May 21, 2008 -- The number of women of childbearing age with low blood folate levels has dramatically declined since the U.S. government mandated the addition of folic acid to cereals, breads, pasta, and other foods a decade ago.
The FDA's folic acid fortification program, launched in 1998, increased the folic acid content of the most commonly eaten bread and grain products.
Folate is a water-soluble B vitamin (B9) that occurs naturally in leafy green vegetables, citrus fruits, dried beans, and peas. Folic acid is a synthetic form of the vitamin that is essential to good health, particularly during pregnancy. Inadequate amounts of folic acid during pregnancy can lead to serious birth defects of the brain, spinal cord, or their protective coverings called neural tube defects. One of the most common neural tube defects is spina bifida.
Margaret A. McDowell, MPH, of the CDC, and colleagues evaluated data from the National Health and Nutrition Examination Survey (NHANES) to determine how folate levels in people aged 4 and older have changed over time. NHANES is an annual survey designed to monitor the health and nutritional status of U.S. infants, children, and adults.
The researchers looked at information regarding red blood cell (RBC) folate levels and serum folate status. RBC folate levels give doctors information about a person's long-term folate intake.
In addition to an increased risk of neural tube defects, low RBC folate levels have been linked to many other health problems, including slow growth rates in babies and young children, anemia, digestive disorders, and heart palpitations in adults. Serum folate is a measure of recent folate consumption. Low levels are an early warning that a person may not be getting enough of the vitamin.
Earlier surveys have shown that most individuals, including women of childbearing years, did not consume enough folate. But that trend appears to have dramatically changed. The most recent analysis shows that America's short- and long-term folate levels increased significantly from 1988 to 2006.
The researchers noted "very large increases" in blood folate levels of those aged 4 and older when comparing data from 1988 to 1994 to measurements taken the year following the launch of the folic acid fortification program (1999-2000). Small improvements continued from 1999 to 2006.
The survey findings revealed a "significant reduction" in the occurrence of long-term folate deficiency in all women of childbearing age, regardless of race or ethnicity.
Improved folate status of pregnant women theoretically should mean fewer neural tube defects. According to the CDC, folic acid fortification resulted in a third fewer such defects between 1995 and 2002.
Neural tube defects develop early in pregnancy. In addition to eating foods fortified with folic acid, doctors encourage all women of childbearing age to take a daily multivitamin containing 400 micrograms of folic acid and to eat a healthy diet.