Folatenmol/L
Folate status
Also known as: Serum Folate, Vitamin B9
Typical optimal range
8.83–60.8 nmol/L
A typical optimal range for serum folate is around 8.83–60.8 nmol/L, though reference intervals vary between laboratories and should always be interpreted alongside the report issued by your own lab. These figures are indicative — the range printed on your own lab report is the definitive one for your results.
Interpretation of folate results follows NHS and NICE guidance on the investigation of anaemia and nutritional deficiencies, including NICE guidance on anaemia management; the NHS also provides specific advice on folic acid in pregnancy.
What is Folate?
Folate, also known as vitamin B9, is a water-soluble vitamin found naturally in food and in the synthetic form (folic acid) in supplements and fortified foods. It plays a critical role in DNA synthesis and repair, the production of healthy red blood cells, and a chemical process called methylation, which affects everything from gene expression to the metabolism of homocysteine. Measuring serum folate gives a snapshot of your current folate intake and short-term status, making it useful for investigating anaemia, fatigue, or nutritional concerns.
What a high Folate means
A raised serum folate result is most often straightforward and reflects recent high dietary intake or supplement use, but in some contexts it is worth a closer look, particularly to rule out an interaction with vitamin B12 status.
- Supplementation or fortified foods. Taking folic acid supplements — including high-dose pregnancy supplements or multivitamins — is the most common reason for an elevated result. Fortified breakfast cereals and some functional foods can also push levels up noticeably.
- Masking B12 deficiency. High levels of folic acid can correct the blood picture (macrocytic anaemia) caused by vitamin B12 deficiency without addressing the underlying neurological damage, which can then progress undetected. This is why B12 is routinely checked alongside folate.
- Reduced cellular uptake. In rare cases, very high serum folate alongside low red-cell folate or persistent symptoms may suggest the body is not using folate efficiently, sometimes linked to genetic variants such as MTHFR, though this area of evidence is still evolving.
A single high result is rarely concerning on its own; the key clinical question is whether vitamin B12 status is adequate, as the two markers are interpreted together.
What a low Folate means
A low serum folate result can be a meaningful signal worth investigating, particularly if you have symptoms such as unexplained tiredness, breathlessness, or mouth ulcers, as it is associated with macrocytic anaemia and raised homocysteine levels.
- Insufficient dietary intake. Folate is found predominantly in vegetables, pulses, and fortified foods; a diet low in these — whether through restricted eating, food poverty, or ultra-processed food reliance — is the most common reason for low levels in the UK.
- Increased demand or poor absorption. Pregnancy, breastfeeding, rapid growth, chronic alcohol use, inflammatory bowel conditions such as Crohn's disease, and certain medications (including methotrexate and some anticonvulsants) can all deplete folate or impair its absorption from the gut.
Red-cell folate, which reflects longer-term status, is sometimes measured alongside serum folate to build a fuller picture; your GP can advise which test is most relevant for your situation.
Should I be worried?
A single folate result outside the reference range is rarely cause for alarm on its own, but it is worth discussing with your GP, especially if you have symptoms or are planning a pregnancy. Clinicians typically look at folate alongside vitamin B12 and a full blood count, since these markers interact and anaemia can have several overlapping causes. If your result is low, your GP may ask about your diet, any medications you take, and gut health; if it is high, they will want to ensure your B12 levels are adequate. Repeat testing after a dietary change or supplement course is common practice, and most folate issues are straightforward to address once the cause is identified.
What actually helps
The most effective ways to support healthy folate levels are through diet and, where clinically appropriate, supplementation.
- Eat more folate-rich vegetables. Dark leafy greens such as spinach, kale, and spring greens are among the richest natural sources of folate. Cooking lightly rather than boiling for long periods helps preserve the vitamin, which is heat-sensitive.
- Include legumes regularly. Lentils, chickpeas, kidney beans, and other pulses are excellent, affordable sources of dietary folate and fit well into everyday UK cooking. Tinned varieties are just as nutritious as dried.
- Take folic acid if planning pregnancy. NHS guidance recommends 400 micrograms of folic acid daily from before conception until 12 weeks of pregnancy to reduce the risk of neural tube defects; a higher dose (5 mg) is advised for those with certain risk factors, on prescription from a GP.
- Consider methylfolate if MTHFR variant is confirmed. A small proportion of people carry variants in the MTHFR gene that reduce the conversion of folic acid to its active form; in confirmed cases, some clinicians suggest methylfolate (5-MTHF) supplements, though evidence for routine use in the general population remains limited and this should be discussed with a GP.
Good supporting evidence links the following foods to healthier folate status.
Dark leafy greens (spinach, kale, spring greens)
Among the richest natural dietary sources of folate; widely available and versatile in UK cooking.
Legumes (lentils, chickpeas, kidney beans)
High in folate and fibre; tinned versions are convenient and nutritionally equivalent to dried.
Fortified breakfast cereals
Many UK breakfast cereals are fortified with folic acid, making them a practical everyday source, particularly for people with limited vegetable intake.
Asparagus
A well-recognised folate source, especially in season; also provides other B vitamins.
Edamame and broad beans
Both are notably high in folate and work well as snacks or added to salads and stews.
Oranges and orange juice
A useful folate source in the UK diet; fresh or not-from-concentrate juice provides a meaningful contribution alongside other nutrients.
Track your own Folate
Upload a lab PDF and Better Days trends Folate over time, flags it when it drifts, and suggests foods that help.
More in Vitamins/Minerals
Sources & further reading
These are reputable UK health resources for further reading. This page is written to be consistent with their guidance but is not a substitute for them.
For information only — not medical advice, and not individually reviewed by a clinician. Reference ranges vary by lab and individual. Discuss any results with a qualified clinician before making changes.