Folic acid (vitamin B9), vitamin B6, and vitamin B12 are thought to play a role in preventing cancer and heart disease.

However, researchers at Harvard Medical School recently showed women who have a high risk of heart disease did not improve their risk of developing cancers, such as multiple myeloma, after taking the vitamins.

The study participants received a daily combination of folic acid, vitamin B6, and vitamin B12 or placebo for more than 7 years between April 1998 and July 2005. During that time, the researchers recorded any …