Vitamin B6 cuts lung cancer risk in half

Patients with elevated levels of vitamin B6 and the amino acid methionine in their blood serum had half the risk of developing lung cancer, according to results from a prospective cohort study.

“We were not surprised that vitamin B6 was associated with a reduction in risk,” said lead researcher Dr. Paul Brennan, of the International Agency for Research on Cancer in Lyon, France. “The results for methionine were more surprising as this has not been looked at before.”

B vitamins are necessary for DNA synthesis and methylation. Without them, mutations and abnormal methylation patterns may change gene expression and alter a person’s cancer risk.

The researchers gathered data on serum B vitamins and methionine from 385,747 participants who gave blood in the European Prospective Investigation into Cancer and Nutrition study, carried out in 10 countries between 1992 and 2000.

By 2006, 899 cases of lung cancer had occurred in the cohort and the researchers compared their serum levels of B2, B6, folate (B9), B12, methionine and homocysteine to 1,770 matched controls.

After controlling for smoking and other risk factors, compared to those with the lowest serum B6, patients with the highest serum B6 had a 56 percent reduced risk of lung cancer (P<0.000001).

Higher serum methionine was associated with a 48 percent reduced relative risk of lung cancer (P<0.000001). [JAMA 2010;303 (23):2377-2385]

While there were no similar trends for serum vitamin B2, B12 or homocysteine, high levels of folate were also associated with lower risk of lung cancer, reducing it to two-thirds, when combined with high serum B6 and methionine.

The results were not confounded by smoking, the researchers pointed out, because they were consistent among never, former and current smokers.

However, Brennan said smoking, as a risk factor for lung cancer, is “far and away more important than other factors.”

The researchers said the findings may hint that diet may have an effect on cancer risk, but the full implications are uncertain.

While Brennan said it would not be harmful to maintain high serum levels of these compounds, he would not specifically advise patients to attempt it.

“It is unclear to what extent serum levels are driven by diet and to what extent other factors may intervene,” he said. “Beyond normal recommendations for a healthy balanced diet, it is not possible to give direct recommendations based on these results.”

Source: mims.com