Heart disease patients in Norway, a country where folic acid is not fortified into food, noticed higher cancer and death risks after receiving vitamin B12 and folic acid treatments. Research was published in the Journal of the American Medical Association.
Many studies have found relationships between folate and colorectal cancer risk, but the association is non-existent in other cancers. Researchers explain a deficiency in folate may promote cancer initially, but high folic acid dosage may promote cancer cell growth.
Folic acid fortification has been mandatory in many countries since 1998, including the United States. This helps reduce neural-tube birth defect risks.
This study, among others, has recently raised questions about cancer risk in relation to folic acid.
For the study, researchers performed placebo trials on 6,837 patients having ischemic heart disease. Patients were either treated with B vitamins or a placebo, and the study took place from 1998 to 2005. Follow ups were performed through 2007.
Randomly selected, patients received one of four supplements: (1) folic acid, vitamin B12, and vitamin B6; (2) folic acid and vitamin B12; (3) vitamin B6; (4) placebo.
Researchers discovered 288 individuals who did not receive vitamin B12 and folic acid supplementation were diagnosed with cancer, when compared to 341 individuals who did not receive either. This denotes a 21 percent increased risk.
Also, an increased death risk of 38 percent was noticed when comparing those who did not receive either folic acid or vitamin B12 to those who received neither.
The largest cancer increase in patients receiving both folic acid and vitamin B12 was lung cancer. No significant changes were noticed in patients who took the vitamin B6 supplement.
Researchers explain additional research is required and this may cause new safety regulations on food fortification and supplementation.