What is the role of Folic acid (Vitamin B9)?

From the Guidelines

Folic acid (Vitamin B9) plays a crucial role in preventing neural tube defects and possibly reducing the occurrence of other birth defects, and its supplementation is essential for women of childbearing age, particularly those planning pregnancy or in their first trimester. The recommended daily intake of folic acid varies, but for women without a prior history of neural tube defects (NTDs), a dose of 400 to 5000 micrograms (0.4-5 mg) per day has been shown to reduce the incidence and recurrence of NTDs by 40% to 100% 1. Key points to consider include:

• Folic acid supplementation should be taken at least 1 month before conception and throughout the first trimester to ensure maximum benefit, as neural tube closure occurs within the first 28 days after conception 1.
• Women with a prior history of NTDs should also take folic acid supplementation, as all published studies reported a similar reduction in NTDs after supplementation 1.
• The dose of folic acid can vary, but 400 to 5000 micrograms (0.4-5 mg) per day is the recommended range, and it can be taken alone or as part of a multivitamin preparation 1.
• It is essential for women of childbearing age to maintain adequate daily folic acid intake throughout their reproductive years, as many pregnancies are unplanned, and neural tube closure occurs before the recognition of pregnancy 1.

From the FDA Drug Label

Folic acid acts on megaloblastic bone marrow to produce a normoblastic marrow. In man, an exogenous source of folate is required for nucleoprotein synthesis and the maintenance of normal erythropoiesis Folic acid is a precursor of tetrahydrofolic acid, which is involved as a cofactor for transformylation reactions in the biosynthesis of purines and thymidylates of nucleic acids Impairment of thymidylate synthesis in patients with folic acid deficiency is thought to account for the defective deoxyribonucleic acid (DNA) synthesis that leads to megaloblast formation and megaloblastic and macrocytic anemias.

The role of Folic acid (Vitamin B9) is to:

• Act on megaloblastic bone marrow to produce a normoblastic marrow
• Support nucleoprotein synthesis and maintain normal erythropoiesis
• Serve as a precursor of tetrahydrofolic acid for the biosynthesis of purines and thymidylates of nucleic acids 2

From the Research

Role of Folic Acid (Vitamin B9)

• Folic acid is required for the formation of the neural tube early in pregnancy, around 28 days after conception 3
• It acts as a coenzyme for the transfer of 1 carbon in the biosynthesis of purine, pyrimidine, and amino acids, and is critically important in rapidly proliferating tissues, including fetus and trophoblastic tissue to prevent neural tube defect (NTD) 4
• Maternal folate insufficiency before and during early pregnancy is the most common risk factor for NTDs, and folic acid supplementation has been proven to decrease or minimize specific birth defects 5

Prevention of Neural Tube Defects

• Current guidelines recommend that all women planning or capable of pregnancy take a daily supplement containing 400-800 μg of folic acid to prevent NTDs 3
• Folic acid supplementation is unlikely to mask vitamin B12 deficiency, and investigations are not required prior to initiating folic acid supplementation for women with a risk for primary or recurrent neural tube or other folic acid-sensitive congenital anomalies who are considering a pregnancy 6
• Mandatory folic acid fortification of staple foods is safe, economical, and an effective intervention for primary prevention of NTDs, and has been estimated to avert approximately 1,000 NTD-affected pregnancies annually in the United States 7

Recommendations for Folic Acid Supplementation

• Women should be advised to maintain a healthy folate-rich diet, and folic acid/multivitamin supplementation is needed to achieve the red blood cell folate levels associated with maximal protection against neural tube defect 6
• All women in the reproductive age group should be advised about the benefits of folic acid in a multivitamin supplementation during medical wellness visits, whether or not a pregnancy is contemplated 6
• Women with a high risk for NTDs should be advised to take a daily oral supplement with 4.0 mg folic acid for at least 3 months before conception and until 12 weeks' gestational age 6