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General Information About NTDs, Folic Acid, and Folate
What are neural tube defects? collapsed
- Neural tube defects are serious birth defects of the brain and spinal cord. The two most common neural tube defects are spina bifida (a spinal cord defect) and anencephaly (a brain defect). Neural tube defects develop very early during pregnancy when the neural tube—which forms the early brain and the spinal cord—does not close properly.
- The baby’s neural tube closes during the first weeks of pregnancy, often before a woman knows that she is pregnant. If a woman consumes folic acid before and during early pregnancy, it can help increase the chance of her baby’s neural tube closing properly. Waiting until the first prenatal visit (typically, the 6th to 12th week of pregnancy) to start folic acid consumption will not prevent neural tube defects. Therefore, to help prevent neural tube defects, it is important for women to start folic acid consumption before pregnancy begins.
- Occasionally, some women will take the daily recommended amount of folic acid and still have a baby with a neural tube defect. Although the majority of neural tube defects can be prevented by getting 400 micrograms (mcg) of folic acid every day, some neural tube defects have other causes. If you have had a baby affected by a neural tube defect, be sure to discuss with your doctor or a genetic counselor your risk of having another pregnancy affected with a neural tube defect.
What is folic acid? collapsed
- Folic acid is a B vitamin. If a woman consumes enough folic acid (400 micrograms (mcg) daily) before and during early pregnancy, it can help prevent her baby from having a neural tube defect. Women can do this by taking a vitamin supplement containing the recommended amount of folic acid or eating enough food that is fortified with folic acid. Fortified foods include enriched breads, pastas, rice, and some breakfast cereals.
Is folic acid the same as folate? collapsed
- The terms “folic acid ” and “folate” often are used interchangeably. However, folate is a general term used to describe the many different forms of vitamin B9: folic acid, dihydrofolate (DHF), tetrahydrofolate (THF), 5, 10-methylenetetrahydrofolate (5, 10-MTHF), and 5-methyltetrahydrofolate (5-MTHF) 1.
- Folic acid is the synthetic (that is, not generally occurring naturally) form of folate that is used in supplements and in fortified foods, such as rice, pasta, bread, and some breakfast cereals. In many scientific studies done in countries around the world, folic acid has been shown to be effective in preventing neural tube defects 2-6.
- Natural folate can be found in foods such as leafy green vegetables, citrus fruits, and beans. A woman should eat a balanced diet rich in natural folate from food. However, it is very difficult for most women to get the daily recommended amount of folate through food alone 7 (see Table 2: http://ods.od.nih.gov/factsheets/Folate-HealthProfessional/).
- Supplements containing forms of folate other than folic acid (such as 5-MTHF) should not be confused with the natural food folate found in fruits and vegetables. The effectiveness of these supplements in preventing neural tube defects has not been studied.
Why is folic acid used in food fortification instead of other folate forms? collapsed
- Food fortification is the process by which vitamins and minerals are added to foods.
- Folic acid is more heat-stable than natural food folate, which is broken down easily by heat and light; therefore, folic acid is better suited for food fortification because many fortified products, such as bread, are baked 8.
- Folic acid has been shown to be effective in preventing neural tube defects in randomized control trials and food fortification programs 2-6.
- Folic acid is absorbed easily by the body, and studies have shown that it can increase blood folate concentrations (the amount in the blood) across populations (including those with the MTHFR TT genetic variant) 9, 10.
- No scientific studies exist that show that supplements containing other forms of folate [such as 5-methyltetrahydrofolate (5-MTHF)] can prevent neural tube defects.
What is blood folate concentration? collapsed
- Blood folate concentration is the amount of folate that can be measured in the blood (many forms of folate are included in the measure). When a woman gets folic acid through fortified foods or supplements, her blood folate concentration increases. Having enough folate in the blood can reduce her risk of having a baby affected by a neural tube defect 11.
- Once a woman starts consuming 400 micrograms (mcg) of folic acid every day, it can take several months for her to have a blood folate concentration that is high enough to help prevent neural tube defects.
- The two most important factors that determine whether a woman has a blood folate concentration that is high enough to help prevent neural tube defects are the amount of folic acid consumed each day and 11 the length of time it is consumed before pregnancy. When taking supplements, more is not necessarily better. The Centers for Disease Control and Prevention recommends women to take 400 mcg of folic acid every day, starting at least one month before getting pregnant.
Where can I find folic acid in the United States and in what amounts? collapsed
- In the United States, folic acid can be found in foods with mandatory or voluntary fortification, or in supplements. All products labeled as “enriched” are required by the U.S. Food and Drug Administration to be fortified (mandatory fortification) with folic acid, in addition to other micronutrients. The dietary labels on these products must specify that folic acid is included as an ingredient 12.
- Researchers currently estimate that in the United States, people consume about 140 micrograms (mcg) of folic acid each day from mandatorily fortified foods 13.
- Voluntarily fortified foods, such as some ready-to-eat cereals, can be fortified with up to 400 mcg of folic acid in each serving.
- In the United States, supplements containing folic acid generally have 400 to 800 mcg of folic acid per dose, but doses up to 1,000 mcg are allowed without a prescription 14.
- The amount of folic acid consumed from mandatorily fortified foods alone (about 140 mcg each day, on average) occurs at much lower levels than the amount consumed from supplements containing folic acid (about 400 to 1,000 mcg from each dose) or from voluntary fortification (400 mcg from each serving) 13.
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- Page last reviewed: March 20, 2017
- Page last updated: March 20, 2017
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