What is Folic Acid Used For? A Comprehensive Guide

December 31, 2025 •

4 min read

According to the CDC, fortification of cereal grains with folic acid has helped prevent thousands of neural tube defects since its mandated introduction in 1998. Folic acid, the synthetic form of vitamin B9, plays a vital role in countless bodily functions, from cellular growth to DNA synthesis. Understanding its purpose is key to maintaining overall health.

Quick Summary

Folic acid is a synthetic B vitamin used to prevent and treat folate deficiency, which can cause anemia. It is critical for pregnant women to prevent neural tube birth defects in the fetus and supports heart and brain health in adults.

Key Points

Essential for Cell Growth: Folic acid is required for the production of new, healthy cells and the synthesis and repair of DNA.
Prevents Birth Defects: Consuming adequate folic acid before and during early pregnancy significantly reduces the risk of neural tube birth defects like spina bifida.
Combats Anemia: It helps the body produce healthy red blood cells and prevents folate deficiency anemia, which can cause fatigue and weakness.
Supports Heart Health: By helping to regulate homocysteine levels, folic acid supports cardiovascular health and may reduce the risk of stroke.
Boosts Brain Function: Folic acid plays a role in brain health, mood regulation, and cognitive function, with potential benefits for mental well-being.
Mitigates Medication Side Effects: It is often used to counteract the side effects of certain medications, such as methotrexate.
Dietary Sources vs. Supplements: Folate is found naturally in foods like leafy greens and legumes, while folic acid is the more easily absorbed synthetic form found in fortified grains and supplements.

The Core Functions of Folic Acid

Folic acid, also known as vitamin B9, is a water-soluble vitamin essential for numerous physiological processes. It is vital for producing healthy new cells, making it particularly important during periods of rapid cell division and growth.

Cellular Growth and DNA Synthesis

At the most fundamental level, folic acid is a key component in the synthesis, repair, and methylation of DNA and RNA. This makes it indispensable for cell division and the production of all new cells in the body, including those for skin, hair, and blood. Without adequate folic acid, cells cannot divide properly, leading to a host of health problems.

Red Blood Cell Formation

Folic acid works with vitamin B12 to create healthy red blood cells. A deficiency in either can lead to megaloblastic anemia, a condition characterized by abnormally large, poorly functioning red blood cells. This can result in symptoms like fatigue, weakness, and shortness of breath.

Folic Acid's Crucial Role in Pregnancy

Folic acid is perhaps most well-known for its significance during pregnancy. Its importance lies in preventing neural tube defects (NTDs), which are major birth defects of the baby's brain and spine, such as spina bifida and anencephaly.

Prevents Neural Tube Defects: Since the neural tube develops and closes very early in pregnancy, often before a woman knows she is pregnant, it is recommended that all women of childbearing age consume 400 micrograms (mcg) of folic acid daily.
Supports Fetal Development: Beyond the neural tube, sufficient folic acid helps ensure the overall healthy development of the fetus during this crucial growth phase.
Reduces Risks: Adequate folic acid intake may also help reduce the risks of other complications, including preterm birth and low birth weight.

Benefits for Broader Health

While critical for prenatal health, the uses of folic acid extend far beyond pregnancy, impacting multiple aspects of adult health.

Heart Health

High levels of the amino acid homocysteine have been linked to an increased risk of heart disease and stroke. Folic acid, along with other B vitamins, helps break down homocysteine, keeping levels in check and supporting cardiovascular health. Studies have shown that folic acid supplementation can help lower homocysteine levels.

Brain and Cognitive Function

Folate plays an essential role in brain health and mood regulation.

Neurotransmitter Production: Folate is necessary for creating neurotransmitters, which are essential for mood stability. Deficiency can impair this process, contributing to anxiety and depression.
Cognitive Support: Some research suggests that folic acid, especially in combination with other B vitamins, can support memory and thinking skills, particularly in older adults with low B12 levels.

Other Uses and Conditions

Methotrexate Toxicity: Folic acid is often prescribed alongside the medication methotrexate to help mitigate its side effects, which can include nausea and mouth sores, by preventing a folate deficiency.
Male Fertility: Some studies indicate that folic acid supplementation, particularly when combined with zinc, may improve semen quality and support normal sperm development in men.
Depression: For some individuals, especially those with low folate levels, supplementing with folic acid can enhance the effects of antidepressant medication.

Folate vs. Folic Acid: What is the difference?

It is important to distinguish between folate and folic acid, though the terms are often used interchangeably.


Feature	Folate	Folic Acid
Definition	The naturally occurring form of vitamin B9 found in food.	The synthetic (man-made) form of vitamin B9 used in supplements and fortified foods.
Absorption	Less stable and may be more difficult for the body to absorb effectively.	More stable and absorbed by the body more easily and efficiently.
Sources	Leafy green vegetables, legumes, citrus fruits, eggs, liver.	Fortified foods like bread, pasta, and cereals, plus supplements.
Usage	Primarily obtained through a balanced diet.	Recommended for those who are or may become pregnant, or have a diagnosed deficiency.
Fortification	Not added to food products in the same way.	Added to many grain products in the U.S. and other countries to help prevent deficiencies.

Potential Risks and Considerations

While generally safe at recommended dosages, excessively high intakes of folic acid can pose risks, especially for individuals with a vitamin B12 deficiency. This is because high doses of folic acid can mask the symptoms of a vitamin B12 deficiency, potentially leading to irreversible nerve damage if the underlying condition goes untreated. It is crucial to consult a healthcare provider before taking high-dose folic acid supplements.

Conclusion

Folic acid is a powerful and versatile B vitamin with a wide range of essential uses, most notably its crucial role in preventing serious birth defects and supporting cellular health. From treating anemia and supporting cardiovascular health to boosting brain function and mitigating medication side effects, its benefits are far-reaching. By understanding the distinction between natural folate and synthetic folic acid and incorporating sufficient sources into their diet, individuals can actively support their overall well-being. Always consult a healthcare professional to determine the appropriate dosage for your specific needs, especially if you are pregnant, trying to conceive, or have other health conditions.

For more information on nutrition during pregnancy, visit the CDC's guidelines on the topic.

Frequently Asked Questions

Folic acid's primary function is to help the body produce and maintain new, healthy cells. It is essential for DNA synthesis and repair, making it critical for proper cell division and growth.

Folic acid is critical during early pregnancy to help prevent serious birth defects of the baby's brain and spine, known as neural tube defects (NTDs), such as spina bifida.

For adults, the Recommended Dietary Allowance (RDA) for folate is 400 micrograms (mcg) per day. Women who are pregnant or planning to become pregnant are advised to increase their intake.

Symptoms of folic acid deficiency often include fatigue, weakness, pale skin, irritability, and a sore or red tongue. It can lead to a type of anemia called megaloblastic anemia.

Yes, men can also benefit from folic acid. It helps with healthy red blood cell production, supports heart health by lowering homocysteine levels, and plays a role in male fertility.

High doses of folic acid can mask a vitamin B12 deficiency, potentially leading to nerve damage if left untreated. It is also linked to potential side effects like nausea, gas, and confusion at very high doses. Consult a doctor before taking large amounts.

Foods rich in natural folate include leafy green vegetables (like spinach and kale), asparagus, broccoli, legumes (beans and lentils), citrus fruits, and eggs. Fortified foods like cereals and bread are also key sources of folic acid.