Energy-boost vitamin B pills linked to lung cancer
Men who take energy-boosting vitamin B supplements could be at double the risk of lung cancer. A study found men who take high doses of vitamins B6 or B12 over a long period were much more likely to develop the disease. If they also smoked, their risk of cancer was up to four times higher if they took the supplements.
The body needs vitamins B6 and B12 to help ensure red blood cells are healthy and to process proteins, fat and carbohydrate. They are naturally found in meat, fish, cheese, eggs and milk, as well as fortified breakfast cereals, but millions of people take supplements as well.
Vitamin B6 and B12 pills are often marketed as energy or metabolism-boosting products. The research, published in the Journal of Clinical Oncology, is the latest to challenge the alleged health benefits of vitamin supplements.
Excessive doses of vitamin E, beta-carotene and folic acid (vitamin B9) have all previously been linked to increased cancer risk. For the new study, researchers in the United States (U.S.) followed 77,000 people aged between 50 and 76 as part of the Vital (Vitamins and Lifestyle) study – a major US investigation into the impact of vitamins and minerals on cancer risk.
Participants provided detailed information about their B-vitamin use over the past 10 years, including what dose they took. Previously, doctors had thought supplements could help reduce cancer risk.
But they found men who took high doses of vitamin B6 and B12 for ten years were at a higher risk of cancer – even when factors like age, smoking history, family history of cancer and alcohol consumption were taken into account.
Male smokers who took more than 20mg of B6 a day for 10 years were three times more likely to develop lung cancer than people who did not take supplements.
The risk was four times greater for male smokers taking at least 55 micrograms of B12 a day for 10 years. But there was no similar risk in women who took the supplements.
Study lead Dr. Theodore Brasky, of The Ohio State University Comprehensive Cancer Centre, said: “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.
“In fact, all men who used these supplements in high doses for a decade had approximately double the risk developing lung cancer, and in men who smoked, the risk was three to four times as great.”
He warned many vitamin B supplements contained doses which were “much, much higher than the daily recommended amount”.
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