Neural tube defects (NTDs), which include anencephaly and spina bifida, account for a almost 2,500 birth defects each year in the U.S. Infants born with anencephaly are missing most or all of their brain and die shortly after birth. Most babies born with spina bifida, in which the spinal cord is exposed, grow to adulthood but suffer severe paralysis or other disabilities.
According to the Center for Disease Control and Prevention, the incidence of these defects could be significantly reduced if all women of childbearing age consumed adequate amounts of folate, a B vitamin. Most women don’t know exactly when they get pregnant- and the neural tube of a fetus starts forming immediately. Recommendations for folate advise that any woman capable of becoming pregnant (14-50 years) should get 400 micrograms of folic acid daily from foods fortified with folic acid, from vitamin supplements, or a combination of the two. This is in addition to the folate found naturally in certain foods. Folic acid is the man-made form of folate found in fortified foods and dietary supplements.
The exact role of folic acid in preventing neural tube defects in the fetus is not completely understood yet. Since it is so important to get enough folate even before you know you are pregnant, it may pay to take a multivitamin and mineral supplement, especially if you are planning to become pregnant and you suspect that you are not getting enough from foods fortified with folic acid.
Consumption of folic acid has several other advantages as well, including helping metabolize hormones in the liver, it supports cardiovascular health by lowering homocysteine (an amino acid) levels (an independent risk factor for heart disease). Folic acid is also needed to make genetic material (DNA, RNA), and to manufacture red blood cells. It can also prevent cleft lip. Furthermore, low folate levels are associated with recurrent spontaneous pregnancy loss. High dietary intake of vegetables during pregnancy improves plasma and red blood cell folate concentrations and reduces the risk of folate deficiency. Taking multivitamins prior to conception also significantly reduced the risk of prematurity, and enhances fertility.
Folate in food is about 40%-50% less bioavailable than synthetic folic acid, which is almost 100% bioavailable. However, make sure to keep in mind that eating natural and wholefoods will give a wide range of other vitamins, minerals and fibers that you and your baby need as well.
Signs of deficiency include: anemia; gastrointestinal upsets, diarrhea, weight loss; bleeding gums; irritability. Signs of overdose are: convulsions in epileptics; megadoses can interfere with zinc absorption.
Good food sources are: poultry liver; dark-green, leafy vegetables; legumes; fortified whole-gran breads, cerelas; oranges, grapefruit.
For folate deficiency, the typical dose is 250-1000 mcg per day. For preventing neural tube defects, at least 400 mcg folic acid per day from supplements or fortified food should be taken. Women with a history of previous pregnancy complicated by such neural tube defects usually take 4 mg per day beginning one month before and continuing for three months after conception. The adequate intakes (AI) for pregnant women is 600 mcg; for lactating women, 500 mcg. The tolerable upper intake level (UL) is 1000 mcg for everyone over 18 years of age.