High Doses of B Vitamins Linked to INCREASED Lung Cancer in Male Smokers

MedicalResearch.com Interview with:

Theodore M. Brasky, PhD Research Assistant Professor The Ohio State University – James Comprehensive Cancer Center Columbus, OH 43201

Dr. Brasky

Theodore M. Brasky, PhD
Research Assistant Professor
The Ohio State University – James Comprehensive Cancer Center
Columbus, OH 43201

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Prior literature has been suggestive of both a protective and harmful effect of certain B vitamins on lung cancer risk. We wanted to examine the association of intakes of vitamins B6, folic acid (B9), and B12 from supplements –which are typically taken at very high doses– and lung cancer risk in a large, prospective study of 77,000 men and women living in Washington State. The study is unique as it was designed specifically to examine associations of dietary supplements with cancer occurrence. We found that men who took high doses of vitamin B6 and B12 from individual supplements over a long period of time (meaning, doses much higher than the US RDA and much greater than what one would receive from taking a multivitamin over the long term) were at nearly 2-fold increased risk of lung cancer compared to men who did not have B6 or B12 intake from any supplemental source. This finding of increased risk appeared to be specific to men who were current smokers. Among them, long term high-dose supplementation was associated with 3-4 fold increases in lung cancer risk. We observed no increased risk for any of the supplements – B6, B12, or folic acid – with lung cancer risk in women or women who smoked.

MedicalResearch.com: What should readers take away from your report?

Response: Our findings indicate a potential synergism or magnification of the effect of smoking on lung cancer risk among men due to high dose B6 or B12 supplementation. Combustible tobacco smoke is the main cause of lung cancer and indeed many cancers and chronic diseases. Cigarette smoking accounts for 1 in 5 deaths in the US. Male smokers concerned about their lung cancer risk need to strongly consider quitting. Those who smoke and take high-dose B vitamins should consider cutting back to doses closer to the US RDA (i.e., from a multivitamin) or getting their nutrients from diet. However, some people are at risk of B vitamin deficiency – such as those with Crohn’s disease. Those individuals should discuss their options with their physician.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: We are planning several replicative analyses in additional prospective epidemiologic studies to further corroborate our findings in men and women. 

MedicalResearch.com: Is there anything else you would like to add?

Response:. Readers need to understand that this research examines the possible relation between B6 and B12 supplements and cancer occurrence in participants who did not have lung cancer at the beginning of the study. We were unable to address whether lung cancer patients had improved or worsened prognosis if they took these supplements. Our findings replicate prior results for B12 in particular. However, no standalone study can prove a causal link and further replication (as is the scientific process) is really needed.

I have no financial or other conflict of interest

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Theodore M. Brasky, Emily White, Chi-Ling Chen. Long-Term, Supplemental, One-Carbon Metabolism–Related Vitamin B Use in Relation to Lung Cancer Risk in the Vitamins and Lifestyle (VITAL) Cohort. Journal of Clinical Oncology, 2017; JCO.2017.72.773 DOI: 10.1200/JCO.2017.72.7735

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