Folate
| Clinical | Optimal | |
|---|---|---|
| Male | 3.9 - 26.8 nmol/L | >20 nmol/L |
| Female | 3.9 - 26.8 nmol/L | >20 nmol/L |
What is Folate?
Folate is the natural form of vitamin B9, found in foods like leafy green vegetables, legumes, and liver. Its synthetic counterpart, folic acid, is used in supplements and fortified foods. Your blood test measures serum folate — the amount circulating in your blood at the time of testing.
Folate plays a central role in one-carbon metabolism, a biochemical pathway essential for DNA synthesis and repair, amino acid metabolism, and the formation of red and white blood cells. It works closely with vitamin B12, and the two are often tested together.
Without adequate folate, your body cannot produce new cells efficiently. This is why folate is particularly important during periods of rapid cell division, such as pregnancy, childhood growth, and tissue repair.
Why Folate Matters for Your Health
Folate is essential for keeping homocysteine levels in check. Homocysteine is an amino acid that, when elevated, is associated with increased cardiovascular risk, cognitive decline, and accelerated ageing. Adequate folate (along with B12 and B6) keeps homocysteine within a healthy range.
For brain health and mood, folate is involved in the production of neurotransmitters including serotonin, dopamine, and noradrenaline. Low folate levels have been linked to depression and impaired cognitive function.
From a longevity perspective, maintaining optimal folate supports DNA repair mechanisms that protect against mutations and cellular ageing. It is one of the most important B vitamins for long-term health maintenance.
Folate& Your Wearable Data
Folate (vitamin B9) is essential for DNA synthesis, red blood cell production, and cellular repair. It works closely with vitamin B12 in these processes. Wearable data can reveal patterns associated with folate deficiency: anaemia from low folate reduces oxygen-carrying capacity, which manifests as elevated heart rates during exercise, declining VO2 max, and increased fatigue visible in your activity and recovery data.
Physical activity increases folate turnover. Athletes and highly active individuals tracked by wearables have higher folate requirements due to increased red blood cell production and tissue repair demands. If your wearable shows high training volumes alongside declining performance and elevated exercise heart rates, folate deficiency should be considered alongside iron status.
Folate status influences homocysteine levels, an independent cardiovascular risk marker. Your wearable's cardiovascular metrics — resting heart rate trends, HRV, and exercise recovery — provide complementary data for assessing overall cardiovascular health alongside folate and homocysteine blood levels.
What High Folate May Suggest
High serum folate is almost always the result of supplementation or a diet exceptionally rich in folate-containing foods. It is not harmful in itself and is generally not a clinical concern.
There has been some theoretical discussion about very high folate levels potentially masking vitamin B12 deficiency, but this is mainly relevant in the context of folic acid supplementation without concurrent B12 monitoring. If you supplement with folic acid, ensuring your B12 status is also healthy is sensible practice.
In rare instances, very high folate in someone not supplementing could prompt a GP to check for a condition called small intestinal bacterial overgrowth (SIBO), where gut bacteria produce excess folate.
What Low Folate May Suggest
Low folate suggests your body may not have enough vitamin B9 to support optimal DNA synthesis, cell division, and homocysteine metabolism. Results below 7 nmol/L indicate deficiency.
Common causes include a diet low in green vegetables and legumes, excessive alcohol consumption (which impairs folate absorption and increases excretion), coeliac disease or other malabsorption conditions, certain medications (methotrexate, some anti-epileptic drugs), and pregnancy (which dramatically increases folate requirements).
Symptoms of deficiency include fatigue, weakness, mouth ulcers, a sore tongue, poor concentration, and in severe cases, megaloblastic anaemia (where red blood cells are abnormally large and inefficient). Low folate during early pregnancy significantly increases the risk of neural tube defects.
How to Optimise Your Folate
Food
Eat plenty of dark leafy greens (spinach, kale, spring greens, broccoli), legumes (lentils, chickpeas, black beans), asparagus, beetroot, and liver. Folate is sensitive to heat, so lightly steaming vegetables rather than boiling preserves more of the vitamin. Brussels sprouts, peas, and avocado are also excellent sources. Aim for at least five portions of folate-rich vegetables daily.
Lifestyle
Reduce alcohol consumption, as even moderate drinking impairs folate absorption and increases urinary losses. Address any digestive issues that might affect nutrient absorption. Eat a varied diet rich in whole foods rather than relying on processed options. If you take medications known to deplete folate, discuss monitoring with your GP.
Supplements
Methylfolate (5-MTHF) is the most bioavailable supplemental form and is preferred over synthetic folic acid, especially for individuals with MTHFR gene variants that impair folic acid conversion. A typical dose is 400–800 mcg daily. Always ensure adequate B12 intake alongside folate supplementation, as the two vitamins work synergistically.
When to Speak to Your GP
See your GP if serum folate is below 7 nmol/L, particularly if you have symptoms of anaemia (fatigue, pallor, breathlessness). Seek advice if you are planning a pregnancy, as preconception folate supplementation is essential. Also consult your GP if low folate persists despite dietary improvements, as this may indicate an absorption problem requiring investigation.
References
- NHS. Vitamin B12 or folate deficiency anaemia — Overview. Updated 2024. nhs.uk
- NICE. Anaemia — B12 and folate deficiency. Clinical Knowledge Summaries. cks.nice.org.uk
- WHO. Serum and red blood cell folate concentrations for assessing folate status. Geneva: WHO; 2015. who.int
- BMJ. Devalia V, et al. Guidelines for the diagnosis and treatment of cobalamin and folate disorders. Br J Haematol. 2014;166(4):496-513. pubmed.ncbi.nlm.nih.gov
Medical Disclaimer— This content is for general educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Omniwo Ltd is a wellness information service and is not a medical device, clinical laboratory, or regulated healthcare provider under MHRA guidelines. The “optimal ranges” presented on this page are based on published clinical guidelines (WHO, NICE, NHS) and peer-reviewed research; they represent functional wellness targets and may differ from standard laboratory reference ranges. Individual results should always be interpreted by a qualified healthcare professional (such as your GP) who understands your full medical history. Do not start, stop, or change any medication or supplement based solely on this information. If you are experiencing symptoms, seek medical attention promptly.