ORAL CALCIUM INHIBITS RECTAL EPITHELIAL PROLIFERATION IN FAMILIAL ADENOMATOUS POLYPOSIS

Calcium reduces colorectal cell turnover and might therefore protect a gainst neoplasia. The inhibitory effects of dietary calcium were teste d in a double-blind controlled trial in patients with familial adenoma tous polyposis who had undergone previous abdominal colectomy and ileo rectal anastomosis. Patients received supplemental calcium carbonate ( 1500 mg/day) or placebo tablets for 6 months; sigmoid-oscopy oscopy wa s performed before and after treatment. Rectal biopsies were maintaine d in short-term organ culture, and crypt cell production rate (CCPR) w as measured stathmokinetically. A total of 25 patients completed the t rial; polyp counts were obtained before and after treatment in all and CCPR values in 16. Calcium treatment reduced the mean(s.e.m.) CCPR fr om 4.72(0.48) to 2.42(0.48) cells per crypt per h (P < 0.05), while va lues for placebo were unchanged (5.46(1.21) versus 5.08(1.17) cells pe r crypt per h). Calcium had no demonstrable effect on the number, size or distribution of rectal polyps. The ability of oral calcium supplem entation to suppress rectal epithelial proliferation supports its pote ntial to prevent development of colorectal carcinoma in high-risk indi viduals.