In a recent study published in the Journal of the National Cancer Institute, 930 patients diagnosed with recent colorectal adenomas (average age at baseline: 61 years; history of at least one such lesion excised within three months before study entry; no known polyps remaining) were assigned randomly to receive 1,200 mg/day of calcium carbonate or a placebo.Follow-up colonoscopies administered to each patient approximately one and four years after original group assignment assessed the presence of colorectal polyps - hyperplastic polyps, tubular adenomas, and more advanced lesions affecting the large bowel.
Nine hundred thirteen subjects completed at least one follow-up examination following randomization. Calcium supplementation at 1,200 mg daily appeared to reduce the risk of developing all three types of adenomas - hyperplastic polyps (risk ratio: 0.82 compared to placebo); tubular adenomas (0.89 compared to placebo); and histologically advanced neoplasms (0.65 compared to placebo).
The authors suggest that calcium supplementation may protect against the development of advanced colorectal lesions to a greater degree than other types of polyps considered as a single group. They also note that total calcium intake over 1,200 mg a day may be necessary, and that dietary fiber and dietary fat may also play a role.
Source
- Wallace K, Baron JA, Cole BF, et al. Effect of calcium supplementation on the risk of large bowel polyps. Journal of the National Cancer Institute, June 16, 2004;96(12):921-5.
