# Vitamin B9 (Folate) in Plasma

> Folate, also known as Vitamin B9 or folic acid in its synthetic form, is vital for DNA synthesis, repair, methylation, and red blood cell production. It's 

*Source: [https://www.health3.app/biomarkers/vitaminb9_plasma](https://www.health3.app/biomarkers/vitaminb9_plasma)*

### On This Page

- What it measures
- Measurement units
- Reference ranges
- Health impact
- Related biomarkers
- Scientific references

## What is Vitamin B9 (Folate) in Plasma?

Folate, also known as Vitamin B9 or folic acid in its synthetic form, is vital for DNA synthesis, repair, methylation, and red blood cell production. It's crucial for brain function and mental health, and its importance is heightened during pregnancy for fetal development, significantly reducing the risk of neural tube defects. Folate deficiency can lead to megaloblastic anemia, characterized by larger and underdeveloped red blood cells, and symptoms like fatigue and weakness. In pregnant women, low folate levels can cause birth defects, including neural tube defects.

Folate interacts with other nutrients affecting its absorption and utilization. **Vitamin B12 deficiency can lead to a functional folate deficiency**, as B12 is necessary to recycle folate in the body. Conversely, **high folate levels can mask B12 deficiency symptoms. Zinc deficiency can impair folate utilization, while chronic alcohol consumption can reduce folate absorption and increase its excretion**. **Certain medications, like antiepileptic drugs, can interfere with folate absorption and metabolism**.

Folate toxicity is rare due to its water-soluble nature, with excess typically excreted in urine. However, excessive folic acid intake can mask vitamin B12 deficiency symptoms without preventing neurological damage caused by the deficiency.

To **maintain healthy Vitamin B9 (folate) levels**:

- Consume a varied diet rich in folate-containing foods, such as leafy green vegetables, citrus fruits, legumes, whole grains, and fortified foods.
- If you have a genetic variant affecting folate metabolism (such as MTHFR), work with your healthcare provider to determine the appropriate form and dosage of folate supplementation.
- Be mindful of potential interactions with medications, such as antiepileptic drugs, that can interfere with folate absorption and metabolism. Discuss any concerns with your healthcare provider.
- Ensure adequate intake of other nutrients that influence folate utilization, such as **vitamin B12** and **zinc**, through a balanced diet or supplementation if necessary.

## Measurement Units

Vitamin B9 (Folate) in Plasma can be measured in: ng/100mL, ng/dL, ng/L, ng/mL, ng%, nmol/L, pmol/L, µg/L

## Reference Ranges by Age and Gender

Reference ranges represent typical values for healthy individuals. Your healthcare provider must interpret your specific results.

| Age Range | Gender | Unit | Optimal | Normal | Source |
| --- | --- | --- | --- | --- | --- |
| All ages | All genders | ng/mL | - | 2 - 20 | Dunning, 2015 |
| 19 - 79 | All genders | ng/mL | - | 9.5 - 39 | Rifai, 2023 |

## Related Biomarkers

- [**Vitamin B12 (Cobalamin)**](https://www.health3.app/biomarkers/vitaminb12)

 Folate and vitamin B12 have a synergistic relationship, particularly in DNA synthesis and repair, and the metabolism of homocysteine. They depend on each other to and deficiency in either vitamin can lead to megaloblastic anemia and elevated homocysteine levels, increasing the risk of cardiovascular disease.[Scott, 1999][Stabler, 2013]
- [**Holotranscobalamin**](https://www.health3.app/biomarkers/holotransc)

 Folate and vitamin B12 have a synergistic relationship, particularly in DNA synthesis and repair, and the metabolism of homocysteine. They depend on each other to and deficiency in either vitamin can lead to megaloblastic anemia and elevated homocysteine levels, increasing the risk of cardiovascular disease.[Scott, 1999][Stabler, 2013]

