B Vitamins are among the most popular supplements for people looking for an energy boost, but a new study suggests that using too much vitamin B6 and B12 dramatically increases lung cancer in men.  And that higher risk is amplified in men who smoke. 

The study published in a recent edition of the Journal of Clinical Oncology says that taking vitamin B6 and B12 supplements in high doses - like those sold in many stores - appears to triple or almost quadruple some people's risk of lung cancer.  Male smokers taking more than 20 mg of B6 for ten years were were three times more likely to develop lung cancer.  And if those guys with their cigarettes took 55 micrograms of B12 a day for a decade were found to be approximately four times more likely to develop the disease compared to non-users.

"These are doses that can only be obtained from taking high-dose B vitamin supplements, and these supplements are many times the US "Recommended Dietary Allowance'," said Dr. Theodore Brasky of The Ohio State University Comprehensive Cancer Center, co-author of the study.  "This is certainly a concern worthy of further evaluation," he added.

This was the first prospective, observational study to look at the effects of long-term high-dose B6/B12 supplement use and lung cancer risk.  But it's not the first time that research has found links.  In a decade-long study reported in the Journal of the American Medical Association back in 2009, researchers found that taking high doses of vitamin B12 along with B9 (folic acid) was associated with greater risk of cancer and all-cause mortality.