University of Iowa Health Science Relations and
Nicole Nisly, MD
Associate Professor of Internal Medicine
First Published: January 2003
Last Revised: February 2003
Peer Review Status: Internally Peer Reviewed

Green tea can be more than a comforting brew.

The wind is blowing snow around outside and you're sitting comfortably in your chair, sipping a cup of hot tea, warming you from the inside out. And holding the warm mug is a bonus for your cold fingers.

Tea was discovered in China more than 4,000 years ago and today is one of the world's most popular drinks. Teas are made from the leaf of the Camellia sinesis plant and there are three types of tea--green, oolong, and black. They differ only in the duration of fermentation. Black tea is fully fermented, oolong is partially fermented, and green is not fermented at all, only steamed. Types of tea, like Ceylon and Darjeeling, refer to the region where the tea is grown. Herbal and flavored teas are an infusion of ingredients other than or in combination with Camellia sinesis.

But tea is more than a steamy, comforting brew. Evidence of green tea's health-promoting properties is becoming more wide spread, says Nicole Nisly, MD, UI Health Care physician specializing in alternative medicines at the UI Family Care Center. The Chinese have known about the medicinal benefits of green tea since ancient times, using it to treat everything from headaches to depression.

Western research is providing evidence supporting the health benefits of drinking tea, especially green tea.

"I recommend green tea regularly to my patients with cancer," says Nisly. The Journal of the National Cancer Institute has published several articles about green tea, including the results of an epidemiological study indicating that drinking green tea reduced the risk of esophageal cancer in Chinese men and women by nearly 60 percent.

There is also research indicating that the antioxidants in green tea lower total cholesterol levels as well as improve the ratio of good (HDL) cholesterol to bad (LDL) cholesterol. Green tea is loaded with catechin polyphenols, a type of photochemical with 100 times the antioxidant kick of vitamin C.

But beware, you'll have to swallow a lot of green tea to gain some of the health-promoting benefits. While there are no scientific standards set for how much green tea can be beneficial, studies touting the success of green tea report that subjects drank between three and six cups of tea daily. Green tea contains caffeine, but not as much as coffee.

Brew a good cup of tea

While a good cup of tea is as distinctive as the person drinking it, here are a few tips on how to brew a cup to get the most health benefits from green tea:

Size of tea leaves

Small loose leaf green tea is the best choice because it infuses quickly.

Loose leave or teabag

Loose leaf is best. If you use a teabag, continuously dunk the teabag in the water to increase extraction of the catechin polyphenols.

Water temperature

Boiling water promoted the extraction of catechin polyphenols.

Steeping time

Steep for two to five minutes. Catechin polyphenols content increases with steeping time.