Wednesday, June 23, 2010

Do B vitamins reduce lung cancer risk?

Smoking is the major risk factor for lung cancer, according to a new study published in JAMA, higher levels of vitamin B6 and methionine in the blood was associated with lower risk of lung cancer.

This was a large scale IARC study with 520,000 volunteers across Europe, part of the EPIC cohort. Blood samples were taken from both the case group and the control group and the amount of B6 and methionine measured.

The researchers found that there was a lower risk of lung cancer with a higher level of B6 and methionine whether they were smokers or non-smokers. Overall, people with above average levels of B6 and methionine had 50% reduction in the risk of developing lung cancer than those with below average levels.

Critics say that the blood samples were taken on only one occasion and a cohort study cannot prove a cause and effect for a reduced risk of lung cancer for B6. Furthermore, B6 and methionine are found in meat and potatoes, but it was unknown whether eating more of this food would make a difference to the risk of developing lung cancer because a lower level of these substances in the blood may be due to poor absorption.

Source: Johansson M, Relton C, Magne Ueland P, et al. "Serum B Vitamin Levels and Risk of Lung Cancer". JAMA 2010; 303: 2377-2385

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