A daily calcium supplement protects against colon polyps, particularly the advanced type that go on to become cancer, new research suggests.
"These new data makes it increasingly likely that calcium will have a protective effect on cancer itself, not just on polyps," stated Dr. John A. Baron, from the Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire.
Calcium supplementation has been tied to a modest reduction in the overall risk of pre-cancerous polyps. "However, few studies have examined the effect of calcium on the risk of different types of (colon) lesions," the investigators note in the Journal of the National Cancer Institute.
In the Calcium Polyp Prevention Study, 913 participants took either a calcium supplement or an inactive "placebo" each day. The subjects were followed for four years to compare the occurrence of colon polyps.
"All types of polyps occurred less frequently in the calcium treatment group than in the placebo group," the investigators report. Calcium use reduced the risk of all polyps by 14 percent and the risk of advanced polyps by 35 percent.
The findings also suggest that a total daily calcium intake greater than 1200 mg as well as a high intake of dietary fiber and a low intake of fat is needed to "optimize" the preventive effects of calcium.
Commenting on the findings, Baron said: "Calcium is not a sexy drug, and to some people it might seem implausible that something as simple and familiar as calcium might lower the risk of a major cancer. This new research shows that the calcium effect is particularly pronounced for advanced (polyps), those with the closest connections to cancer."
Journal of the National Cancer Institute, June 16, 2004.