Study: Calcium May Cut Cancer Risk
Tue Mar 19, 2002

By PAUL RECER, AP Science Writer

WASHINGTON - Among people with low-calcium diets, even a modest increase in the nutrient appears to lower the risk of some types of colon cancer by about half, researchers report.

In a study appearing Wednesday in the Journal of the National Cancer Institute (news - web sites ), researchers at Harvard evaluated the diet and colon cancer history of 135,000 men and women in two large health surveys. They found that those who consumed 700 to 800 milligrams of calcium daily significantly reduced their risk of left-side colon cancer by 40 to 50 percent.

"We did not study high levels of calcium so we do not know what to recommend for higher doses," said Dr. Kana Wu, a researcher at the Harvard School of Public Health and the first author of the study.

She said the results of the study need to be confirmed by other research before a recommendation can be made regarding dietary calcium and colon cancer, but it is clear that "it is good to avoid very low calcium intake."

Monika Kraus, an oncology dietitian at the Washington Cancer Institute of the Washington Hospital Center, said the study is important because it suggests that adequate calcium in the diet has a benefit beyond building strong bones.

"This is important because a lot of people don't get it and there needs to be more emphasis on calcium," said Kraus.

She cautioned, however, that the Harvard study needs to be confirmed by other researchers and that people should not go overboard on taking calcium pills.

"I wouldn't recommend overdosing on calcium," said Kraus. "The study showed that more than 700 mg a day did not improve the effect."

Kraus said getting calcium from food, such as lowfat milk or dairy products, should be the first choice, but "if one can't get it from food, then a supplement (pill) might be beneficial."

In the Harvard study, the authors identified 626 colon cancer cases among the 88,000 women enrolled in the Nurses Health Study, and 399 men with colon cancer among the 47,000 in the Health Professionals Follow-up Study. Both of the large studies monitored the health habits and diet of the men and women over many years starting in the 1980s.

By evaluating diets of those who developed colon cancer and those who did not, the researchers found that adequate levels of calcium in the diet significantly reduced the risk of cancer on the left side of the colon, but had no statistically significant protection for other types of colon cancer.

The left side of the colon includes the last segment of the large intestine. The right side is higher up the gut and attached to the small intestine. Wu said the incidence of cancer in the different parts of the colon is about equal.

Wu said it is unknown why the cancer-calcium data was different for the sections of the colon, but said "there is some evidence that there are two different tumor types" in the colon.

According to the American Cancer Society (news - web sites), colon cancer is diagnosed in more than 90,000 Americans annually and causes about 47,000 deaths.

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On the Net:

Journal of the National Cancer Institute: http://jncicancerspectrum.oupjournals.org/

http://story.news.yahoo.com/news?tm..._colon_cancer_3