhaps?)
Alas, these beverages have
very little nutritional value, and in terms of cancer prevention they
may actually be counter-productive. For one, this is because they are
usually sweetened with refined sugars (about 2 tablespoons of sugar per
standard 8oz/240ml glass). As is increasingly understood, sugar and the hormones
its consumption triggers—insulin and IGF-1—promote the growth and
spread of cancer cells, as well as fueling weight-gain, another cancer
risk factor.
Moreover, bottled or canned tea beverages have levels of polyphenols and antioxidant activity 10 to 100 times lower than conventionally brewed tea, experts
say. "Many of the currently available cold bottled teas sold in the U.S.
are more like diluted sugar water than something that will help protect
your health," according to
Professor Ron Dashwood of Oregon University. "The antioxidant or
polyphenol activity found in some of them may be due in large part to
the fruit additives used as flavorings, and have little to do with the
tea polyphenols."
Lastly, bisphenol-A and other estrogen-mimicking
compounds found in many plastic bottles and can linings may pose a
further risk (as I have described here and here).
If it’s a fun, refreshing, sweet-tasting beverage you’re after, bottled tea drinks may be all right occasionally.
But if you are drinking tea to lower your risk of cancer, heart
disease, osteoporosis and a whole list of other degenerative conditions,
brew your own.
Black, oolong, green and white tea come from the same Camellia sinensis
plant; white tea is the least processed and provides the largest
quantity of antioxidant and anti-cancer compounds, notably a flavonoid
by the tongue-twisting name of epigallocatechin-3-gallate (EGCG).
Tea—especially
the more widely studied green tea—is thought to have many anti-cancer
effects. For starters, it may prevent the formation of cancer cells:
Observational studies associate regular intake of green tea with lower
risk for bladder, colon, stomach, pancreatic and esophageal cancers.
The phytochemicals in green tea have also been shown
to increase the production and activity of detoxification enxymes in
humans and may enhance our ability to detoxify carcinogens. Where there
are cancerous cells present, green tea may slow their growth and spread:
it is thought to inhibit
angiogenesis (the growth of new blood vessels to nourish a tumor) and
trigger apoptosis (spontaneous self-destruction of cancer cells).
If
three or four daily cups of green tea may have cancer-protective
properties, this doesn't mean you should guzzle a gallon a day for even
greater protection; "more" is not always "better." While the science is still unclear,
excessive amounts of plant compounds like EGCG -- particularly when
taken in the form of highly concentrated supplements -- may not
necessarily be helpful, especially for people undergoing radiation therapy,
and possibly chemotherapy too. This is because green tea's antioxidants
may protect not only normal tissues, but cancerous cells too, from the
intentionally oxidative effects of the treatment.
It used to be
thought that green tea has to be drunk immediately after brewing to
obtain maximum EGCG levels. Adding lemon or lime juice to green tea,
however, helps to stabilize flavonoid levels, which means you can drink it hours later and still obtain good EGCG intake.
My
clients often tell me they don’t drink green tea because they dislike
its bitter taste. The good news is: you don’t have to drink it plain. A
little added lemon juice and honey not only makes green tea taste
fresher and less bitter; researchers have also found that this enhances the body’s uptake of EGCG’s four-fold as compared with green tea drunk plain.
Other
ways of reducing bitterness is not to brew the tea with boiling water
(keep it at 70°C to 80°C (155°F - 180°F)) and not to let it steep for
more than three minutes.
As summer approaches, here’s another
great way to make the most of tea: cold-brew it! Not only is this type
of tea milder, lower in caffeine and more energy-efficient than
hot-brewed tea; it may also have greater antioxidant benefits. In an
Italian study,
tea steeped for two hours in cold water was substantially better at
protecting cholesterol from oxidation than tea that had been brewed with
hot water.
To vary the flavors, add some chopped ginger, a sprig
of mint, or some unsweetened orange juice or cherry syrup to hot or cold
tea. Spice lovers may enjoy green tea brewed with Indian “chai” spices
and (cinnamon, ginger, allspice, cardamom, pepper) and a smidgen of
honey. (Zest for Life has three recipes for hot and cold green tea preparations, as well as chicken soup and chilled fruit soup made with green tea.)
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