From the Guidelines
All women of childbearing age should take 400 micrograms of folic acid daily, ideally starting at least one month before conception and continuing through the first trimester to prevent neural tube defects in the developing fetus. This recommendation is based on the evidence from the American College of Medical Genetics, which suggests that all women capable of becoming pregnant should strive for an intake of 400 micrograms of folic acid daily, in the form of a supplement, multivitamin, consumption of fortified foods, or a combination of the above 1.
The U.S. Preventive Services Task Force also recommends that all women planning or capable of pregnancy take a daily supplement containing 0.4 to 0.8 mg (400 to 800 μg) of folic acid, with a grade A recommendation 1.
Some key points to consider:
- Women who have had a previous neural tube defect-affected pregnancy, who are themselves affected, have a first- or second-degree relative with a neural tube defect, or who have diabetes mellitus type 1 may be advised to take 4 mg of folic acid commencing 3 months before conception and continuing throughout the first trimester 1.
- Folate is essential for DNA synthesis, cell division, and proper neural development, and the body cannot produce folate, making dietary intake or supplementation necessary.
- While many foods contain natural folate (leafy greens, legumes, fruits), the synthetic form folic acid in supplements has higher bioavailability.
- Most multivitamins contain adequate folate, but specific folic acid supplements are also available over-the-counter.
- People with certain medical conditions like malabsorption disorders, alcoholism, or those taking medications that interfere with folate metabolism (such as methotrexate, phenytoin, or sulfasalazine) may require higher supplementation doses.
It's worth noting that the evidence from the studies 1 published in 1992 is outdated and has been superseded by more recent guidelines and recommendations. The most recent and highest quality study, published in 2011, provides the most up-to-date guidance on folate supplementation 1.
From the FDA Drug Label
The usual therapeutic dosage in adults and children (regardless of age) is up to 1 mg daily. Daily doses greater than 1 mg do not enhance the hematologic effect, and most of the excess is excreted unchanged in the urine. When clinical symptoms have subsided and the blood picture has become normal, a daily maintenance level should be used, i.e., 0.1 mg for infants and up to 0.3 mg for children under 4 years of age, 0.4 mg for adults and children 4 or more years of age, and 0.8 mg for pregnant and lactating women, but never less than 0. 1 mg/day.
The guidelines for folate supplementation in humans are as follows:
- Therapeutic dosage: up to 1 mg daily for adults and children
- Maintenance level:
- 0.1 mg for infants
- up to 0.3 mg for children under 4 years of age
- 0.4 mg for adults and children 4 or more years of age
- 0.8 mg for pregnant and lactating women
- Minimum daily dose: 0.1 mg/day 2
- Special considerations:
- Patients with alcoholism, hemolytic anemia, anticonvulsant therapy, or chronic infection may require increased maintenance levels
- Pregnant and lactating women have increased folate requirements 2
From the Research
Guidelines for Folate Supplementation
The guidelines for folate supplementation in humans, particularly in pregnant women, are based on the importance of folate in preventing neural tube defects and other congenital malformations.
- Folate deficiency in pregnancy is related to neural tube defects, other neurological disorders, preterm delivery, and low birth weight 3.
- Women of reproductive age should supplement with 0.4-1.0 mg of folic acid daily as part of their multivitamins, in addition to fortification of dietary staples with folic acid 4.
- Certain groups of women, such as those who have had previous pregnancies with neural tube defects, those who did not plan their pregnancy, and women with low intake or impaired adherence to daily folic acid supplementation, may benefit from higher daily doses of folic acid 4.
Folate Supplementation Recommendations
The optimal dosage of folic acid for pregnant women and those planning pregnancy is a topic of ongoing research.
- A study published in 2016 recommended that women of reproductive age supplement with 0.4-1.0 mg of folic acid daily 4.
- Another study published in 2017 suggested that high-dose folic acid supplementation (5 mg/day) may be necessary for certain groups of women, such as those with a history of neural tube defects or those with impaired adherence to daily folic acid supplementation 5.
- However, high-dose folic acid supplementation has also been shown to increase maternal serum folate concentrations, but not RBC folate concentrations, suggesting tissue saturation 6.
Interaction between Folate and Vitamin B12
The interaction between excess folate and low vitamin B12 status is a concern, particularly in older adults and pregnant women.
- An imbalance of high folate status and low vitamin B12 status has been associated with negative health outcomes, including diabetes and insulin resistance in offspring 7.
- Pregnant women are exposed to folic acid at varying doses, and vitamin B12 status can remain low despite adequate intake due to age-related decline in vitamin B12 absorption 7.
- It is essential to consider the potential risks and benefits of folate supplementation, particularly in relation to vitamin B12 status, to ensure optimal health outcomes for pregnant women and their offspring.