Role of Folic Acid, Vitamin B12, and Vitamin B6 in cancer prevention?

 Folic acid, Vitamin B12, and Vitamin B6 in cancer prevention?

One common topic or area of concern for my blog readers is regarding cancer prevention. For some, vitamins including folic acid, B12, and B6 are thought to have a possible role in preventing certain types of cancers in women. A recent trial published in the Journal of American Medicine Association (JAMA), explored the potential cancer preventing benefits of these vitamins in (5442) female health professionals over the age of 42 (Zhang et al, 2008).

INTERVENTION: Daily supplementation of a combination of 2.5 mg of folic acid, 50 mg of vitamin B(6), and 1 mg of vitamin B(12) (n = 2721) or placebo (n = 2721).

MAIN OUTCOME MEASURES: Confirmed newly diagnosed total invasive cancer or breast cancer.

RESULTS: A total of 379 women developed invasive cancer (187 in the active treatment group and 192 in the placebo group). Compared with placebo, women receiving the active treatment had similar risk of developing total invasive cancer.

Conclusion: Unfortunately, despite the large number of participants in this trial as well as the relatively long duration of the trial (7.3 years), this study failed to find any benefit of folic acid, Vitamin B12, or Vitamin B6 in the prevention of breast or total invasive cancer in women.

The results of this particular study contradict the results of a previous study that suggested that Vitamins B6 and B12 may reduce the risk of breast cancer, particularly in postmenopausal women:

Vitamin intake and breast cancer risk

Reference:

Zhang SM, Cook NR, Albert CM, Gaziano JM, Buring JE, Manson JE. Effect of combined folic acid, vitamin B6, and vitamin B12 on cancer risk in women: a randomized trial. JAMA. 2008 Nov 5;300(17):2012-21.