Time for tea
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-concerned, 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 room-temperature water (akin to "sun tea") 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.)
Copyright Conner Middelmann-Whitney. Conner is a nutritionist, health writer and cooking instructor (check out her anti-cancer cooking videos on YouTube). She is the author of Zest for Life, The Mediterranean Anti-Cancer Diet, a cancer-prevention nutrition guide and cookbook anchored in the traditional Mediterranean diet. It is available in paperback at Amazon and other online bookstores, and as an eBook on Kindle. For comments or questions, please contact her at firstname.lastname@example.org.