When a woman finds out she is pregnant, she usually tries to eat right, get enough vitamins and minerals, and make sure her baby has all the resources it needs to grow and be healthy. But even if your baby is still just a hope for the future, there’s one nutrient in particular that you should be thinking about: vitamin B9, also known as folic acid or folate.
Folic acid helps the body make new cells. It is essential for building and repairing cells’ genetic material, or DNA, and is key to preventing one of the most common kinds of serious birth defect, called neural tube defects.
One type of neural tube defect is spina bifida, in which the baby’s spinal cord does not close properly, causing problems with the nerves that control the legs and leading to lifelong disability. Another is anencephaly, a fatal defect in which part or all of the brain does not form. About 3,000 pregnancies affected by neural tube defects occur in the United States every year.
“We know that the risk of having a neural tube defect is reduced when women get enough folate, or folic acid,” says Carol Haggans, MS, RD, of the National Institutes of Health Office of Dietary Supplements.
Women who get at least 400 micrograms (mcg) of folic acid daily for at least one month before getting pregnant and through the first trimester reduce their baby’s risk of having a neural tube defect by 50 to 70 percent.
Folic acid is the name for the synthetic form of vitamin B9. The naturally occurring form, called folate, is found in foods such as leafy dark-green vegetables, citrus, beef liver, and lentils. Since January 1998, certain grain products sold in the United States such as bread, wheat flour, and some pastas have been fortified with folic acid. One serving of these fortified foods provides 20 percent of the recommended daily allowance of folic acid.
The U.S. Institute of Medicine recommends that women of childbearing age get at least 400 mcg of folic acid daily, from a vitamin supplement and/or fortified food. If you’re capable of getting pregnant, that means you - even if you’re not planning a pregnancy anytime soon. That’s because a baby’s brain and spine form very early—about 17 to 30 days after conception. At that stage, a woman may not even realize she is pregnant, especially since about half of all pregnancies in the United States are unplanned.
Since fortification began, the number of pregnancies affected by neural tube defects in the United States has fallen by about 25 percent. However, many women still aren’t getting enough folate. A 2010 study by scientists from the U.S. Centers for Disease Control and Prevention found that only 24 percent of women between the ages of 15 and 44 consume the recommended amount of folic acid daily.
A vitamin supplement can be a convenient way of making up the gap. Most multivitamins contain at least 400 mcg of folic acid - check the label to make sure. Chances are if you’re taking one of these pills daily, there’s no need for a separate folic acid supplement. In addition, says Haggans, a multivitamin provides other nutrients such as calcium and iron that many women have trouble getting enough of in their diet.
Once you become pregnant, your recommended daily intake of folic acid increases to 600 mcg. (Nursing mothers should get at least 500 mcg.) It’s important to continue to make sure you get enough folic acid throughout pregnancy, since there’s some evidence that folic acid helps reduce the risk of some heart defects, cleft lip or palate, and premature birth. Plus, your own need for folate increases during pregnancy because you are growing new tissues, including making a lot of red blood cells as your blood volume increases.
For most pregnant women, a prenatal vitamin will provide the right amount of folic acid through pregnancy and breastfeeding - but check with your doctor to be sure.
Some women, such as those who have sickle cell disease, celiac disease, or who have already had a pregnancy affected by neural tube defects, may need higher doses of folic acid. Additionally, certain medications, including methotrexate, metformin, and some antiseizure drugs, interfere with the way the body uses folic acid.
Is too much a concern?
Although mandatory fortification has helped reduce the rate of neural tube defects, the policy has been controversial. In part that’s because some studies have suggested that high blood levels of folate may increase the risk of breast and colon cancer in people over age 50. It’s also well established that high blood folate levels can mask vitamin B12 deficiency, which is a concern in the over-50 population.
Because of the risk associated with folic acid and B12 deficiency, it’s recommended that people consume no more than 1,000 mcg (1 milligram, mg) of synthetic folic acid daily. However, there’s little risk of direct toxicity from excess folic acid - it’s a water-soluble vitamin, so any extra that the body can’t use is simply excreted in the urine. And there’s absolutely no need to worry about getting too much naturally occurring folate in your diet.
Between vitamins and fortified foods, some women occasionally may get more than 1,000 mcg of folic acid in a day - for example, if you take a prenatal vitamin with 800 mcg and eat a bowl of breakfast cereal with another 400 mcg. But don’t sweat it if that happens once in a while, Haggans says.
“Women of reproductive age in particular are probably not getting too much," she said. “It’s probably a little bit safer to err on the side of making sure they’re getting enough.”
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