Vitamins are commonly associated with health benefits, but research continues to suggest that men who take vitamin B6 and B12 in high doses are at higher risk of developing lung cancer.
What the research says
A study published in 2017 found that using vitamin B6 and B12 individual supplements was associated with a 30 percent to 40 percent increase in lung cancer risk among men. There was no notable risk for multivitamin usage. Men who take the vitamins and smoke showed an even higher risk of lung cancer. There was no increased risk for women, the study noted.
A study published in 2021 backed up the findings, although it solely looked at dietary vitamin B12 levels.
Marshfield Clinic Health System oncologist/hematologist Dr. Dean Delmastro says the issue is with men taking very high doses of these particular B vitamins. Levels are much higher than you would find in an average multivitamin.
How are they linked?
Why this link between B vitamins and lung cancer exists remains an open question. If they are responsible for the increase in lung cancer, Dr. Delmastro suggested a reason why.
“Probably it modifies, at least in smokers, some of the pathways in which carcinogens are metabolized,” Dr. Delmastro said. “In my view, however, smokers should not be taking anything other than, at most, a standard, one-a-day multivitamin.”
Dr. Delmastro said unless there is a specific medical reason you need to take high doses of specific B vitamins, you should avoid doing so. He added that not smoking or quitting smoking is the most important thing you can do to avoid lung cancer.
“I think anyone concerned about this issue should talk to their primary care provider, especially if they’re a smoker,” Delmastro said.
He added that the more information you can give your medical provider, the better that provider will be able to advise you on living a healthy lifestyle.
For questions about cancer risk, talk to a Marshfield Clinic Health System provider.
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Does this also apply to former smokers who started taking B vitamins after they stopped smoking?
Hi Amanda, The risk is for men who take B6 or B12 vitamins. Individuals should talk to their doctor for their personal health recommendations. As stated in the research, "Use of supplemental vitamins B6, folate, and B12 was not associated with lung cancer risk among women. In contrast, 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. When the 10-year average supplement dose was evaluated, there was an almost two-fold increase in lung cancer risk among men in the highest categories of vitamin B6 (> 20 mg/d; hazard ratio, 1.82; 95% CI, 1.25 to 2.65) and B12 (> 55µg/d; hazard ratio, 1.98; 95% CI, 1.32 to 2.97) compared with nonusers. For vitamin B6 and B12, the risk was even higher among men who were smoking at baseline." -Thanks, Jordan
So what is the incidence of lung cancer if I do not supplement B vitamins, don't smoke and am between 50 and 90.
Hi, Michael. Here is a statistic from the American Cancer Society: "Overall, the chance that a man will develop lung cancer in his lifetime is about 1 in 15; for a woman, the risk is about 1 in 17. These numbers include both smokers and non-smokers. For smokers the risk is much higher, while for non-smokers the risk is lower."
You can read more about that here: https://www.cancer.org/cancer/non-small-cell-lung-cancer/about/key-statistics.html
For an individualized assessment of your risk, it's important to share your family history with your doctor. He/she can give you a response more accurate to you.
-Kirstie
Thanks. Exactly what I was looking for. Now, how much of what types of "B" give you that 30-40% increased risk?
Michael – Dr. Delmastro gave this in response to your question: "The main point is that anything above the normal amount of Vitamin B6 or B12 that is found in multivitamins would be considered high and should not be taken unless there is a medical reason such as Vitamin B12 deficiency. The blood level of Vitamin B12 and others do NOT correlate to lung cancer risk. It is only how much supplemental Vitamin B12 is ingested above and beyond what is in a regular multivitamin."
He also added, "I think people may be confusing the blood level of B12 with taking extra in a supplement. The blood level is not the problem; it's taking the supplement. Naturally occurring B12 in food and in a regular multivitamin are not the problem."
I hope that helps provide clarification, and thank you for reading Shine365. -Kirstie
What levels of B12 are considered to be a high level.
Hi, Dona. Thank you for your patience. Dr. Delmastro said, "The main point is that anything above the normal amount of Vitamin B6 or B12 that is found in multivitamins would be considered high and should not be taken unless there is a medical reason such as Vitamin B12 deficiency. The blood level of Vitamin B12 and others do NOT correlate to lung cancer risk. It is only how much supplemental Vitamin B12 is ingested above and beyond what is in a regular multivitamin."
Thank you for reading Shine365. -Kirstie
Does having too much of the B vitamins naturally (not pills) still lead to a high risk of lung cancer?
The article says, "Use of vitamin B6 and B12 from individual supplement sources." It makes no mention of dietary consumption of foods naturally high in B vitamins.