A recent study shows that men who took high doses of Vitamin B6 and B12 had a higher risk of lung cancer; association was highest among smokers
The study discovered a 30% to 40% increased risk of lung cancer among men who take vitamin B from individual supplements, and not from multivitamins or diet alone. However, the effect seemed to come from current smokers who exceed the recommended daily amounts of vitamins by a lot.
“I think these results point to a synergism between high-dose B vitamins, smoking and lung cancer risk among men.” said Theodore Brasky, epidemiologist at the Ohio State University College of Medicine
The study specifically shows that men who smoke and take high levels of vitamin B6 had triple the risk of developing lung cancer over six years, in comparison with those who do not take supplements. For vitamin B12, the risk nearly quadrupled. These levels are more than 11 times the recommended daily amount of B6, and 23 times that of B12.
“If you look at B-vitamin supplement bottles … they are anywhere between 50-fold the US recommended dietary allowance (to) upward of 2,100-fold,” Brasky said. B12 injections have also become “in vogue” in recent years, he said.
Of course, if taken in smaller quantities, these vitamins are involved in several vital processes in the body, including DNA replication. However, many high-dose supplements claim to boost enervy and provide unproven benefits.
“That’s marketing. That’s not science,” he said.
At the same time, other researchers have found different results. A few studies linked vitamin B6 with lower lung cancer risk, while another discovered that B13 had no impact on risk at all.