A new study, published Tuesday in the Journal of Clinical Oncology, has found a link between high doses of vitamin B6 and B12 supplements and increased lung cancer risk, especially among men who smoke.
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Researchers recruited more than 77,000 adults ages 50-76 in Washington and collected data on the participants’ vitamin use over the past 10 years, including dosage information.
They found that the risk nearly doubled for non-smoking men taking the vitamin supplements, tripled for male smokers taking high doses of B6 and quadrupled for male smokers consuming high doses of B12.
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“Our data shows that taking high doses of B6 and B12 over a very long period of time could contribute to lung cancer incidence rates in male smokers. This is certainly a concern worthy of further evaluation,” lead study author and Ohio State University professor Theodore Brasky said in a statement.
Male smokers taking more than 20 milligrams of B6 or 55 micrograms of B12 daily for 10 years had the highest lung cancer risk.
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These doses were more than 11 times the recommended daily amount of B6 — and 23 times that of B12.
Women were not at greater risk, according to the study.
Previous studies on the subject vary in their findings. Some have linked B6 with a lower risk of lung cancer, and another found B12 had no impact on lung cancer risk whatsoever, CNN reported.
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But the observational study does not prove cause-and-effect — only an association between the vitamin supplements and lung cancer.
The Council for Responsible Nutrition, an industry trade group, urged readers not to make a causal connection and instead take away the fact that cigarette smoking is still the most important factor in lung cancer risk.
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Researchers are currently working to study the relationship between the vitamin supplements and lung cancer risk with a larger participant group.
Read the full study.