Feb. 15, 2005 (Bloomberg) -- Drinking
coffee reduces the risk of developing liver cancer, though the
beverage doesn't decrease chances of getting colorectal cancer, two
studies found.
Japanese researchers studying more
than 90,000 middle-aged men and women found that the risk of liver
cancer for people who almost never drank coffee was about 547 cases
per 100,000 people. The risk among those who drank coffee daily was
about 215 cases per 100,000, according to the study.
A separate study from Brigham and
Women's Hospital in Boston tracked about 134,000 men and women and
found coffee had no significant effect on their risk of colorectal
cancer. Both studies are to be published in the Feb. 16 edition of
the Journal of the National Cancer Institute.
Karen Michels, an associate
professor at Brigham and Women's who led the hospital's study, said
researchers are just starting to get hard evidence on coffee's
effects on various cancers. The medical community is interested in
the findings because coffee- drinking is a widespread behavior that
people can change, she said.
``You can study the genetic
predispositions to different cancers, and it's interesting, but
there's nothing can you do about it,'' Michels said in an interview.
``Coffee-drinking is a behavior, something you can modify.''
About 49 percent of Americans 18
years and older drink coffee daily, according to the National Coffee
Association, based in New York. Japanese individuals drink an
average of 10 cups of coffee a week, according to the study.
The Boston study specified that
participants drank coffee with caffeine. The Japanese study didn't
distinguish which type of coffee was consumed, though its authors
said decaffeinated coffee is rarely drunk in Japan.
Inhibits Growths
Coffee contains a substance called
chlorogenic acid, which has been shown to inhibit cancerous growths
on the liver, according to the study led by Manami Inoue of the
National Cancer Center in Tokyo.
Coffee with caffeine also was
thought to help prevent colorectal cancer because it increases bowel
function, which decreases damage to parts of the intestinal tract,
Michels said.
``To our surprise, our study did not
confirm that,'' Michels said.
The Brigham and Women's study found
instead that decaffeinated coffee appeared to decrease the risk of
colorectal cancer, Michels said. Decaf also increases bowel
function, and doesn't contain caffeine, a substance some research
has suggested may cause cancer, Michels said.
The medical community hasn't reached
a consensus on how much coffee, if any, people should drink, and
researchers are examining the beverage's effects on a variety of
ailments, including stomach and esophageal cancers, heart disease
and diabetes, Michels said.