Increased intakes of vitamin B6 may reduce lung cancer risk

Higher blood levels of vitamin B6 may reduce the risk of lung cancer by about 50 per cent, says a new French study.

Out of 385,747 participants in the European Prospective Investigation into Cancer and Nutrition (EPIC), the researchers identified 899 people with lung cancer and matched them with 1,770 cancer-free people (1). Based on blood analysis the results showed that increasing blood levels of vitamin B6 were associated with lower risks of lung cancer. A similar risk reduction was observed for the amino acid methionine, which extended to never, former, and current smokers – indicating that smoking habits were not confounding the results. Above-median serum measures of both vitamin B6 and methionine, assessed on average 5 years prior to disease onset, were associated with a reduction of at least 50 percent on the risk of developing lung cancer. In addition, increased serum levels of vitamin B9 (folate) were, when combined with B6 and methionine, associated with a 66 percent lower risk of lung cancer.

As this correlation does not prove causation, more research is needed to clarify the role of B vitamins and methionine in lung cancer, the researchers commented. However, given their involvement in maintaining DNA integrity and gene expression, these nutrients have a potentially important role in inhibiting cancer development, and offer the possibility of modifying cancer risk through dietary changes, they concluded.

One in three Europeans is a smoker, while it is one in five in the US. Tobacco smoke contains 60 compounds which are known carcinogens. The oxidative stress levels of smokers are significantly greater than non-smokers, and as such there is a bigger drain on the levels of antioxidants in the body. A large proportion of lung cancer cases occur among former smokers and a non-trivial number of lung cancer cases occur also among never smokers, particularly among women in parts of Asia.

1. Johansson M. et al. Serum B Vitamin Levels and Risk of Lung Cancer. JAMA. 2010; 303(23):2377–2385.