Doctors have discovered that when a person has high levels of vitamin B6 and the amino acid methionine in their blood, it may lower their risk for lung cancer. The beneficial effect was seen in both smokers and non-smokers, as well as those who used to smoke and have quit.

To arrive at their findings, which were published in the Journal of the American Medical Association (JAMA), researchers studied blood samples from more than 519,000 patients where were part of a larger cancer and nutrition study. The study subjects were drawn from 10 countries over the course of eight years (1991-2000). What the scientists focused on were vitamin B6 and methionine levels in nearly 900 lung cancer cases and compared them to healthy patients. The two groups were matched according to their country of origin, their age and sex, and the time that the blood sample was collected.

The individuals were then placed in groups based on their levels of vitamin B6 in their blood. Vitamin B6 is an important nutrient that helps to maintain the health of our blood while also aiding the body in the break down of proteins. Methionine is involved in the metabolism of B vitamins.

What the scientists observed was that when vitamin B6 and methionine levels were higher, it coincided with a lower risk for lung cancer. In fact, individuals with the highest levels of the vitamin had their risk for lung cancer reduced by as much as 56% when compared to people with low vitamin B6 levels. Additionally, those with the highest methionine levels saw a 48% reduction in lung cancer risk.

Previous studies had investigated the role, if any, of vitamin B6 in reducing the lung cancer risk in smokers, but the current study encompasses a broader range of people by including people who used to smoke but quit, as well as people who never smoked in the first place.

While the exact mechanism is not known, it is has postulated that deficiencies in vitamin B6 might possibly raise the risk mutations that stem from damage to the DNA. These mutations could lead to the development of cancer. The authors of the study caution that people should not interpret the results as a call to begin taking vitamin supplements, or view vitamin B6 as a way to counter the hazardous effects of smoking, which is the primary risk factor for lung cancer. Any sort of dietary supplements should be taken under the guidance of your doctor.

However, the data is another indicator that a proper diet is a key component in maintaining good health, and getting enough vitamins is an important part of that. Good sources of the vitamin B6 include beans, whole grains, meat, poultry, fish and fruits and vegetables.

The findings should not be interpreted as a justification to begin or continue smoking. If you smoke, then it is advisable to quit. If you don't smoke, then never start.