Folic acid is necessary for cell development; for the metabolism of specific biochemical reactions in the body, such as the conversion of homocysteine to methionine; and for the metabolism of specific anticonvulsant drugs. Folic acid has an interrelationship with vitamin B12. A deficiency of folate increases the risk of NTDs, as well as contributing to hyperhomocystinemia, a condition associated with increased cardiovascular disease and NTDs. For the prevention of NTDs, it is recommended that a woman of childbearing age consume a daily folate intake of 400 micrograms; however, the average dietary folate intake is half that amount, and the FDA folate fortification of cereal grains adds only 100 micrograms daily. The woman in her childbearing years does not meet the recommendation with dietary and food fortification. Periconceptional folic acid supplementation is essential, because the neural tube closes 23 to 27 days after conception. Therefore, a multiple vitamin containing folic acid is the practical solution at present if the food fortification is not increased. The bioavailability of folate in the vitamin preparation is approximately double that of dietary folate. Most preparations contain 400 micrograms of folic acid, and if the woman took a multiple vitamin (400 micrograms of folate) in addition to her diet (230 micrograms of folate), she would not exceed 1000 micrograms (1 mg) daily, which is considered the upper limit of daily folate ingestion by dietary fortification and supplementation before the masking of vitamin B12 becomes a concern. However, in this group of patients, pernicious anemia is rare. Regarding cardiovascular disease in men and women, there are no long-term studies showing the benefit of folic acid in reducing the homocysteine level. At present, there are only estimations. However, they should not be ignored. Although it is not the current standard of practice, adding a multiple vitamin containing folic acid to the regimen of men and women starting anticonvulsant medication should be considered in order to prevent the folate lowering observed with such commonly used drugs as PHT and carbamazepine. Women in childbearing years should be on a folic acid supplement when taking an anticonvulsant drug. In general, it appears that all men and women would benefit from increased folate intake. This can be accomplished through vitamin supplementation when there is compliance. However, if the food fortification for folate is increased in the future, then the issue of vitamin supplementation will have to be readdressed.
It is really important to take folic acid if you are planning on getting pregnant.
So you’ve started to think about trying for a baby, congratulations, what an exciting time!
Good nutrition is important for everyone, but particularly important for pregnant women for healthy growth and development of their baby.
It is important to get enough nutrients and vitamins before conception and during pregnancy.
Folic acid supplements are recommended for women who are planning to become pregnant, could become pregnant or are pregnant.
What is folic acid?
Folic acid is the man-made form of the B vitiamin folate.
Folic acid is added to some foods and can also be found in supplements. If you are planning on getting pregnant or are in the early stages of pregnancy, it’s best to take a daily folic acid supplement, as well as eat high-folate foods. Folate is found naturally in food like leafy green vegetables, citrus fruit, legumes and nuts. Folate is water-soluble and is easily destroyed by cooking.
What does folic acid do?
Folic acid is vital for healthy bodily growth and development in everyone and is especially important for pregnant women. Your body uses folic acid to make DNA. If you’re pregnant, folic acid is needed to help the development of your baby’s nervous system and neural tube early in pregnancy.
What is a neural tube?
The neural tube is one of the first things your baby will grow. It will become your baby’s brain and spinal cord and the bones that enclose them. The neural tube is formed in the first four to six weeks of pregnancy.
A neural tube defect can happen when something goes wrong in the development of a baby’s neural tube. This can cause a range of disabilities including loss of bladder and bowel control, and paralysis of the legs. In some cases, the effects can be more severe.
What is spina bifida?
Spina bifida is a neural tube birth defect that occurs when a baby’s spine and spinal cord don’t form properly.
It is unclear what causes spina bifida but it can be linked to a combination of genetic and environmental risk factors, for example a family history of neural tube defects and folate deficiency.
Signs and symptoms of spina bifida vary by type and severity and can also differ per person.
Most spina bifida cases are detected with an ultrasound scan around 18 weeks of pregnancy.
Can I prevent my baby getting spina bifida?
The best way to reduce the risk of your baby developing a neural tube defect is to take daily folic acid supplements from 12 weeks before conception until at least 12 weeks of pregnancy. Researach shows that taking a daily folic acid supplement of 400 micrograms reduces the risk of your baby developing spina bidifa and similar birth defects by up to 70%.
Why do I need to take folic acid when pregnant?
