Certain birth defects have decreased by almost 20 percent since the government in 1998 required enriched grain foods to be fortified with the nutrient folic acid, a new study says.
But women of childbearing age should still take extra amounts of the vitamin.
Folic acid, also known as folate, is a type of vitamin B found in green leafy vegetables, citrus fruits, dried beans and liver. Folic acid is an essential vitamin the body needs for proper functioning, particularly during the first few weeks of life.
Scientists have known since the 1950s that low levels of folic acid during pregnancy can cause dangerous neural tube defects in newborns, though it is not yet known how the vitamin works.
What Are Neural Tube Defects?
The most common types of neural tube defects are spina bifida and anencephaly, which occur when the spinal column fails to close in the growing fetus. Anencephalic fetuses usually do not develop a functional brain or spinal cord and are often stillborn. Spina bifida infants can live to adulthood, with varying degrees of cognitive and physical disabilities, ranging from mild curvature of the spine to severe paralysis and mental retardation.
Although the fortification has lowered the rates, neural tube defects still occur in approximately 1 in 1000 births, with about 2,500 affected children born in the United States every year.
The new study by the Centers for Disease Control in the latest issue of The Journal of the American Medical Association reveals that while the folic acid fortification program has been successful overall, babies are still being born with defects because pregnant women may still not be getting enough of the vitamin in their diets.
Enriched foods are designed to give an average eater about 100 micrograms of folic acid per day. But experts say women need at least 400 micrograms to protect their babies from neural tube defects.
Prenatal screening may also be playing a role in overestimating the fortification program's success. "Many neural tube defects are screened out early in pregnancy, since once detected, many women choose to terminate their pregnancies," says Dr. Hope Ricciotti, a women's nutrition specialist at Beth Israel Deaconess Medical Center in Boston.
"This means that the study may underestimate the real number of babies conceived with neural tube defects. Nonetheless, this is a major medical victory for preventive health."
Even With Fortification, Women Still Need More Folic Acid
Doctors strongly advise women take a folic acid supplement to achieve the recommended daily 400 micrograms. "We don't want people to become complacent because certain foods are now fortified," says Margaret Honein, a CDC scientist and the study's lead author. "For women it is still important to take supplements."
For most of us, the simplest and safest way to get folic acid is to take a daily multi-vitamin, which has the added bonus of providing other important nutrients like calcium and iron.
Physicians also stress that all women of childbearing age monitor their folic acid intake, and overall health in general, regardless of whether they are trying to become pregnant. The CDC estimates that half of all pregnancies are unplanned, which means that many women may not know they are carrying until their fetus is several weeks old, after much of the brain and spinal cord have already been developed.
"Women need optimal amounts of folic acid during conception and early fetal development to reduce the chances of having a baby with neural tube defects," says Wahida Karmally, director of nutrition at the Irving Center for Clinical Research at Columbia University in New York.
Fad diets and unhealthy weight loss programs may also work against the developing baby. "My concern would be when women follow low-carbohydrate diets for weight reduction or management, their diets will be very deficient in several nutrients including folic acid," Karmally says.
Too Much Folic Acid?
Can you take too much folic acid?
"There doesn't appear to be a risk factor associated with high levels of folic acid intake, but we acknowledge that this is an important area for future research," says Honein.
Folic acid is a water-soluble vitamin that has no known toxicity, so any excess vitamin in your system simply leaves your body when you go to the bathroom.
But people over 50 should be careful about taking in high levels of folic acid. The vitamin can have negative effects on people with "pernicious anemia," a type of anemia that occurs mainly within the elderly.