It used to be that tea was just a nice way to end the day or soothe a reeling tummy. Now, researchers are investigating tea as an emerging means of disease prevention. Here's what the science shows.
Tea is a calorie-free drink that's soothing for most- whether hot or cold. But can tea really help improve health? We pored through the research to put your cup into perspective.
Science Says…
Sorting through research on tea and health is a little like reading tea leaves: Much of it is murky and a lot is up for interpretation. A decade ago, the FDA called laboratory studies linking tea to decreased risk for various cancers "intriguing." But when asked to review a health claim linking green tea to reduced cancer, the FDA shot it down, citing "weak" and "limited" research. (June 2005) "There are a lot of studies on cancer and tea consumption that are interesting but very mixed," says Jeffrey Blumberg, PhD, director of the Antioxidants Research Lab with the USDA Human Nutrition Research Center on Aging and a professor at Tufts University in Boston. "Evidence of tea's potential health properties has never been weighed by the FDA."
As with cancer studies, research on heart disease risk and tea provides a mix of real-world analysis (observational studies of large population groups) and controlled tests (clinical trials in small groups of people showing a true cause-and-effect relationship) but all of it is new and preliminary. "The body of evidence linking tea with heart health is just emerging," says Blumberg. Observational studies suggest tea drinking may possibly reduce risk of heart disease in healthy people as well as in those who've already had a heart attack. In clinical studies, tea is just emerging as a drink that may help lower cholesterol levels or improve blood vessel health. (Researchers believe that polyphenols, an active principle in tea, may be responsible for these outcomes.) Still, stresses Blumberg, this doesn't mean the research is definitive. Other potential health claims linking tea drinking to weight loss, reduced incidents of osteoporosis, Alzheimer's disease, and cavities are not as persuasive. "These could be promising areas for research but they aren't ready for prime time," says Blumberg, who believes the research is insufficient.
The Black, White, and Green of It
Black tea, white tea, green tea, oolong-is there a difference? Blumberg says studies don't point to any specific tea variety as being potentially more healthful than another. Not surprising, since teas come from the same plant,
Camellia sinensis. It's the place the plant is grown, the season, the specific leaves or buds that are selected, and the processing that are different. Even less is known about tisanes and herbal teas, which are not actually from the tea plant, but made from combinations of herbs, flowers, and other plants. "I like to choose different fruits and vegetables, and I also like to choose different teas for variety and fun in my diet," says Blumberg.
