A new study published in The Journal of the American Medical Association takes a closer look at how folic acid and vitamin B12 affect cancer risks.
Researchers in Norway studied more than 6,800 people with ischemic heart disease who were treated with folic acid plus vitamins B12 and B6, folic acid plus vitamin B12, vitamin B6 alone, or a placebo.
The researchers determined that treatment with folic acid plus vitamin B12 led to higher cancer rates, in addition to deaths from cancer and other causes.
Unlike many countries, including the United States, Norway does not enrich its food supplies with folic acid.
According to the Los Angeles Times, the Norwegian researchers also pointed out: "Although the folic acid doses in the study were higher than what the typical American would consume through fortification alone, they were below the limits set by our Institute of Medicine."
The researchers say the study's results need confirmation in other populations.