Toronto, Jan 22 (IANS): Folic acid supplements, if taken in high amounts, may increase the risk of developing breast cancer.

“The experiment in my lab has shown for the first time that folic acid supplements in doses 2.5-5 times the daily requirement 'significantly promotes' the growth of existing pre-cancerous or cancerous cells in the mammary glands of rats,” said Young-In Kim, a physician and researcher at St Michael's Hospital here.

Although some studies have found it may offer protection against breast cancer, recent studies have suggested that taking high amounts of folic acid may increase the risk.

“This is a critically important issue because breast cancer patients and survivors in North America are exposed to high levels of folic acid through folic acid fortification in food and widespread use of vitamin supplements after a cancer diagnosis,” Kim added.

Cancer patients and survivors in North America have a high prevalence of multivitamin and supplement use, with breast cancer patients and survivors having the highest prevalence, said the study published in the journal PLOS ONE.

Women are routinely advised to take folic acid supplements before becoming pregnant and while pregnant to prevent neural tube birth defects such as spina bifida.