30 Mar 2015 Blackmores Institute Metformin and vitamin d3 combo promising in preventing colorectal cancer 30 Mar 2015 Share Share on LinkedIn Share on Facebook Share on Twitter Share on Google+ Share on Pinterest News A combination of the oral diabetes drug metformin and vitamin D3 shows great promise as a preventative for colon cancer, new research reveals. Cancer researcher Li Li, MD, PhD, from Case Western Reserve University in Cleveland, Ohio, US, wondered if the two compounds each individually show promise in preventing colon cancer, surely it's worth trying the two together to see if even greater impact is possible. × To continue reading this article, please Log In or Sign Up for access.