General Information About NTDs, Folic Acid, and Folate
- General Information About NTDs, Folic Acid, and Folate
- Folic Acid Safety, Interactions, and Effects on Other Outcomes
- Folic Acid and Its Link to Other Health Outcomes
- Folic Acid Fortification and Supplementation
- Neural Tube Defects Surveillance
- 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.
- 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.
- 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 (see Table 2).
- 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.
- 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.
- 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.
- 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.
- The DVs are the amounts of nutrients people should consume as part of their daily diet. The % DV is how much a certain nutrient in a single serving of food contributes to the daily diet. The recommended amount of folate to consume each day (100% DV) is actually based on the amount needed to prevent anemia (low number of red blood cells). For folate, the % DV shows how much folate in a serving of a food product contributes to a total daily diet. The % DV for folate helps determine if a serving of food is high or low in folate. For example, a serving of food or a supplement that contains 25% DV of folate means that one serving contributes to 25%, or one-quarter, of the folate needed in the daily diet.
- For most adults, 100% DV for folate is 400 micrograms dietary folate equivalents (DFE) or 400 mcg DFE. Women who are not pregnant or breastfeeding should consume 100% DV (400 mcg DFE per day) of folate to prevent anemia (low number of red blood cells). To prevent anemia, pregnant women and women who are breastfeeding should consume 600 mcg DFE and 500 mcg DFE, respectively, each day. Please see below for the recommended daily amount of folic acid to prevent neural tube defects.
- Folic acid is a type of folate, a B vitamin. Only folic acid is proven to help prevent neural tube defects (NTDs), which are severe birth defects of the brain or spine. To help prevent NTDs, CDC recommends that all women of reproductive age take 400 micrograms (mcg) of folic acid each day, in addition to consuming food with folate from a varied diet. It is easier for the body to form healthy cells using folic acid than using natural food folate.
- Folic acid can be measured in mcg DFE or in mcg (1.67 mcg DFE is the same as 1 mcg of folic acid). Based on this, to prevent anemia, women who are not pregnant or breastfeeding should consume 400 mcg DFE (100% daily value (DV) for folate), which is equal to 240 mcg folic acid. Because it takes more folic acid to help prevent NTDs than to prevent anemia (low number of red blood cells), 400 mcg folic acid is recommended to help prevent NTDs, which is equal to 667 mcg DFE (167% DV).
|To Prevent Anemia||400 mcg DFE||240 mcg folic acid||100%|
|To Prevent NTDs||667 mcg DFE||400 mcg folic acid||167%|
*% DV based on new Nutrition Facts and Supplement Facts labels starting January 1, 2021.
Yes, there has been a change in the % daily value (DV) for folate on new Nutrition Facts and Supplement Facts labels. Prior to January 1, 2021, micrograms of folic acid (mcg folic acid) was the unit of measure on the old Nutrition Facts and Supplement Facts labels. The old labels showed the % DV of folic acid contained in each serving—100% DV of folic acid was equal to 400 mcg of folic acid.
On the new Nutrition Facts and Supplement Facts labels, the unit of measure for folate is “mcg DFE,” or “micrograms of dietary folate equivalents.” In addition to the % DV, Nutrition Facts and Supplement Facts labels now show both the amount of folate in mcg DFE and mcg folic acid per serving. If any of the total amount of folate per serving comes from folic acid, the “mcg folic acid” will be listed in parentheses. For example, in the “New Label” shown below, the total folate contained in one tablet of the supplement is listed as “667 mcg DFE (400 mcg folic acid),” which indicates that 400 mcg of folic acid is part of the total amount of folate (667 mcg DFE) in one serving. The % DV of folate in the new labels is based on 400 mcg DFE, while the old label was based on 400 mcg of folic acid.
Only folic acid is proven to help prevent NTDs. In order to help prevent NTDs, women who are pregnant or planning to become pregnant should check the Nutrition Facts and Supplement Facts labels on supplements to make sure they are taking a supplement every day that contains 400 mcg of folic acid, in addition to eating foods with folate from a varied diet.