A scientist shown for the first time that folic acid supplements in doses 2.5 to five times the daily requirement "significantly promotes" the growth of existing pre-cancerous or cancerous cells in the mammary glands of rats.
Dr. Young-In Kim said that 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.
The amount of folic acid consumed in North America has increased dramatically in the past 15 years. 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.
His research was published in the online journal PLOS ONE.