From the Guidelines
The recommended daily dose of vitamin B9 (folate) for most adults is 400 micrograms (mcg) per day, as supported by the USPSTF's 2017 recommendation 1.
Key Considerations
- Pregnant women should take 600 mcg daily, while breastfeeding women need 500 mcg daily.
- For those with folate deficiency, higher therapeutic doses of 1,000 mcg (1 mg) may be prescribed, as recommended by the Society of Obstetricians and Gynaecologists of Canada for women with a personal history of neural tube defects or other birth defects 1.
- When purchasing B9 supplements, look for methylfolate (5-MTHF) rather than folic acid, as it's more readily usable by the body, especially for people with MTHFR gene variants who have difficulty converting folic acid.
- Take B9 supplements with food to enhance absorption, and consider a B-complex supplement since B vitamins work synergistically.
Importance of Folate
- Folate is essential for DNA synthesis, cell division, and preventing neural tube defects in developing fetuses.
- It also supports red blood cell formation and helps maintain normal homocysteine levels, which is important for cardiovascular health.
- If you have specific health conditions or take medications, consult with a healthcare provider before starting supplementation, as excessive folate consumption can mask vitamin B12 deficiency-related neurological symptoms 1.
From the Research
B9 Dietary Supplement Dose
- The ideal dose of B9 (folate) supplement is not explicitly stated in the provided studies, but we can look at the doses used in various studies to understand the range of effective doses.
- A study from 2018 2 used doses of 400 µg/day and 800 µg/day of folate to achieve desirable red blood cell folate concentrations in non-pregnant women.
- Another study from 1993 3 used a high dose of 400 mg/day of folic acid to treat homocystinuria due to 5,10-methylenetetrahydrofolate reductase deficiency.
- It's worth noting that the dose of folate required to achieve desirable levels can vary depending on individual factors, such as the presence of deficiencies or certain medical conditions.
- For example, a study from 2024 4 found that patients with rheumatoid arthritis treated with methotrexate and folic acid had high plasma homocysteine levels, suggesting that higher doses of folate may be needed in these patients.
- A study from 2010 5 found that elevated depressive symptoms were inversely associated with folate status, particularly among women, suggesting that adequate folate levels may be important for mental health.
Key Findings
- High doses of folic acid (400 mg/day) can be effective in reducing homocysteine levels in patients with homocystinuria due to 5,10-methylenetetrahydrofolate reductase deficiency 3.
- Doses of 400 µg/day and 800 µg/day of folate can be effective in achieving desirable red blood cell folate concentrations in non-pregnant women 2.
- Patients with rheumatoid arthritis treated with methotrexate and folic acid may require higher doses of folate to achieve desirable homocysteine levels 4.
- Adequate folate levels may be important for mental health, particularly among women 5.