When you’re pregnant you need more folic acid to help your baby grow. Adding a folic acid supplement to your diet when pregnant reduces the risk of your baby being born with a neural tube defect.
How much folic acid do I need to take?
You should take a supplement with 400 micrograms of folic acid per day from 12 weeks before you become pregnant through to the first 12 weeks of pregnancy. Folic acid supplements are available over the counter from pharmacies at varying doses. Look for supplements that contain at least 400 micrograms of folic acid. Multi-vitamin supplements generally contain less.
It is also important to eat healthy foods that contain folate including green leafy vegetables, broccoli, oranges, avocado, or fortified breads and cereals. You can read more about what foods to eat when pregnant here.
You should talk to your doctor, pharmacist or a dietitian before starting to take any new supplements.
Are there risks from taking folic acid?
Generally when taken orally, and at appropriate doses, folic acid is safe. If you take too much folic acid your body gets rid of any excess in your urine.
Some people may experience minor side effects from taking folic acid supplements such as:
- Bad taste in the mouth
- Nausea
- Loss of appetite
- Confusion
- Irritability
- Sleep pattern disturbance.
Signs of an allergic reaction to folic acid include:
- Skin rash
- Itching
- Redness
- Difficulty breathing.
If you think you are having a severe allergic reaction call 000 immediately.
If you have any other symptoms suggesting an allergic reaction or concerns about allergies please contact one of our Registered Nurses at 13 HEALTH by phoning 13 43 25 84.
When should I start taking folic acid?
It is recommended that women of child-bearing age, even those who are not planning to have a baby take folic acid supplements, as half of all pregnancies are unplanned. A baby’s growth is the most rapid in the first weeks of life – often before you are aware you are pregnant.
Last updated: 24 October 2018
Written by Stephanie Watson — Medically reviewed by Imashi Fernando, MS, RDN — Updated on April 5, 2022
Folic acid is a water-soluble vitamin. It’s a synthetic version of folate, one of the B vitamins (1).
Because your body can’t make folate, you need to get it from your diet.
Some foods naturally contain folate. Folic acid is added to other foods. You can also get folic acid from dietary supplements (2).
What’s the difference between folate and folic acid?
Although the terms “folate” and “folic acid” are often used interchangeably, they are actually different forms of the same vitamin: vitamin B9.
Folic acid has a different structure than folate and has slightly different effects in your body. “Folate” is the generic name that encompasses all forms of vitamin B9, including folic acid and 5-MTHF. Folic acid is a specific synthetic form of this vitamin (1, 2, 3).
You can find folate in plant and animal foods like these (1):
- spinach
- kale
- broccoli
- avocado
- citrus fruits
- eggs
- beef liver
Folic acid is added to foods such as flour, ready-to-eat breakfast cereals, and breads (4, 5).
It’s also in dietary supplements, such as multivitamins (1, 4).
What does the body use folate for?
Your body uses folate to (1):
- make and repair DNA
- help cells grow, divide, and work properly
- produce certain proteins
- help red blood cells mature
Folate deficiency can lead to many health problems, including (1, 2, 6, 7):
Many countries, including the United States, require certain grain products to be fortified with folic acid. Folic acid fortification helps prevent neural tube irregularities in infants (7, 8).
SummaryFolic acid is a synthetic version of the B vitamin folate, which naturally occurs in leafy greens, eggs, and citrus fruits, among other foods. It’s essential to important functions in the body.
The Recommended Dietary Allowance (RDA) for folate is listed in Dietary Folate Equivalents (DFEs). This unit of measure accounts for the differences in how your body absorbs folate from foods and folic acid from fortified foods and supplements.
Your body absorbs natural folate about half as well as folic acid from supplements (1).
Adults need about 400 mcg DFE of folate each day. During pregnancy and breastfeeding, folate needs can increase. The RDA during pregnancy is 600 mcg DFE (1, 6, 7, 9).
Your body stores 15–30 mg of folate. Most of that folate is in your liver, and the rest is in your blood and tissues (1).
The RDA for folate for infants, children, and teens is (1):
- Birth to 6 months: 65 mcg DFE
- Ages 7–12 months: 80 mcg DFE
- Ages 1–3: 150 mcg DFE
- Ages 4–8: 200 mcg DFE
- Ages 9–13: 300 mcg DFE
- Ages 14–18: 400 mcg DFE
SummaryAdults need about 400 mcg DFE of folate each day.
