Long term use of metformin, the commonly prescribed “cornerstone” type 2 diabetes drug, increases the risk of vitamin B12 deficiency.
A deficiency of this vitamin raises levels of the amino acid homocysteine in the blood; higher levels are considered a risk factor for heart disease.
Metformin causes malabsorption of vitamin B12 and this negative effect increases over time. The study establishing this link was posted online at the site of the British Medical Journal on May 20, 2010 and the full-text version is now available at: http://bit.ly/aml8wr.