Green tea lowers blood cancer risk

Drinking about 5 cups of green tea a day may lower your risk of developing certain blood cancers.

Drinking green tea has been associated with lower risk of dying and heart disease deaths. Several biologic studies have reported that green tea constituents have antitumor effects on hematologic malignancies. However, the effects in humans are uncertain. To explore the association between green tea consumption and risk of blood cancer, researchers identified 19,749 men and 22,012 women from Japan, aged between 40 and 80 years, with no previous history of cancer. The researchers gathered information on the diets and green tea drinking habits of participants and followed them for development of blood and lymphoid system (a major component of the body's immune system) cancers. The researchers also took into consideration factors like age, gender, education, smoking status and history, alcohol use, and fish and soybean consumption.

During 9 years of follow up, 157 blood, bone marrow, and lymph system cancers developed in the study group. It was found that the overall risk for blood cancers was 42 percent lower among study participants who drank 5 or more, versus 1 or fewer, cups of green tea daily. Drinking 5 or more cups of green tea daily was also associated with 48 percent lower risk for lymphoid system cancers.

The researchers also observed reduced risk for blood-related cancers among obese study participants, who are considered to have higher risk of these cancers.

Further studies are needed to confirm the health benefits of drinking green tea, and to determine whether daily consumption might prevent certain other cancers.