Norwegians researchers report, heart patients in their country who take folic acid and vitamin B12 supplements are more likely to die from cancer, as compared to those who do not, since foods in Norway unlike in many countries are not enriched with folic acid.

Their findings reveal, lung cancer rates were 25% higher amongst those taking supplements in comparison with the general population. Overall, deaths due to cancer, including from other causes were also higher in the supplement group.

As well, they said folic acid taken over a period of more e. g. 3-years fuelled the growth of cancers too small to be detected, raising fresh doubts about the benefits of fortifying foods with folic acid.

Folic acid, a B vitamin, is necessary for the body to make healthy new cells, and is essential for women to take it before pregnancy for preventing serious birth defects like spina bifida in their babies.

It is for this reason, USA, including many other countries fortify flour and grains with folic acid. But, the findings of recent studies have raised concerns it may increase the risk of cancer.

The three year Norwegian studies involved people with heart disease, and who were given folic acid and vitamin B12 supplements to help lower the levels of the amino acid homocysteine, linked with heart attacks and strokes. However, the studies failed to show any heart benefits derived from the supplements, despite following the patients for over 3-years to find out if they had any effect on the risk of cancer.

On combining the findings of the two clinical trials involving over 6,800-patients, researchers found folic acid and vitamin B12 supplements meant a higher risk of cancer diagnosis, dying from cancer, including dying from any other cause.

Not the first study to suggest folic acid increases a person’s risk of developing cancer, a study in March and another in April also indicate folic acid supplements and fortifying foods with folic acid, raise the risk of prostate and colon cancer, respectively. Researchers note that the most common cancers associated with folic acid are colorectal, lung, prostate and blood cancer.

The report’s findings have been published in the 18th November issue of the Journal of the American Medical Association.