High B vitamins cut cancer risk by two thirds

A study of almost 400,000 participants finds that those with higher blood levels of vitamin B6, folic acid and the essential amino acid methionine cut their risk of lung cancer by two thirds.

This study, published today in the Journal of the American medical Association (JAMA. 2010;303[23]:2377-2385) by Dr Paul brennan and colleagues from the International Agency for Re¬search on Cancer finds that having a high blood level of vitamin B6 and methionine alone cut risk by a half, in both smokers and non-smokers. Methionine is a sulphur-containing amino acid, found in protein, which also helps, along with vitamin B6 and folic acid, the body to protect and repair DNA. Many critical DNA processes require methylation.

Faulty methylation is indicated by raised homocysteine levels and these nutrients help to improve methylation and reduce homocysteine levels. Raised homocysteine is also a risk factor for several types of cancer. “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,” the authors write. They add that deficiencies in nutrient levels of B vitamins have been shown to be high in many western populations. “Our results suggest that above-median se¬rum measures of both B6 and methionine, assessed on average 5 years prior to disease onset, are associated with a reduction of at least 50 percent on the risk of developing lung cancer.

An additional association for serum levels of folate was present, that when combined with B6 and methionine, was associated with a two-thirds lower risk of lung cancer,” the authors write. Lung cancer continues to be the most common cause of cancer death in the world and, unknown to many, is not only associated with smoking but also chronic exposure to exhaust fumes. The incidence is much higher in urban environments, especially where diesel pollution is high, than rural environments. If this link between high levels of methylating nutrients – B6, folic acid and methionine – proves to be causal, the researchers say that identifying optimum levels for reducing future cancer risk would appear to be appropriate.

I recommend that everyone, at least, takes a daily multivitamin providing 20mg of vitamin B6 and 200mcg of folic acid. While methionine can be supplemented, it is rich in seeds, nuts, beans, fish and meat. Achieving a sufficient intake in these by eating a protein serving with each meal, should suffice. I also recommend testing your homocysteine level with a home-test kit. If your level is high you’ll be advised to take specific high dose B vitamins. Specific homocysteine-modulating nutrient formulas exist for this purpose. Having a low homocysteine is consistent with having a long and healthy lifespan.