We all know the importance of eating a balanced diet, but recent research has shown that folic acid is especially important for every woman of childbearing age.
In fact, it is so important that the Food and Drug Administration has issued a new regulation that will require the food industry to enrich bread and cereals with folic acid to help women consume enough folic acid each day.
I talked with Lisa Summers, coordinator of nurse midwifery research at the Johns Hopkins Hospital, and to Dr. Ben Caballero, director of the division of human nutrition at the Johns Hopkins School of Hygiene and Public Health, to find out more.
Q: Why is folic acid so important?
A: Folic acid is essential to the development of a healthy fetus. Without it, there is the risk of having a baby with neural tube defects (NTDs). Neural tube defects occur when the bony casing around the baby's spinal cord fails to close properly.
The most common form of NTD is spina bifida, which can result in partial paralysis for the child. In its most severe form NTDs can result in an encephaly, a condition in which major parts of the skull and brain are missing.
Nearly 2,500 babies born each year in the United States are affected by NTDs.
Q: How much folic acid should a woman consume?
A: The Centers for Disease Control and Prevention recommends that all women of childbearing age consume 400 micrograms of folic acid a day -- more than twice the Recommended Dietary Allowance for other women.
Q: I'm not pregnant, but I may decide to have children in the near future. Should I be worried about how much folic acid I'm getting?
A: Yes. The problem is that the neural tube develops very quickly after conception. In fact it should be completely developed by the 28th day after conception. Many women don't know at this stage that they are pregnant. For this reason the CDC recommends that all women of childbearing age consume 400 micrograms of folic acid each day.
Q: What kinds of foods contain folic acid?
A: Folic acid, one of the B vitamins, is present in green vegetables, especially asparagus and broccoli, legumes like kidney beans and navy beans, and in fruit and fruit juices.
In addition, starting in December all cereals will be fortified with 100 micrograms of folic acid per serving and bread will be fortified with 70 micrograms of folic acid per slice.
Q: Should I take a folic acid supplement?
A: Currently, most American women get only half the recommended daily allowance of folic acid. The aim is to try to increase vitamins in the diet so that women won't need to take supplements. However, if you are not sure you're getting enough, you can choose to take a supplement.
An over-the-counter prenatal vitamin will give you 400 micrograms of folic acid a day. Alternatively, you can take a pill containing only folic acid.
Don't rely on multivitamins, since these do not contain the recommended amount of folic acid. Taking multiple doses of multivitamins to achieve the right dose of folic acid is not a good idea, since it could lead to ingestion of harmfully high levels of vitamin A and D.
Q: Is there any risk from consuming more than 400 micrograms of folic acid each day?
A: Folic acid is a water-soluble vitamin, so any excess consumed will be eliminated in your urine. However, high doses of folic acid can mask a vitamin B12 deficiency. This deficiency will cause irreversible neurological damage if it is not diagnosed and treated. In view of this possibility, the CDC recommends that women should not consume more than 1,000 micrograms of folic acid daily.
Women who have had an NTD-affected pregnancy may wish to discuss the use of a higher dose of folic acid with their health-care provider.
Q: I'm already pregnant and I haven't been taking a folic acid supplement. Should I be worried about NTDs?
A: The chances are that as long as you are eating a balanced diet, you're probably getting enough folic acid. But you should talk to your physician or nurse-midwife about vitamin supplementation when you are planning a pregnancy.
Dr. Genevieve Matanoski is a physician and epidemiologist at the Johns Hopkins School of Hygiene and Public Health. She is a founding director of the school's Institute for Women's Health Research and Policy.