## Academic References

1. An H, Xue Q, and Zhang J. The association between serum total folic acid concentration and severe difficulty falling asleep in US adults: NHANES008 (2005). *Front Neurol*. [DOI: 10.3389/fneur.2023.1225403](https://doi.org/10.3389/fneur.2023.1225403)
2. Ames B. N., Courtemanche C, Elson-Schwab I, Kerry N, and Mashiyama ST. Folate deficiency inhibits the proliferation of primary human CD8+ T lymphocytes in vitro (2004). *J Immunol*. [DOI: 10.4049/jimmunol.173.5.3186](https://doi.org/10.4049/jimmunol.173.5.3186)
3. Selhub J. Homocysteine metabolism (1999). *Annu Rev Nutr.*. [DOI: 10.1146/annurev.nutr.19.1.217](https://doi.org/10.1146/annurev.nutr.19.1.217)
4. Rifai N.. Tietz Textbook of Laboratory Medicine (2023). *Elsevier*.
5. Gregory JF 3rd. Case study: folate bioavailability (2001). *J Nutr*. [DOI: 10.1093/jn/131.4.1376S](https://doi.org/10.1093/jn/131.4.1376S)
6. Scott J.M.. Folate and vitamin B12 (1999). *Proceedings of the Nutrition Society*. [DOI: 10.1017/s0029665199000580](https://doi.org/10.1017/s0029665199000580)
7. Armstrong NC, Bradbury I, McConville C, McNulty H, Stewart-Knox B, and Williams E. Folate status and mood: is there a relationship? (2008). *Public Health Nutrition*. [DOI: 10.1017/S1368980007000031](https://doi.org/10.1017/S1368980007000031)
8. Dunning MB and Fischbach F. Manual of Laboratory and Diagnostic Tests (2015). *Manual of Laboratory and Diagnostic Tests*.
9. De Looze C., O’Connor D.M.A., and Scarlett S.. Low folate predicts accelerated cognitive decline: 8-year follow-up of 3140 older adults in Ireland (2022). *Eur J Clin Nutr*. [DOI: 10.1038/s41430-021-01057-3](https://doi.org/10.1038/s41430-021-01057-3)
10. Nygård O., Refsum H., Ueland P. M., and Vollset S. E.. Homocysteine and cardiovascular disease (1998). *Annual Review of Medicine*. [DOI: 10.1146/annurev.med.49.1.31](https://doi.org/10.1146/annurev.med.49.1.31)
11. Ghishan FK, Greene HL, Murrell JE, Said HM, and Wilson PC. Intestinal transport of zinc and folic acid: a mutual inhibitory effect (1986). *Am J Clin Nutr*. [DOI: 10.1093/ajcn/43.2.258](https://doi.org/10.1093/ajcn/43.2.258)
12. Emmerson Joshua, Jadavji Nafisa., and Murray Lauren. The role of folates in neruological functions (2017). *Folic Acid: Sources, Health Effects, and Role in Disease*. [View Source](https://www.researchgate.net/publication/317905049_The_role_of_folates_in_neruological_functions)
13. Dhur A, Galan P, and Hercberg S. Folate status and the immune system (1991). *Prog Food Nutr Sci*.
14. Stabler S.P.. Vitamin B12 deficiency (2013). *New England Journal of Medicine*. [DOI: 10.1056/NEJMcp1113996](https://doi.org/10.1056/NEJMcp1113996)
15. Morris MS. The role of B vitamins in preventing and treating cognitive impairment and decline (2012). *Adv Nutr*. [DOI: 10.3945/an.112.002535](https://doi.org/10.3945/an.112.002535)
16. Beydoun HA, Beydoun MA, Canas JA, Gamaldo AA, McNeely JM, Shah MT, and Zonderman AB. Serum nutritional biomarkers and their associations with sleep among US adults in recent national surveys (2014). *PLoS One*. [DOI: 10.1371/journal.pone.0103490](https://doi.org/10.1371/journal.pone.0103490)
17. De Looze C., O’Connor D.M.A., and Scarlett S.. Low folate predicts accelerated cognitive decline: 8-year follow-up of 3140 older adults in Ireland (2022). *Eur J Clin Nutr*. [DOI: 10.1038/s41430-021-01057-3](https://doi.org/10.1038/s41430-021-01057-3)
18. Gershoff SN, Meydani SN, Morrow FD, Ribaya-Mercado JD, Russell RM, and Sahyoun N. Vitamin B-6 deficiency impairs interleukin 2 production and lymphocyte proliferation in elderly adults (1991). *Am J Clin Nutr*. [DOI: 10.1093/ajcn/53.5.1275](https://doi.org/10.1093/ajcn/53.5.1275)
19. Cutler RG, Evans M, Haughey N, Kruman II, Kruman Y, Kumaravel TS, Lee J, Lohani A, Mattson MP, and Pedersen WA. Folic acid deficiency and homocysteine impair DNA repair in hippocampal neurons and sensitize them to amyloid toxicity in experimental models of Alzheimer's disease (2002). *J Neurosci*. [DOI: 10.1523/JNEUROSCI.22-05-01752.2002](https://doi.org/10.1523/JNEUROSCI.22-05-01752.2002)
20. Arnold MJ, Fodor G, Genest J Jr., Held C, Lonn E, McQueen MJ, Micks M, Pogue J, Probstfield J, Sheridan P, and Yusuf S. Homocysteine lowering with folic acid and B vitamins in vascular disease (2006). *N Engl J Med*. [DOI: 10.1056/NEJMoa060900](https://doi.org/10.1056/NEJMoa060900)
21. Blache D, Coudray C, Faure P, Favier A, Favier M, and Roussel AM. Zinc deficiency and dietary folate metabolism in pregnant rats (1993). *J Trace Elem Electrolytes Health Dis*. [View Source](https://pubmed.ncbi.nlm.nih.gov/8400843/)
22. Enomoto S, Hama Y, Hamano T, Hayashi K, Ikawa M, Ito T, Kimura H, Kimura Y, Kuriyama M, Matsunaga A, Nagata M, Nakamoto Y, Shirafuji N, Ueno A, and Yamamura O. Influences of Folate Supplementation on Homocysteine and Cognition in Patients with Folate Deficiency and Cognitive Impairment (2020). *Nutrients*. [DOI: 10.3390/nu12103138](https://doi.org/10.3390/nu12103138)
23. Cornett EM, Fuller MC, Jeha GM, Kaye AD, Kevil CG, Lerner ZI, Pham AD, Sibley GT, Urits I, and Viswanath O. Folic Acid Supplementation in Patients with Elevated Homocysteine Levels (2020). *Adv Ther*. [DOI: 10.1007/s12325-020-01474-z](https://doi.org/10.1007/s12325-020-01474-z)
24. Durga J, Jolles J, Katan MB, Kok FJ, Schouten EG, van Boxtel MP, and Verhoef P. Effect of 3-year folic acid supplementation on cognitive function in older adults in the FACIT trial: a randomised double blind controlled trial (2007). *Lancet*. [DOI: 10.1016/S0140-6736(07)60109-3](https://doi.org/10.1016/S0140-6736(07)60109-3)

### ⚠️ Important Medical Information

This reference page is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Reference ranges vary between laboratories. Always review your lab results with a qualified healthcare provider.