Contrary to other studies, a new study shows that daily supplements of folic acid, vitamin B6, and vitamin B12, do not appear to protect against cancer. But they won’t do you any harm either. Some previous studies have suggested that a daily multi-vitamin with folic acid, B6 and B12 might protect us against cancer.

To find if the treatment really works, researchers analysed data on 5,442 women who participated in the Women’s Antioxidant and Folic Acid Cardiovascular Study. The study’s participants – all women, aged 42 or older (the average age was 63), with either a pre-existing heart disease or three or more risk factors for heart disease, were randomly assigned to receive either a supplement containing 2.5 milligrams (mg) of folic acid, 50 mg of vitamin B6 and 1 mg of vitamin B12, or a placebo. The researchers followed the participants for a period of 7.3 years, from April 1998 through July 2005.

Women who took the supplements were no more or less likely to develop or die from cancer that those who took a placebo, the study found. 187 women in the vitamin supplement group and 192 women in the placebo group developed cancer.

The researchers noted there was a more significant difference among women 65 and older: those who took the daily supplements were 25 percent less likely to develop any kind of cancer and 38 less likely to develop breast cancer.

The study, led by Dr. Shumin Zhang of the Brigham and Women’s Hospital and Harvard Medical school, was published in the Journal of the American Medical Association.

Another study found no difference in the cognitive decline of Alzheimer’s patients with mild to moderate forms of the condition who took high-dose vitamin B supplements, compared to those taking a placebo.