Green tea and the risk of cancer in Japan

Researchers in Japan report that drinking more green tea lowers the risk of hematologic malignancies — cancers that affect blood, bone marrow, and lymph nodes.

First, the details.

  • The findings come from data from the Ohsaki National Health Insurance Cohort Study.
  • 41,761 Japanese adults answered a food frequency questionnaire survey.
  • They were followed for 9 years.

And, the results.

  • There were 157 hematologic malignancies.
  • Drinking more tea (5 vs less than 1 cup/day) was associated with a lower risk of hematologic malignancies.
  • This association was consistent regardless of gender and body mass index.

The bottom line?

The authors concluded, “Green tea consumption was associated with a lower risk of hematologic malignancies.”

A recent review of green tea and the risk of solid cancer — prostate, lung, ovarian, urinary, and oral cancer — concluded there was insufficient and conflicting evidence to give any firm recommendations regarding green tea consumption for cancer prevention.”

At best, researchers have reported only a weak association between drinking green tea the risk of breast cancer.

Some cancers affect solid organs as listed above; others affect blood and blood forming tissue, as studied by the researchers from Japan. Their preliminary research suggests that drinking green tea might reduce the risk of cancer that affect blood, bone marrow, and lymph nodes.

More research is needed here.

8/3/09 23:02 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.