Is the recommended daily dose of folic acid enough for everyone?

by Bria Monaldo

Folic acid and pregnancy

DNA strandIt's well-known that folic acid is part of a healthy regimen for getting pregnant and during pregnancy. What isn't as well-known is that not all women metabolize folic acid in the same way. This could mean that the recommended daily dosage of 400 micrograms may not be enough for everyone. Scientific research is now beginning to reveal that small differences in your DNA, specifically changes in genes in your folate metabolism pathway can affect how your body processes folic acid. Folate and folic acid are forms of a water soluble B-group vitamin that must be replenished each day, even if you metabolize it normally. Folate occurs naturally in food and folic acid is the synthetic form of this vitamin. Folate plays a critical role in the development of the neural tube into a brain and spinal cord during the first few weeks of pregnancy. A deficiency in this important vitamin could result in a pregnancy affected by a neural tube defect, such as spina bifida.

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Understanding the folate pathway

The folate pathway is a series of about 28 genes that regulates how your body metabolizes folic acid and turns it into a resource for critical metabolic activities such as DNA synthesis and repair, red blood cell production and cell division. During pregnancy, it's these genes that are responsible for the development of the brain and spinal cord of the fetus. The folate pathway is a tightly regulated biological process and if not coordinated properly in the early weeks of pregnancy, may result in a possible neural tube defect for the embryo. Studies continue to examine genes in the folate pathway of mothers with a spina bifida affected child. The same genes are also being studied in mothers with an unaffected child and comparisons between these two groups are reviewed by the research team. Scientists are looking for changes or mutations in these genes that might be different between the two groups of women. Preliminary findings show that abnormalities in genes involved with the folate pathway may disrupt a normal biochemical function and negatively impact the development of the neural tube early in pregnancy. Ongoing research is underway to determine if a genetic test could help determine a woman’s risk of having a pregnancy affected by spina bifida even before she conceives.

High dose folic acid for women at risk

The good news is that if a woman is identified to be at high-risk for having a pregnancy affected by spina bifida, a prescription dose level of folic acid, 4 milligrams vs. the recommended 400 micrograms, could help reduce her risk. Today, the only known risk factors for having a spina bifida affected pregnancy are: 1. A previously affected pregnancy 2. Taking anti-epilepsy drugs such as valproate or carbamazepine. For women with these risk factors, a high dose folic acid (ten times the regular recommended dose – 4 milligrams vs. 400 micrograms) is prescribed. Studies have shown this regimen may reduce a woman's risk by up to 70 percent. However, it is estimated that 95 percent of women who give birth to children with neural tube defects have no history of a prior affected pregnancy or anticonvulsant therapy. Spina bifida continues to be the most common permanently disabling birth defect and recent publications suggest spina bifida is estimated to occur in 1 in 2,858 pregnancies each year in the U.S. New methods for assessing a woman’s risk by examining the genetics in her folate pathway may allow doctors to intervene with a prescription regimen early enough to reduce the number of children born with spina bifida. Learn more about the scientific study. Medical references: - American College of Obstetricians and Gynecologists (ACOG). Neural tube defects. Washington (DC): American College of Obstetricians and Gynecologists (ACOG); 2003 Jul. 11 p. (ACOG practice bulletin; no. 44). - De-Regil LM, Fernández-Gaxiola AC, Dowswell T, Peña-Rosas JP. Effects and safety of periconceptional folate supplementation for preventing birth defects. Cochrane Database Syst Rev 2010;CD007950. - Parker SE, Mai, CT, Canfield MA et al. 2010. Updated National Birth Prevalence Estimates for Selected Birth Defects in US 2004-2006. Birth Defects Research (Part A) 88:1008-1016.