It comes down to the numbers, says Dr. Rui Hai Liu, a professor in the Department of Food Science at Cornell University. "There's just not enough data to recommend any direct health benefits for humans," he explains. For instance, tea does contain chemical compounds called polyphenols — antioxidants that have been found to block enzymes that cause cancer. However, these results have been apparent only in animals, Liu adds, not yet in humans.
Even if the benefits of the brew aren't 100% conclusive, hardcore tea-lievers are quick to list the drink's health benefits. That's why we asked San Francisco's resident tea guru, Uncle Gee, owner of Vital Tea Leaf, to also give the lowdown on the five common types of tea.
Minimally oxidized and rich in a cancer-fighting compound called catechins, green tea may protect against heart-related illnesses, gastric, pancreatic, bladder, and ovarian cancers — and even cavities, according to the Mayo Clinic. On top of that, a study from the Linus Pauling Institute at Oregon State University suggests green tea can even help strengthen the immune system. Gee also fully believes in its immune-boosting effects. In fact, the 82-year-old tea importer and educator drinks four glasses a day. (Notably, Dr. Liu drinks 10-15 cups a day.)
Perk up, coffee lovers, because your daily dose of caffeine is here. Fully oxidized or crushed, black tea contains the highest levels of caffeine (14-61 mg per 8 oz) of all teas. Earl Greys and English Breakfasts are full of health-helping flavonoids, which serve as powerful anti-aging and disease-preventing antioxidants. In a recent study, researchers at the University of Western Australia found drinking black tea may even help lower blood pressure.
Oolong, a hybrid tea, is semi-fermented and processed to get the best qualities of both unoxidized green tea and oxidized black tea. "Oolong has the perfect balance of antioxidants and caffeine, which is great for coffee drinkers with high blood pressure," says Gee.
Because white tea leaves and buds are unfermented, they contain the highest amounts of antioxidants. That means a cup a day may help with skin rejuvenation and may even assist individuals with breast, colon, and prostate cancer, says Gee.
Non-caffeine drinkers, take note: Herbal teas can be infused with anything from plants to fruits to spices. However, the health benefits may be less apparent. For example, in a March 2011 study, scientists found no evidence that chamomile has the soothing effect it's often claimed to have, according to Science Daily. On the other hand, in clinical trials, scientists found hibiscus tea lowered blood pressure in a group of pre-hypertensive and mildly hypertensive adults. Basically, the health benefits will depend on the type of infusion — not all are created the same.
How To Drink It
Although tea bags are convenient, the filter lessens the potency of the active compounds, says Gee. Many prepackaged and commercial brands overprocess and overgrind their leaves. Instead, use a French press or tea ball or strainer to efficiently infuse your water. Another great tip? After boiling water, wait five to 10 minutes to let it cool before adding your loose leaves or buds. This will prevent the leaves from burning and prevent those antioxidant agents from being neutralized in the process.
So, while tea might not be a cure-all, this is one daily habit we're willing to embrace.
OXO Twisting Tea Ball, $9.95, available at Williams-Sonoma.