Both folic acid and folate are used in supplements. Although these two nutrients treat the same conditions, they are metabolized differently in the body and can affect health in different ways (1).
Here are some common uses and benefits of folic acid supplements.
Treating folate deficiency
Folate deficiency can happen for many reasons. Some possible causes of folate deficiency are (1, 2):
Consuming too little folate can cause complications such as anemia, fetal development issues, mental impairment, impaired immune function, and depression. Taking folic acid or folate supplements can bring up your levels and prevent these complications (6, 7, 9, 10).
Preventing birth defects and pregnancy complications
Folic acid supplements can help to prevent neural tube irregularities, including spina bifida and anencephaly. Getting enough folic acid during pregnancy can reduce the chance that your baby will be born with one of these conditions (7, 9).
Folic acid supplements not only help prevent fetal development issues but also help lower the risk of pregnancy complications such as preeclampsia (10).
Maintaining brain health
Low blood folate levels are linked to poor mental function and an increased risk of dementia. Even folate levels that are technically normal but on the low side might increase the risk of mental impairment in older adults.
Adequate folate intake may also help protect against Alzheimer’s disease (11, 12).
In a 2019 study in 180 adults with mild cognitive impairment, taking 400 mcg of folic acid supplements daily for 2 years improved measures of brain function and reduced blood levels of proteins that are involved in Alzheimer’s disease (13).
Another study looked at 121 people with newly diagnosed Alzheimer’s disease who were being treated with the medication donepezil (Aricept).
Those who also took 1,250 mcg of folic acid per day for 6 months had improved thinking ability and less inflammation than those who took Aricept alone (14).
Treating mental health conditions
Folate is involved in the production of brain chemicals called neurotransmitters. Consuming too little folate has been linked to depression, schizophrenia, and other mental health conditions.
For example, people with depression may have lower blood levels of folate than people without depression (15).
A 2022 review of studies suggests that folic acid and folate supplements may help reduce symptoms of mental health conditions such as postpartum depression, schizophrenia, and bipolar disorder (16).
Taking folate supplements in addition to antidepressant medication may reduce depression symptoms more than taking antidepressant medication alone (17).
A review of seven studies found that treatment with folate supplements plus antipsychotic medication may improve symptoms in people with schizophrenia more than antipsychotic medication alone (18).
However, larger, more robust studies are needed to further support these findings.
Reducing heart disease risk factors
Folate-based supplements, including folic acid, may help improve heart health and reduce the risk of heart disease.
High levels of the amino acid homocysteine are thought to increase heart disease risk. Because folate helps break down homocysteine, low folate can lead to high homocysteine levels, also known as hyperhomocysteinemia.
Folic acid supplements can help bring down homocysteine levels and may lower heart disease risk (19).
For example, a review that included 30 studies with more than 80,000 total participants showed that supplementing with folic acid led to a 4% reduction in overall heart disease risk and a 10% reduction in stroke risk (19).
What’s more, using folic acid supplements along with antihypertensive medications may reduce high blood pressure significantly more than antihypertensive medications alone. Folic acid supplements may also improve blood vessel function in people with heart disease (20, 21).
Other possible benefits
Folic acid supplements may also help with these other health conditions:
- Diabetes. Folate supplements may help improve blood sugar regulation and reduce insulin resistance in people with diabetes. Because the diabetes drug metformin can lower folate levels, you may need a supplement if your levels are low (22, 23, 24).
- Fertility issues. Folate can improve egg quality and help eggs grow and implant in the uterus. Taking folate may increase the chance of getting pregnant and carrying a baby to term. People who use assisted reproductive technology to conceive may be more likely to have a baby if they have a higher intake of supplemental folate (25, 26).
- Inflammation. Inflammation plays a role in many diseases. Folic acid and folate supplements have been shown to reduce markers of inflammation such as C-reactive protein (27).
- Kidney disease. The kidneys usually filter waste out of the blood, but when the kidneys are damaged, homocysteine can build up. About 85% of people with chronic kidney disease have too much homocysteine in their blood. Folic acid supplements may help reduce homocysteine levels and heart disease risk in people with kidney disease (28).
Larger studies are still needed to confirm the benefits of folate supplementation.
This list doesn’t include every possible benefit of folic acid. There are many other reasons people may use folate-based supplements.
