Excessive Vitamin B Supplements Can Cause Lung Cancer In Men: Study

Men who consumed high doses of vitamin B supplements have a significantly higher risk of getting lung cancer, a study published Tuesday said.

Researchers from Ohio State University and the National Taiwan University studied more than 77,000 people aged between 50 and 76 in the U.S. and found that men who took high dosages of vitamins B6 and B12 faced 30 percent to 40 percent increased risk of lung cancer.

For men who were smokers, the risk was even higher, quadrupling over next in case of excessive intake of vitamin B12 and increasing three times when excessive doses of B6 was consumed.

However, similar increased cancer risk was not seen in women or with the vitamin B9 said the study.

The participants were recruited from the state of Washington between 2000 and 2002 and were made to answer questions about their vitamin use over the previous 10 years. Researchers used statistical techniques to adjust for many factors including personal smoking history, alcohol consumption, and personal history of cancer or chronic lung disease. Results revealed that just over 800 of the study volunteers developed lung cancer over an average follow-up of six years.

According to the National Institutes of Health (NIH), people in the age group of the participants required 1.7 mg of vitamin B6 and 2.4 mcg of vitamin B12. These levels in were 11 times more than the recommended daily amount of B6 and 23 times that of B12 among those who were studied and were consumed individually and not from multivitamins or a part of their diet.

“What we found was that men who had used dietary supplements, in particular, B6 and vitamin B12, at high doses for 10 years, were at significant increased risk of developing lung cancer,” Theodore Brasky, Ph.D, the lead author of the study at the Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute said, according to CNN.

He added that there was no clear idea on how the risk of cancer might be influenced by the vitamin intake and that the study does not link higher doses of the vitamins to higher rates of lung cancer conclusively.

"When we're talking about what to be concerned about most: If you're a male smoker and you want to take B vitamins, you can stop smoking," Brasky said, adding that those who took high doses of vitamin B should quit the habit.

While the supplements might help those with anemia or celiac disease and prevent them from feeling tired, large doses may prove to be very useful for an average healthy person.

According to the NIH, high intakes of vitamin B6 can cause severe and progressive sensory neuropathy characterized by loss of control of bodily movements. Other symptoms of too much vitamin B6 include extreme sensitivity to sunlight, nausea, painful, unsightly skin patches and heartburn. Vitamin B12, on the other hand, has a low potential for toxicity.

B12 is found in animal products like meat, eggs, and milk and is usually present as cyanocobalamin in dietary supplements. On the other hand, B6 is available in dietary supplements in the form of pyridoxine and multivitamin-mineral supplements also contain the vitamin. Americans get most of their B6 from fortified fruits and starchy vegetables, cereals, chicken, and beef according to the NIH.