WEDNESDAY, July 20, 2005 (HealthDayNews) -- Calcium supplements may help prevent the development of polyps that can lead to colorectal cancer, but there's no evidence calcium actually prevents the malignancy itself, researchers say.
In a review of two earlier studies involving more than 1,300 individuals, Israeli researchers concluded that calcium supplements provide a moderate protective effect against development of colorectal adenomatous polyps -- small, usually benign polyps found in about 30 percent of middle-aged and older Americans.
However, "this does not constitute sufficient evidence to recommend the general use of calcium supplements to prevent colorectal cancer," the investigators concluded. Their findings appear in the current issue of the journal The Cochrane Library.
Previous research in animals and surveys of people with high-calcium diets suggested that the mineral may offer some protection against colorectal cancer, one of the leading cancers in both men and women.
"Calcium supplementation is relatively cheap, likely to be safe, readily available and has other positive metabolic effects on conditions that occur with aging," such as osteoporosis, high blood pressure, kidney stones and weight gain, Dr. Anca Zalmanovici, one of the review authors, said in a prepared statement.
If further studies do confirm that calcium is effective, it could be given to people who've previously had polyps and are therefore at increased risk for colorectal cancer, the review authors said.
The U.S. National Cancer Institute has more about colorectal cancer prevention.