SummaryFolic acid supplements are commonly used to prevent fetal development issues in pregnant people. Low levels of folate can be associated with health risks, and a deficiency of this essential nutrient may be caused by a medical condition.
Folate plays essential roles in a baby’s development.
It’s involved in cell division and tissue growth. It also helps the baby’s brain and spine, called the neural tube, develop. Taking folic acid both before and during pregnancy can help prevent neural tube irregularities such as anencephaly and spina bifida (1, 7, 8).
The U.S. Preventive Services Task Force, an independent panel of national disease-prevention experts, recommends that anyone who is trying to become pregnant start taking a daily folic acid supplement containing 400–800 mcg at least 1 month before becoming pregnant and through the first 2–3 months of pregnancy (9).
However, the common recommendation in practice encourages people capable of getting pregnant — of childbearing age and engaging in sexual activity that could result in pregnancy — to take a folic acid supplement, because many pregnancies can be unplanned (6, 7, 9).
Since the 1990s, flour and other foods have been fortified with folic acid. Consuming both fortified foods and folic acid supplements before and during pregnancy can help reduce the risk of neural tube irregularities (5, 7, 8).
Beyond preventing fetal development issues, taking folic acid supplements during pregnancy may improve a child’s mental function and reduce the chance of the child developing autism spectrum disorder (ASD).
However, taking too much folic acid may have a negative effect on a child’s brain development and increase their chances of developing autism, which will be discussed in the next section (29).
Folate is also important for the health of the pregnant person. Supplementing with folic acid has been shown to reduce the risk of pregnancy-related complications, including preeclampsia. Higher folate levels in a pregnant person may lower the risk of preterm birth (10, 30).
Folate is important for the health of both pregnant people and their babies, and it’s not always easy to get enough of this nutrient through your diet alone (6, 7, 9).
SummaryFolic acid supplements help support pregnancy, reduce pregnancy-related complications, and reduce the chance of fetal development issues.
When you take folic acid, your liver has to convert it into the active form, 5-methyltetrahydrofolate (5-MTHF).
If your liver doesn’t convert it quickly enough, folic acid can build up in your blood. Eating foods containing 5-MTHF instead of folic acid can prevent this from happening (1).
Foods that contain 5-MTHF include (1):
- leafy greens
- beans and lentils
- asparagus
- avocado
Certain gene changes affect how your body uses folate. Methylenetetrahydrofolate reductase (MTHFR) is an enzyme that breaks down homocysteine. Changes called mutations in the code for MTHFR can affect your health by changing folate levels in your body (2).
One of the most common mutations to MTHFR is C677T. People with this variant have less activity of an enzyme that breaks down homocysteine. They may have high levels of homocysteine, which could increase their heart disease risk.
In a pregnant person, this variant can also increase the chance of neural tube irregularities in a developing fetus (2, 31).
There are genetic tests for MTHFR variants, but few people need them.
Having an MTHFR mutation alone doesn’t mean you’re at risk of health problems or that you need treatment. But if your homocysteine levels are high, a healthcare professional may recommend that you take a supplement (31).
SummaryCertain genetic mutations may affect the folate levels in your body.
Eating folate-rich foods and taking natural forms of folate such as 5-MTHF are generally considered safe. But taking high doses of folic acid through supplements could potentially lead to a buildup of unmetabolized folic acid in your blood.
“Unmetabolized” means your body hasn’t broken down the folic acid or converted it into other forms of folate. No confirmed health risks due to unmetabolized folic acid have yet been found, but undiscovered risks may still exist (1, 32, 33, 34, 35).
It’s important to note that most children and adults in the United States get enough folate from food and don’t need to take a folic acid supplement (1).
Autism
Taking folic acid during pregnancy helps prevent neural tube irregularities. But having high levels of unmetabolized folic acid in your blood may increase the chance that your child will have ASD.
People who take less than 400 mcg of folic acid daily are unlikely to have high levels of unmetabolized folic acid in their blood (29, 36).
High levels of unmetabolized folic acid during pregnancy may affect children’s mental development.
In a study of 1,682 mother-child pairs, children whose mothers supplemented with more than 1,000 mcg of folic acid per day during pregnancy scored lower on a test of mental abilities than children whose mothers took 400–999 mcg per day (37).
Although these studies suggest there may be risks to taking high doses of folic acid during pregnancy, more research is needed to confirm these findings.
