Can dietary supplements influence recurrence of colorectal polyps?

This study examined whether dietary supplements, such as a multivitamins, are associated with the recurrence (return) of colorectal adenomas (polyps).  

Colorectal adenomas or polyps are non-cancerous growths on the lining of the large intestine. After being removed, colorectal adenomas can reoccur. Although adenomas are benign (not cancerous), they can develop into colorectal cancer over time. Patients with recurring adenomas are more likely to develop colorectal cancer. Dietary supplements (such as multivitamins, minerals, herbs) are frequently used by many people in the hope that they will be healthier and more able to fight off disease. While it is known that diet and lifestyle can influence colorectal adenoma recurrence, it is not clear whether dietary supplement use is associated with recurrence of colorectal adenomas. 

This study followed 565 patients with colorectal adenomas treated with surgery to remove the polyps. Patients were questioned on their dietary supplements use 1 year before their diagnosis and for up to 5 years afterwards. Out of the 203 patients who used dietary supplements, 32.5% experienced a recurrence of the adenomas. Of the 362 patients who did not use dietary supplements, 26.5% experienced a recurrence. Patients who experienced a recurrence of the adenomas were more often men, slightly older and had more often previous adenomas. On the other hand, patients who used dietary supplements were more often women, more physically active, had more history of colorectal cancer and consumed more vegetables and fruits.

In summary, the authors of this study did not find a significant association between using dietary supplements and developing a recurrence of colorectal adenomas.

This study was based on a questionnaire, which sometimes may include subjective data.