Folic acid (also known as vitamin B9 or folate) is one of the few nutrients known to prevent neural tube birth defects such as spina bifida, which affects about one in 1,000 pregnancies each year in the United States. The Centers for Disease Control report that women who take the recommended daily dose of folic acid starting one month before they conceive and throughout the first trimester reduce their baby's risk of birth defects such as spina bifida by up to 70 percent.
This alone is reason enough to make sure you take folic acid before you get pregnant and during pregnancy, but there may even be other benefits as well. Some studies have shown that women who don't get enough folic acid may increase their risk of miscarriage, as well as cleft lip and palate, limb defects, and certain types of heart defects in their babies.
Your body needs this nutrient for the production, repair, and functioning of DNA, our genetic map and a basic building block of cells, so getting enough is particularly important for the rapid cell growth that occurs during pregnancy. Folate is also required for a complex metabolic process that involves the conversion of one amino acid in your blood (homocysteine) into another amino acid (methionine). If you don't get enough folate, you can end up with too much homocysteine in your blood, which is thought to contribute to some birth defects. Elevated levels of homocysteine in pregnancy also have been linked to blood clots, placental abruption, recurrent miscarriages, and stillbirth. Researchers are trying to find out whether taking folic acid throughout pregnancy decreases your risk for these problems. Finally, folate helps make normal red blood cells, prevent anemia, and produce the nervous system chemicals norepinephrine and serotonin.
How much do I need?
A month before you start trying to get pregnant, you should be taking 400 micrograms (mcg) of folic acid a day to reduce your baby's risk of neural tube defects. (Your baby's neural tube starts to develop about three weeks after conception, which is about as soon as you're likely to find out you're pregnant.) In fact, since half of pregnancies are unplanned, the U.S. Public Health Service recommends that all women of childbearing age get 400 mcg of folic acid each day.
Once you're pregnant, you'll need at least 600 mcg daily, although many practitioners suggest 800 mcg and some prenatal vitamins contain 1,000 mcg. Folic acid is a water-soluble vitamin, so your body will flush out the excess if you take too much. For some women, there's an exception to this rule; getting too much folate may hide a B12 deficiency. It's uncommon to be low in B12 if you're a healthy young woman with a varied diet, but it can be a problem for you if you're a vegetarian, particularly if you don't consume dairy products. Ask your healthcare provider if you think you may be at risk.
Women who've had a child with a neural tube defect have a significantly higher risk of having a second with the same defect. Healthcare providers now advise these women to take ten times as much folic acid — 4,000 mcg or 4 milligrams (mg) — starting one month before conception and continuing through the first three months of pregnancy. See your practitioner for a prescription for the supplement if you fall into this category.
Should I take a supplement?
Definitely. If you're like most people, you don't get the amount of folate you need from your diet, and research shows that the body actually absorbs the synthetic version of this vitamin (found in supplements and enriched foods) much better than the version that occurs naturally in certain foods. On the days you can't stomach your prenatal vitamin in early pregnancy, at least take a separate folic acid supplement. (These pills are small and easy to get down.) But eating plenty of folate-rich foods won't hurt either, since the recommended daily amount you're supposed to get from your supplement is designed to complement the amount you're likely to get from food sources.
What are the best food sources?
Food manufacturers are required by the Food and Drug Administration to add folic acid to enriched grain products such as breakfast cereals, bread, pasta, and rice so that each serving contains at least 20 percent of the daily requirement, and some breakfast cereals contain 100 percent (400 mcg) or more. Dark leafy greens are also a good source of folate, as are legumes such as lentils and chickpeas. Other sources include the following:
- 1/2 cup cooked lentils: 179 mcg
- 1 cup boiled collard greens: 177 mcg
- 1/2 cup canned chickpeas: 141 mcg
- 1 medium papaya: 115 mcg
- 1 cup cooked frozen peas: 94 mcg
- 4 spears steamed or boiled asparagus: 88 mcg
- 1/2 cup steamed broccoli: 52 mcg
- 1 cup strawberries: 40 mcg
- 1 medium orange: 39 mcg
The signs of folic acid deficiency can be subtle. You may have diarrhea, loss of appetite, and weight loss, as well as weakness, a sore tongue, headaches, heart palpitations, and irritability. If you're only mildly deficient, you may not notice any symptoms at all, but you won't be getting the optimal amount you need for your baby's early embryonic development. That's why all women of childbearing age need to take folic acid, even if they feel perfectly well.