How Folic Acid Can Help Prevent Birth Defects

If you plan to have children some day, here's important information for the future mother to be think folic acid now.

Folate is a B vitamin found in a variety of foods and added to many vitamin and mineral supplements as folic acid, a synthetic form of folate. Folate is needed both before and in the first weeks of pregnancy and can help reduce the risk of certain serious and common birth defects called neural tube defects, which affect the brain and spinal cord.

The tricky part is that neural tube defects can occur in an embryo before a woman realizes she's pregnant. That's why it's important for all women of childbearing age (15 to 45) to include folate in their diets: If they get pregnant, it reduces the chance of the baby having a birth defect of the brain or spinal cord.

"Adequate folate should be eaten daily and throughout the childbearing years," said Elizabeth Yetley, Ph.D., a registered dietitian and director of FDA's Office of Special Nutritionals.

Folate's potential to reduce the risk of neural tube defects is so important that the Food and Drug Administration requires food manufacturers to fortify enriched grain products with folic acid. This will give women one way to get sufficient folate: by eating fortified breads and other grain products, such as enriched pasta, rice, waffles and cereal bars.

Other ways to do this are:

• Eat fruits, dark-green leafy vegetables, dried beans and peas, and other foods that are natural sources of folate.
• Eat folic acid-fortified enriched cereal grain products and breakfast cereals.
• Take a vitamin supplement containing folic acid.

Nutrition information on food and dietary supplement labels can help women determine whether they are getting enough folate, which is 400 micrograms (0.4 milligrams) a day before pregnancy and 800 micrograms a day during pregnancy.

Neural Tube Birth Defects

The technical names of the two major neural tube birth defects reduced by adequate folate intake are anencephaly and spina bifida. Babies with anencephaly do not develop a brain and are stillborn or die shortly after birth. Those with spina bifida have a defect of the spinal column that can result in varying degrees of handicap, from mild and hardly noticeable cases of scoliosis (a sideways bending of the spine) to paralysis and bladder or bowel incontinence. With proper medical treatment, most babies born with spina bifida can survive to adulthood. But they may require leg braces, crutches, and other devices to help them walk, and they may have learning disabilities. About 30 percent have slight to severe mental retardation.

The national Centers for Disease Control and Prevention estimate that about 2,500 infants with spina bifida and anencephaly are born each year in the United States.

Other maternal factors also may contribute to the development of neural tube defects. These include:

• family history of neural tube defects
• prior neural tube defect-affected pregnancy
• use of certain antiseizure medications
• severe overweight
• hot tub use in early pregnancy
• fever during early pregnancy
• diabetes.

Folate Link

Scientists first suggested a link between neural tube birth defects and diet in the 1950s. The incidence of these conditions has always been higher in low socioeconomic groups in which women may have poorer diets. Also, babies conceived in the winter and early spring are more likely to be born with spina bifida, perhaps because the mother's diet lacks fresh fruits and vegetables--which are good sources of folate--during the early weeks of pregnancy.

In 1991, British researchers found that 72 percent of women who had one pregnancy with a neural tube birth defect had a lower risk of having another child with this birth defect when they took prescription doses of folic acid before and during early pregnancy.

Another study looked at folic acid intake in Hungarian women. The evidence indicated that mothers who had never given birth to babies with neural tube defects and who took a multivitamin and mineral supplement with folic acid had less risk in subsequent pregnancies for having babies with neural tube defects than women given a placebo.

These studies led the U.S. Public Health Service in September 1992 to recommend that all women of childbearing age capable of becoming pregnant consume 0.4 mg of folate daily to reduce their risk of having a pregnancy affected with spina bifida or other neural tube defects.

That corresponds to FDA's Daily Value for folic acid, which is 400 micrograms for nonpregnant women, as well as children 4 and older and adult men. For pregnant women, the Daily Value jumps to 800 micrograms. Daily Values are dietary reference numbers used on the Nutrition Facts panel on food labels to show the amounts of various nutrients in a serving of food.

Many women between 19 and 50 consume much less than 400 micrograms of folate a day, according to the U.S. Department of Agriculture.

Folate Sources

Folate occurs naturally in a variety of foods, including liver; dark-green leafy vegetables such as collards, turnip greens, and Romaine lettuce; broccoli and asparagus; citrus fruits and juices; whole-grain products; wheat germ; and dried beans and peas, such as pinto, navy and lima beans, and chickpeas and black-eyed peas.

Under FDA's folic acid fortification program, which became effective January 1998, the agency requires manufacturers to add from 0.43 mg to 1.4 mg of folic acid per pound of product to enriched flour, bread, rolls and buns, farina, corn grits, cornmeal, rice, and noodle products. A serving of each product will provide about 10 percent of the Daily Value for folic acid. Whole-grain products do not have to be enriched because they contain natural folate. Some of the natural folate in non-whole-grain products is lost in the process of refining whole grains.

Folate also can be obtained from dietary supplements, such as folic acid tablets and multivitamins with folic acid, and from fortified breakfast cereals.

A report recently released by the Institute of Medicine indicates that the evidence suggests that folic acid, the synthetic form of folate, may be better absorbed than folate found naturally in foods. The report also points out that, if taken in adequate amounts, food folate may eventually be demonstrated to be as effective as folic acid.