A Cup of Tea for Your Health

Types of Tea

First, a clarification: We tend to think of “tea” as anything that gets steeped in hot water. However, there are many different varieties of tea. Research into health benefits mainly focuses on tea that come from one source, Camellia sinensis.

Black, oolong, green and white teas all come from this particular plant, but what’s different is the parts and the processing. Black tea is made from mature, large leaves and undergoes a process which oxidizes the leaves. The process is known as fermentation, though no actual fermentation takes place. This fermentation process is stopped halfway in the making of Oolong tea. The tea is classified as being “semi-fermented” and is said to have characteristics of both green and black teas.

Green tea doesn’t undergo fermentation, so there’s no oxidation in the processing. The tea is chemically different from black tea, and therefore offers some different benefits.

White tea is similar to green because it isn’t fermented, but it incorporates young leaves and buds — which could have less caffeine and more beneficial compounds. Though there isn’t as much research done on white tea as its black and green counterparts, green and white tea blends are hitting the shelves here in North America.

The Benefits

Like chocolate and wine, tea contains a type of flavonoids called catechins. Less-processed teas like green and white are thought to have more catechins than black tea (though there is still some debate amongst experts). The catechins and other components of tea offer many perks, including:

-Catechins can reduce blood clotting and inflammation. They can also improve blood vessel function by increasing the production of nitrous oxide (which lets the vessels relax and dilate) and blocking chemicals that cause constriction.

-Numerous studies have shown that three cups of tea a day can lower your risk of developing heart disease. Some studies also point to drinking green or black tea as a way to reduce the risk of a heart attack or stroke.

-Some studies suggest that the catechins in tea can reduce the risk of certain kinds of cancer, such as lung breast or stomach cancer. However, more research is needed to determine if green tea is beneficial for therapeutic use. However, one recent study shows that it actually blocks the cancer drug bortezomib. (See The Globe and Mail for details).

-A recent study out of the University of California (supported by the Lipton Institute of Tea) found that drinking three cups of black or green tea a day reduced the risk of Ischemic stroke by 21 per cent. Further research will be required, but there is hope that tea can be used to reduce risk, especially in people who have already had a stroke.

-Green tea, and potentially white tea as well, is thought to boost the metabolism and help with weight loss by burning more calories. The latest buzz is that when combined with exercise, green tea can help reduce that tough-to-get-rid-of belly fat (the type of fat most dangerous to our health).

In addition to catechins, tea contains some zinc and folic acid, as well as manganese (which promotes healthy bones) and potassium.

-Tea is a natural source of fluoride, which the plant accumulates from the soil.

-Despite what you’ve heard, drinking tea does count towards your eight glasses of fluid a day. According to the UK Tea Council, tea doesn’t act as a diuretic — unless there’s more than 300 mg per cup or you’re particularly sensitive to the caffeine. Regular tea drinkers often build up a tolerance. However, only herbal teas still get the nod from doctors.

-The caffeine in tea, like that in coffee, may help ward off Alzheimer’s disease and long term memory loss in women.

-In order to maximize the benefits, you’ll have to take it “black”. Some research has found that adding milk can block the healthy effects of tea. (Green and white teas are typically enjoyed without milk anyway). While the results are promising, many of these claims still warrant further investigation.

People have said for centuries that drinking tea is good for you, but science may take a while to catch up. Other types of tea, like rooibos, yerba mate and herbal teas (properly known as tisanes ), don’t actually contain the tea leaf and therefore don’t have the same health benefits. However, depending on their ingredients, they offer many perks of their own.

The Cautions

The news isn’t all good. Drinking excessive amounts of tea can actually be harmful. A few studies have pointed to damage from some chemicals in tea.

For example, Oxalate could cause kidney damage and soak up important minerals in the body, like calcium. However, there’s very little of it in tea, so drinking massive amounts would be required. Some have even noted that tea bags themselves can be harmful because they contain epichlorohydrin — a known carcinogen. (In which case, loose tea dodges that risk).

There’s also some debate about the safety of the fluoride, particularly in children and others who are at risk. And while tea does have less caffeine than coffee, multiple cups still aren’t good for people who are sensitive to the chemical or who shouldn’t have caffeine due to medications or health conditions.