Study Finds That Taking Heavy Doses Of Vitamin B Supplements May Increase Lung Cancer Risk
A new study has found a link between heavy vitamin B6 and B12 supplementation and lung cancer in men, especially men who smoke.
The researchers report that the risk is two to four times greater for long-term users of the supplements compared to non-users.
The study analyzed data for just over 77,000 participants, age 56-70, in the VITamins And Lifestyle (VITAL) cohort study, a long-term observational study that examined the association between vitamin and mineral supplementation and cancer risk.
Participants reported their vitamin B usage, including dosage information, for the 10-year period prior to the study.
The research team found the highest risk for male smokers taking more than 20 mg of B6 or 55 micrograms of B12 a day for 10 years.
Male smokers taking B6 were at three times greater lung cancer risk; those taking B12 were at four times greater risk. Non-smoking men were at twice the risk as those not taking the supplements. Women were not found to be at greater risk.
The study accounted for a range of factors that could influence the outcome, including age, race, education, alcohol consumption, body mass, and family history of lung cancer.
With these and additional factors weighed in, the risk remained high for men taking high doses of the supplements, particularly smokers.
“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,” said lead study author Theodore Brasky, PhD in a press statement.
The recommended daily intake of vitamin B6 is 1.3 milligrams in men and women ages 19-50; 1.7 milligrams in men aged 51 and older; and 1.3 milligrams in women aged 51 and older, according to the National Institutes of Health.
For B12 the recommended daily amount is 2.4 micrograms for ages 14 and older. The amounts of both vitamins associated with cancer risk in this study were significantly higher than the government’s recommendations.
These findings contradict a long-held belief that vitamin B supplementation may reduce cancer risk.
Previous research found a link between high levels of B6 and a reduction in lung cancer risk for smokers and nonsmokers, but the participant sample size was considerably smaller than in the latest study.
This was an observational study, and it’s important to note (as with all studies of this type) that the findings are a correlation, not proof of causation.
A second study is underway to replicate these results in another large participant group.
The study was published in the Journal of Clinical Oncology.
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