What is the major function of folate?

October 29, 2025 •

3 min read

According to the CDC, folate plays a critical role in producing DNA and other genetic material, which are the building blocks of the human body. The major function of folate, also known as vitamin B9, is its essential involvement in a series of biochemical reactions that are foundational to human life and health.

Quick Summary

Folate's major function involves one-carbon metabolism, supporting DNA and RNA synthesis, cell division, and red blood cell formation. It is crucial for rapid tissue growth, notably during pregnancy, and for regulating homocysteine levels to promote cardiovascular and neurological health.

Key Points

DNA Synthesis: The primary role of folate is to act as a coenzyme in one-carbon metabolism, which is critical for synthesizing the DNA building blocks (purines and pyrimidines).
Cell Division and Growth: By enabling DNA replication, folate is essential for cell division and rapid tissue growth, especially during fetal development, infancy, and adolescence.
Red Blood Cell Formation: Folate works with vitamin B12 to produce and mature healthy red blood cells, with deficiency leading to megaloblastic anemia.
Homocysteine Metabolism: It helps convert homocysteine to methionine, preventing high levels of homocysteine that are associated with cardiovascular disease and neurological problems.
Prevention of Neural Tube Defects: Adequate intake of folic acid before and during early pregnancy is crucial for preventing birth defects of the brain and spine, such as spina bifida.
Brain and Nervous System Health: Folate supports neurotransmitter formation and nervous system health throughout life, with deficiency linked to mood changes and cognitive decline.

Folate's Central Role in DNA and Cell Division

At the most fundamental level, the major function of folate is its role in one-carbon metabolism, a process that is essential for life. As a coenzyme, the active form of folate, tetrahydrofolate (THF), helps carry single-carbon units to be used in various biosynthetic pathways. This metabolic activity is indispensable for the synthesis of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), the blueprints of our genetic code.

The Process of Nucleic Acid Synthesis

Within the cell, folate derivatives are critical for producing the purine and pyrimidine bases that make up DNA. Specifically, folate donates carbon units needed for creating adenine, guanine, and thymine. Without sufficient folate, DNA replication is hampered, and cell division slows or stops altogether. This impact is most severe in tissues that undergo rapid cell proliferation, such as bone marrow, where red blood cells are formed. This explains why a folate deficiency can lead to megaloblastic anemia, a condition characterized by abnormally large, immature red blood cells.

Critical Importance During Periods of Rapid Growth

The major function of folate becomes especially pronounced during periods of rapid growth and development.

Pregnancy and Fetal Development: Adequate folate intake is critically important before and during early pregnancy. Its role in DNA synthesis and cell division directly impacts the development of the fetal neural tube. A deficiency during this crucial period can lead to serious birth defects, such as spina bifida and anencephaly. Health organizations globally recommend that women of childbearing age take folic acid supplements to prevent these outcomes.

Infancy and Childhood: As infants and children grow, their bodies require a steady supply of folate to support cell proliferation and tissue formation. Folate is necessary for healthy brain development and overall growth during these formative years.

Folate's Function in Red Blood Cell Formation

Folate works closely with vitamin B12 to ensure the proper formation and maturation of red blood cells in the bone marrow. A deficiency in either nutrient disrupts this process, leading to the production of large, immature red blood cells and ultimately causing megaloblastic anemia. This condition is marked by symptoms such as fatigue, weakness, and shortness of breath due to the reduced oxygen-carrying capacity of the blood.

Metabolism of Homocysteine

Beyond its role in cell growth, another significant function of folate is its involvement in the metabolism of the amino acid homocysteine.

The Methylation Cycle: Folate acts as a methyl group donor in the conversion of homocysteine to methionine, a critical step in the methylation cycle.
Cardiovascular Health: High levels of homocysteine in the blood are associated with an increased risk of cardiovascular disease and stroke. By helping to regulate homocysteine, folate supports heart and vascular health.
Brain Function: Elevated homocysteine has also been linked to cognitive impairment, dementia, and Alzheimer's disease. While research on supplementation and prevention is ongoing, folate's role in methylation is vital for healthy brain function and memory.

Comparison: Folate vs. Folic Acid


Feature	Folate	Folic Acid
Source	Naturally occurring in foods like leafy greens, legumes, and fruits.	Synthetic form used in dietary supplements and fortified foods.
Absorption	Less stable and absorbed less efficiently by the body compared to folic acid.	More stable and has a higher bioavailability, meaning it is better absorbed.
Purpose	Provides general nutritional support from whole foods.	Primarily used for supplements and fortifying foods to prevent neural tube defects and address deficiencies.
Regulation	Levels depend on dietary intake and cooking methods.	Intake is regulated in fortified foods, ensuring consistent availability.

Conclusion: The Unwavering Importance of Folate

In conclusion, the major function of folate is its indispensable role in facilitating one-carbon metabolism, which is the biochemical foundation for DNA synthesis, cell division, and healthy cell growth. This function is critical throughout the human lifespan, from fetal development to supporting cardiovascular and neurological health in adulthood. The importance of adequate folate intake is evident in its ability to prevent serious birth defects, aid in red blood cell production, and regulate harmful homocysteine levels. Whether obtained through natural dietary sources or synthetic fortification, a sufficient supply of folate is fundamental for maintaining overall health and well-being. For those with specific health concerns, understanding these functions underscores why a doctor might recommend monitoring folate levels or taking supplements.

Visit the National Institutes of Health for more information on folate.

Frequently Asked Questions

Folate is the naturally occurring form of vitamin B9 found in foods like leafy greens, while folic acid is the synthetic, man-made version used in supplements and fortified foods. Folic acid is generally more stable and better absorbed by the body.

Folate is a crucial coenzyme required for the synthesis of new red blood cells in the bone marrow. Working alongside vitamin B12, it ensures these cells develop and mature correctly. A deficiency impairs this process, leading to megaloblastic anemia.

During early pregnancy, folate is critical for the proper formation of the neural tube, which develops into the baby's brain and spinal cord. Sufficient folate intake can significantly reduce the risk of neural tube defects, such as spina bifida.

A folate deficiency can lead to megaloblastic anemia, causing symptoms like fatigue, weakness, and shortness of breath. Other potential signs include mouth sores, changes in skin and hair, and neurological issues.

While folate from food sources is not harmful, excessive intake of synthetic folic acid, particularly in high doses, can mask a vitamin B12 deficiency. It is important to discuss supplementation with a healthcare provider, especially for older adults.

Good natural sources of folate include dark leafy green vegetables (spinach, asparagus), legumes (beans, peas), citrus fruits, eggs, and nuts. Many grains and cereals in some countries are also fortified with folic acid.

Folate helps the body break down homocysteine, an amino acid. High levels of homocysteine are linked to an increased risk of cardiovascular disease. By regulating homocysteine, folate helps maintain vascular health and may reduce stroke risk.