Increased folic acid from supplements, fortified foods not likely to affect B12 deficiency
Taking folic acid supplements or eating fortified grain products is unlikely to worsen problems related to low levels of vitamin B12, according to researchers at the National Institutes of Health and five other institutions in the United States, Ireland and Norway.
In the United States, bread, cereal and other enriched flour products have been fortified with folic acid (the synthetic form of the vitamin folate) since 1998. Women with low levels of folate are at increased risk for conceiving a child with birth defects of the brain and spinal cord known as neural tube defects. The number of infants born with these birth defects has fallen since fortified foods were introduced.
Researchers have been concerned that the level of folic acid in fortified grains — needed to reduce women’s risk for conceiving a child with a neural tube defect — might be too high for other people. These concerns stem from earlier studies that found higher rates of anemia and other blood abnormalities in people with low B12 levels who also had high folate levels. The people with low B12 and high folate levels were more likely to have anemia than did people with low B12 levels and normal folate levels.