Other possible risks of high folic acid intake
Taking high doses of folic acid may be associated with other health conditions, including the following.
Cancer
Folic acid might lower the risk of cancers affecting the head and neck, pancreas, esophagus, and bladder. But it may increase the risk of prostate cancer.
So far, research on the topic has not delivered conclusive results, and more studies are needed.
But research suggests that folate may suppress some types of cancer during its early stages, while high doses of folic acid taken after precancerous cells have developed may cause cancer to grow and progress (1, 38, 39).
Impaired immune function
High dose folic acid supplements may suppress the immune system by reducing the activity of protective immune cells such as natural killer (NK) cells. Whether these immune changes could put people at increased risk of infection is still unknown (40).
SummaryResearch has suggested that high folic acid intake may be associated with certain health conditions, including cancer, autism, and immune system suppression.
Folate and folic acid can be found in many forms. They are added to multinutrient supplements, including multivitamins and B-complex vitamins. Most adult supplements contain 680–1,360 mcg DFE (400–800 mcg of folic acid) (1).
The Tolerable Upper Intake Level (UL) is the highest daily folic acid dose you can take without experiencing harmful side effects.
The UL includes only folate from fortified foods and dietary supplements. High intake of naturally occurring folate from food has not been shown to cause any adverse effects (1).
The UL for folate in supplements and fortified foods is (1, 32):
Most children in the United States get enough folate from food, and 30–66% of children ages 1–13 who take folic acid supplements exceed the UL for their age group. Ask a pediatrician before giving your child a folic acid supplement to make sure it’s safe (1).
You can take all forms of folic acid with or without food.
Before taking folic acid
A healthcare professional might recommend a folic acid supplement if you have a deficiency or you are pregnant or thinking about getting pregnant.
Let a healthcare professional know what other prescription and over-the-counter medications you take. Folic acid may interact with some medicines (1).
Storage and handling
Store folic acid supplements in a cool, dry place. Keep supplements away from humid areas, such as the bathroom.
Overdose
There’s no set upper limit for folate in foods. Because folate is water-soluble, your body removes any extra you consume. Still, it may be possible to develop side effects if you take folic acid supplements in amounts greater than the UL (1, 2).
A healthcare professional may recommend higher doses if you have a folate deficiency. Avoid taking more than the UL unless a healthcare professional directs you to do so.
SummaryThe maximum amount of folic acid and folate adults can consume from supplements and fortified foods without experiencing harmful side effects is 1,000 mcg. Children typically get enough folate from food alone.
Folic acid supplements may interact with some commonly prescribed medications, including (1):
- methotrexate, which is used to treat some cancers and autoimmune diseases
- epilepsy medications such as phenytoin (Dilantin), carbamazepine (Carbatrol, Tegretol, others), and valproate (Depacon)
- sulfasalazine (Azulfadine), which is used to treat ulcerative colitis
If you’re taking one of these medications, ask your doctor before taking folic acid supplements.
SummaryFolic acid supplements may interact with some medications.
Folate supplements are especially important for people who (1, 2):
- are pregnant or of childbearing age
- have a condition that affect folate absorption, such as celiac disease or inflammatory bowel disease
- have gene changes that affect how their bodies break down and use folate
- are older and live in care facilities
- are at higher risk of folate deficiency because of their diet
- have alcohol use disorder
Avoid giving folate supplements to infants under 1 year old unless a healthcare professional recommends it. Breastmilk, formula, and food should be the only sources of folate in an infant’s diet (1).
SummaryPeople who are pregnant or of childbearing age or who have folate deficiencies often use folic acid supplements.
There are many versions of folate. Folinic acid, folic acid, and 5-methyltetrahydrofolate are the ones most widely used in dietary supplements (1).
Folinic acid is a natural form of folate found in foods. Healthcare professionals call it leucovorin. It’s used to prevent toxic side effects from the drug methotrexate, which is a treatment for some types of cancer (41).
Folinic acid is more effective than folic acid at raising blood folate levels (41).
Some studies have shown that 5-MTHF absorbs better than other forms of synthetic folate. Plus, it’s less likely to interact with medications. This suggests it may be better to take 5-MTHF supplements than folic acid. However, other studies have found no significant differences (42).
SummaryFolinic acid, folic acid, and 5-methyltetrahydrofolate (5-MTHF) are the types of folate most commonly used in dietary supplements.
Last medically reviewed on April 5, 2022