Vitamins and calcium may stop polyp return

USA Today (Society for the Advancement of Education), Oct, 1998

Use of multivitamins and calcium supplements may prevent recurrences of colorectal polyps, which can become cancerous, according to Richard L. Whelan, assistant professor of surgery, director of Colon and Rectal Surgery, and director of the Anorectal Physiology Laboratory, College of Physicians and Surgeons, Columbia University, New York. A four-year study examining factors influencing recurrences of adenomatous, or precancerous, colorectal polyps in 1,162 patients found that multivitamin and calcium intake was associated with a lower recurrence of polyps when compared to patients who did not take the supplements. Polyps are abnormal growths on the bowel wall that may increase in size and become cancerous. Nearly all colon and rectal cancer begins in benign polyps.

The patients completed a questionnaire on personal and family history of colonic disease, cigarette smoking, medication, and vitamin/mineral supplement intake. They were tested for polyps by colonoscopy--a procedure for visually examining the full lining of the colon and rectum using a long, flexible, tubular instrument called a colonoscope.

The study investigated a group of patients who had undergone a previous colonoscopy and had been found to have polyps. These patients were divided into those who took calcium and those who did not. "The patients who had a previous history of polyps and who took calcium developed significantly fewer recurrent polyps on follow-up colonoscopy. In the same group, multivitamins also were associated with a lower recurrence rate of polyps. In addition, vitamins A, C, E, and carotene seemed beneficial, but to a lesser degree than multivitamins and calcium," Whelan notes.

Once a polyp is removed completely, its recurrence is very unusual, though the same factors that caused the polyp to form remain present. New polyps will develop in at least 30% of people who previously had polyps. "Although the results of this study are encouraging, they did not prove that calcium and multivitamin usage actually caused the lower rate of polyp recurrence observed. A larger, randomized trial would be needed to study this further," Whelan cautions.