Individuals with high blood levels of vitamin B6 may be less likely to develop lung cancer compared with their counterparts with lower vitamin B6 levels, according to the results of a study published in the Journal of the American Medical Association.
Lung cancer remains the leading cause of cancer death in the United States. Avoiding tobacco is one of the best ways to prevent development of the disease, but researchers continue to investigate other ways to prevent lung cancer, including dietary factors.
Between 1992 and 2000, the European Prospective Investigation into Cancer and Nutrition (EPIC) obtained blood samples from 380,000 subjects from 10 countries; 899 of these subjects developed lung cancer during a 12-year follow-up period. These subjects were matched to a control group of 1,770 by age, gender, country, and date of blood collection.
The researchers measured blood levels of four B vitamins (B2, B6, folate, and B12) and two amino acids (methionine and homocysteine). They found that individuals whose B6 levels ranked in the top 25% of all subjects had less than half the risk of lung cancer compared with those with the lowest B6 levels. Similarly, those with high levels of methionine appeared to have about half the risk of lung cancer compared with those with low levels of the amino acid. Although high folate (B9) offered less protection, high levels of the combination of B6, folate, and methionine appeared to decrease the risk of lung cancer by two-thirds, regardless of smoking status.
The researchers concluded that high blood levels of B6 and methionine were both inversely associated with risk of lung cancer. While it may be too soon to reach the conclusion that supplementing with these nutrients is a viable method of preventing lung cancer, the preventive effects of these nutrients warrant further investigation.
 Johansson M, Relton C, Ueland PM, et al. Serum B vitamin levels and risk of lung cancer. JAMA. 2010; 303: 2377-2385.
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