Vitamin B supplements are not chemopreventive for lung cancer and may be harmful, according to a study in the Journal of Clinical Oncology.

Theodore M. Brasky, PhD, from the Ohio State University – Comprehensive Cancer Center in Columbus, Ohio, and colleagues conducted a cohort analysis to determine the association between long-term use of supplemental B vitamins on the 1-carbon metabolism pathway and lung cancer risk in the Vitamins and Lifestyle (VITAL) cohort. The researchers included 77,118 participants from 50 to 76 years of age, recruited between October 2000 and December 2002. Participants were followed on average for 6 years. New lung cancer cases were identified from the Surveillance, Epidemiology, and End Results population-based cancer registry. At the beginning of the study, participants completed an extensive questionnaire that included detailed information about dietary supplements, including vitamins B6, folic acid (B9), and B12. The investigators estimated 10-year average daily doses of B vitamins from individual and multivitamin sources.

Use of supplemental vitamins B6, folic acid (B9), and B12 was not associated with lung cancer risk among women. In contrast, however, use of vitamin B6 and B12 from individual supplement sources, but not from multivitamins, was associated with a 30% to 40% increase in lung cancer risk among men. Men who consumed the highest 10-year average daily amounts of B6 (>20 mg/d; hazard ratio, 1.82) and B12 (>55 µg/d; hazard ratio, 1.98) had approximately double the risk relative to men who did not take supplemental B vitamins. The increased risk appeared restricted to men who were current smokers at the beginning of the study. Among these men, lung cancer risks associated with the highest doses of B6 and B12 supplement use were between threefold and fourfold. In addition, the B6 and B12 associations were apparent in all histologic types except adenocarcinoma, which is the type less related to smoking.

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“This sex- and source-specific association provides further evidence that vitamin B supplements are not chemopreventive for lung cancer and may be harmful,” concluded the authors.

Editor’s Note: This article was edited and updated on August 29, 2017.


  1. Brasky TM, White E, Chen CL. Long-term, supplemental, one-carbon metabolism-related vitamin B use in relation to lung cancer risk in the Vitamins and Lifestyle (VITAL) Cohort. J Clin Oncol. 2017 Aug 22. doi: 10.1200/JCO.2017.72.7735