Folic acid linked to cancer and all-cause mortality

26 Nov 09

Their analysis of data from two randomised controlled trials, involving 6,837 patients with ischaemic heart disease treated with B vitamins or placebo, found that 10% of those taking folic acid developed cancer versus 8.4% of those on placebo. Median follow-up was 39 months.

Overall mortality from cancer in the folic acid group was 4% compared with 2.9% for placebo. The researchers said the cancer deaths observed were mainly driven by increased incidence of lung cancer.

The intervention dose of 0.8mg of folic acid a day was four to six times higher than the average dose delivered by mandatory dietary fortification in the US and twice the recommended daily allowance.

Folate is recommended in UK clinical guidance to prevent foetal neural tube defects, treat macrocytic anaemia and protect against toxicity associated with anticonvulsant drugs and methotrexate.

Study leader Dr Marta Ebbing, consultant physician at the department of heart disease, Haukeland University Hospital, said further research must consider the implications of long-term supplementation.

JAMA 2009;302:2119-26