What is folic acid?

Folic acid , also known as vitamin B9 , is a water-soluble B-complex vitamin that plays a crucial role in cell division, DNA synthesis, blood formation, and tissue growth . In its natural form—found in foods—it is called folate , while folic acid is the synthetic, particularly stable form used in supplements and fortified foods.

The name derives from the Latin word folium (leaf), as folate was first discovered in green leafy vegetables. Good natural sources include spinach, broccoli, kale, asparagus, legumes, oranges, whole grains, and liver.

Folic acid is essential for growth, cell regeneration, and the development of the nervous system – especially during pregnancy, as it supports the formation of the neural tube in the unborn child. A deficiency can have serious consequences, which is why folic acid is one of the most important vitamins.

How does folic acid work?

After ingestion, folic acid is converted into its active form tetrahydrofolate (THF) , which acts as a coenzyme in a variety of vital processes.

Cell division and DNA synthesis:
Folate is necessary for the formation of nucleic acids (DNA and RNA) – the genetic building blocks of every cell. Without sufficient folic acid, the body cannot form new cells, which is particularly critical during periods of rapid growth – such as during pregnancy, childhood, or tissue regeneration.

Blood formation:
Together with vitamin B12, folic acid is crucial for the maturation of red blood cells. A deficiency leads to a condition called megaloblastic anemia , in which large, dysfunctional blood cells develop, causing fatigue, paleness, and difficulty concentrating.

Protection of the nervous system and homocysteine ​​reduction:
Folic acid, together with vitamins B6 and B12, lowers the level of the amino acid homocysteine , which, in excess, damages blood vessel walls and promotes cardiovascular disease. In this way, it indirectly contributes to heart health and vascular elasticity .

Pregnancy and development:
Adequate folic acid intake is crucial for embryonic development during pregnancy. It reduces the risk of serious birth defects such as neural tube defects (e.g., spina bifida) by up to 70%. Therefore, women planning a pregnancy are advised to take 400 µg of folic acid daily, even before conception .

Skin, hair and tissue:
Since folic acid promotes cell division and regeneration, it also has a positive effect on skin renewal, hair growth and wound healing .

Benefits of folic acid

  • Supports cell division and the growth of new cells

  • Promotes DNA and RNA synthesis

  • Supports the formation of red blood cells and prevents anemia.

  • Protects heart and blood vessels through homocysteine ​​regulation

  • Essential for a healthy pregnancy and the development of the nervous system in the fetus

  • Supports skin, hair and tissue regeneration

  • Promotes mental performance and concentration

Possible side effects and interactions

Folic acid is generally very well tolerated. Because it is water-soluble, excess amounts are excreted in the urine. However, in very high doses (over 1000 µg per day), folic acid can mask a vitamin B12 deficiency , as it corrects anemia but does not prevent neurological damage. Therefore, combined intake with vitamin B12 is recommended at higher doses.

A deficiency in folic acid can be caused by an unbalanced diet, alcohol, stress, certain medications (e.g. birth control pills, methotrexate, antiepileptics) or increased cell division rates.

Conclusion

Folic acid is a vital vitamin for growth, blood formation, and cell health. It ensures smooth cell division, protects the cardiovascular system, and is essential for a healthy pregnancy. Since it is often lacking in many modern diets, women of childbearing age, older people, and individuals with elevated stress levels particularly benefit from targeted folic acid intake – ideally in combination with vitamins B12 and B6 for a holistic effect on cells, blood, and nerves.

Sources

  1. Bailey LB, Gregory JF. (1999): Folate metabolism and requirements. J Nutr , 129(4), 779–782.

  2. Lucock M. (2000): Folic acid: nutritional biochemistry, molecular biology, and role in disease processes. Mol Genet Metab , 71(1–2), 121–138.

  3. Blom HJ, Shaw GM, den Heijer M, Finnell RH. (2006): Neural tube defects and folate: case far from closed. Nat Rev Neurosci , 7(9), 724–731.

  4. Selhub J. (2002): Folate, vitamin B12 and vitamin B6 and one carbon metabolism. J Nutr Health Aging , 6(1), 39–42.