Vitamin D and calcium supplements do not reduce the risk for the development of colorectal adenomas in patients who have had a precancerous colorectal adenoma removed, according to a study published October 15 online ahead of print in the New England Journal of Medicine. 


Lead author John A. Baron, MD, and fellow investigators studied 2,259 patients aged 45 years to 75 years and who had had polyps removed from their colon. The patients, who had no remaining polyps at enrollment, were randomly assigned to receive 1,000 IU of vitamin D3 daily, 1,200 mg of calcium daily, both of these, or none of these. Almost half of the patients (43%) had one or more adenomas at follow-up screening colonoscopy in the 3 to 5 years following the initial screening. There was no significant difference in the frequency of new polyps in patients who took vitamin D supplements, calcium supplements, or both, when compared with those who took neither. 


Previous research has suggested that vitamin D and calcium supplementation have beneficial effects against colorectal cancer, according to one of the study’s authors Dennis J. Ahnen, MD. “It could be that vitamin D and/or calcium work later in the process of carcinogenesis to prevent dangerous cancers, but not their precancerous predecessors,” he said.