What does a low folate level mean?

A low folate (vitamin B9) means your body lacks enough of this vitamin to make healthy red blood cells and DNA. It can cause a macrocytic anaemia, where red blood cells are larger than normal, leading to fatigue and weakness. Common causes include a diet low in leafy greens and legumes, increased needs in pregnancy, malabsorption conditions like coeliac disease, excess alcohol, and certain medications. Folate is usually checked together with vitamin B12 because their deficiencies look similar.

Why is folate tested with vitamin B12?

Both folate and B12 are needed to make red blood cells, and a deficiency of either causes the same large-cell (macrocytic) anaemia. Critically, treating someone with folate when they are actually B12-deficient can correct the blood count while allowing B12-related nerve damage to progress unnoticed. To avoid this, doctors check B12 alongside folate and treat any B12 deficiency appropriately before or together with folate.

How much folic acid should I take in pregnancy?

Most guidelines recommend taking a folic acid supplement when trying to conceive and through the first trimester to reduce the risk of neural tube defects such as spina bifida. A standard daily dose is commonly advised for most women, with a higher dose for those at increased risk (for example, a previous affected pregnancy, diabetes, or certain medications). Your doctor will confirm the right dose for your situation — this is one of the best-evidenced uses of a supplement.

Can I get enough folate from food?

Many people can, by eating folate-rich foods such as leafy green vegetables, legumes, citrus fruits, and fortified grains. In some countries, flour and grains are fortified with folic acid, which helps. However, requirements rise in pregnancy, and absorption can be reduced by gut conditions or alcohol, so supplements are recommended in these situations. If a blood test shows deficiency, your doctor will advise on diet and whether a supplement is needed.

Understanding Your Folate (Vitamin B9) Test Results

Quick answer: Folate (vitamin B9) is essential for making red blood cells and DNA, and is especially important before and during pregnancy to prevent neural tube defects. A low folate level can cause a type of anaemia (large red blood cells). Folate is often tested together with vitamin B12, because the two work closely and their deficiencies overlap — and treating folate deficiency without checking B12 first can be a problem.

Folate rarely makes headlines, but it sits behind two important things: healthy red blood cells and healthy early pregnancy. Its result is best understood alongside vitamin B12, because the two are intertwined and getting the order of treatment wrong can mask a serious B12 problem.

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Folate Reference Range

Result	Interpretation
Serum folate above ~7 nmol/L (3 ng/mL)	Generally adequate (varies by lab)
Below range	Low — possible folate deficiency
Borderline	May need a red-cell folate or repeat test

Serum folate reflects recent intake and can fluctuate; red-cell folate reflects longer-term stores. Ranges vary by lab.

Why Folate and B12 Are Tested Together

Folate and B12 both make healthy red blood cells, and deficiency of either causes the same picture — large red cells (macrocytic anaemia). Crucially, giving folate to someone who is actually B12-deficient can improve the blood count while letting B12-related nerve damage progress silently. That is why doctors check B12 alongside folate before treating.

Helpful for this appointment

folate supplement — for confirmed deficiency or pregnancy planning (confirm with your doctor)
appointment notebook — to record results and symptoms across visits

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What Causes Low Folate

Low dietary intake (few leafy greens, legumes, fortified foods)
Increased need: pregnancy, breastfeeding
Malabsorption: coeliac disease, inflammatory bowel disease
Excess alcohol
Some medications (methotrexate, certain anti-epileptics)

Folate in Pregnancy

Adequate folate before conception and in early pregnancy substantially reduces the risk of neural tube defects (such as spina bifida). Most guidelines recommend a folic acid supplement when trying to conceive and through the first trimester — higher doses for those at increased risk. This is one of the clearest, best-evidenced uses of a supplement in medicine.

Questions to Ask Your Doctor

Is my folate low, and has my B12 been checked at the same time?
Could diet, alcohol, or a gut condition be the cause?
If I am pregnant or planning, what folic acid dose is right for me?
Do I need a supplement, and for how long?
Should we look for an underlying absorption problem?

Regional Notes

Singapore: Folate and B12 are commonly tested together when anaemia or fatigue is investigated; folic acid is widely available. Preconception folic acid is routinely advised.

Australia: Bread-making flour is folic-acid fortified. GPs test folate with B12 for macrocytic anaemia; preconception supplementation is standard advice.

United States: Enriched grains are folic-acid fortified. Folate is tested with B12; the CDC recommends preconception folic acid for all women who could become pregnant.

KEY SOURCES

RELATED GUIDES

📊 See the full chart: compare this with typical adult ranges for common tests in our Blood Test Normal Ranges reference chart.

Medical Disclaimer: This guide is for informational and preparation purposes only. It does not constitute medical advice, diagnosis, or treatment. Always consult a qualified medical professional for guidance specific to your situation.