Low folate: what it means and what to do

Low folate means little has come in recently, or your body is using or losing more. The most common causes are few vegetables and legumes, alcohol, coeliac disease and some medicines. It often corrects well, but B12 should be checked first.

What low folate means

Folate helps make red blood cells and build new cells. If too little comes in, blood levels fall within a few weeks.

How low it is matters. Just below your report’s limit, it often reflects only a few days of low intake. Below 3 ng/mL there is usually a real shortage, and the risk of anaemia rises.

Low folate on its own is not a diagnosis. It tells you to look at your blood count and vitamin B12.

What causes low folate

There is often more than one. The most common come first.

• Too little folate in your diet: Few leafy greens, few legumes and little fruit. This is the most common cause.
• Alcohol: People who drink a lot absorb less and lose more in their urine.
• Reduced absorption: For example with coeliac disease or other bowel conditions.
• A higher need: In pregnancy and breastfeeding, or with conditions that destroy more red blood cells than usual.
• Some medicines: Methotrexate, some anti-epileptics and some antibiotics, among others. Do not stop them on your own: talk to your doctor.

Symptoms of low folate

Often there are none. If the shortage lasts and causes anaemia, you may notice:

• Tiredness and shortness of breath with little effort
• Paleness
• A red, sore tongue, or frequent mouth ulcers
• Trouble concentrating

Tingling in your hands and feet points more to a B12 shortage. That is why your doctor always checks B12 too.

Low folate and pregnancy

In early pregnancy folate helps the baby’s nervous system form properly. That is why folic acid is advised for every woman trying for a baby or not ruling one out, from at least one month before conception until the third month.

If your folate is low and you are thinking about a pregnancy, talk to your doctor or gynaecologist soon. They will tell you which dose to take and from when.

Which tests to read alongside it

These tests help show how much it matters and where it comes from.

What your result means

The lower end of the scale, in ng/mL.

• Below 3: Very low. Usually a real folate shortage. Below this level the risk of anaemia rises sharply. Talk to your doctor: they usually check B12 and a full blood count before any treatment.
• 3 to 3.9: Low. Below the limits on many lab reports, but in a grey zone. It often reflects little folate in recent days. Show it to your doctor, with B12 and a blood count. Often a change in what you eat is enough.
• 3.9 to 26.8: Normal. You are getting enough folate, at least in the days before the test. Nothing to do.

How to raise your folate

It depends on the cause. Where to start:

• First, with your doctor, check B12 and a blood count: if B12 is short too, it is treated first.
• What to eat: leafy greens such as spinach, broccoli and lettuce, legumes, citrus fruit and nuts. Long cooking destroys some of it: mix raw and cooked.
• If you drink a lot of alcohol, cutting down helps folate recover.
• If your doctor suggests a supplement, ask which one and for how long.

Do not take high-dose folic acid without asking your doctor: it can correct the anaemia and hide a B12 shortage that keeps damaging your nerves.

Low folate: when to worry

Talk to your doctor if:

• Your folate is below your report’s limit, especially below 3 ng/mL.
• Your B12 is low too, or your MCV is high.
• You have tiredness that does not go away, shortness of breath or paleness.
• You have tingling or numbness in your hands and feet.
• You are planning a pregnancy or are pregnant: talk to your doctor or gynaecologist soon.
• You have chest pain, fainting or find it very hard to breathe: call 112 or go to the emergency department.

Frequently asked questions

What are the symptoms of low folate? Often none. If the shortage causes anaemia, you may have tiredness, shortness of breath, paleness, a red tongue or mouth ulcers.

What should I eat for low folate? Leafy greens, broccoli, legumes, citrus fruit and nuts. Mix raw and cooked, because long cooking destroys some of it.

Low folate in pregnancy: what should I do? Talk to your gynaecologist or doctor straight away. Folate matters more in pregnancy, and they decide the right dose.

How long does folate take to come back up? In the blood it rises quickly, within days on the right diet or treatment. Correcting anaemia takes longer. Your doctor decides when to recheck.

Low folate and low B12 together: what does it mean? It is common, for example with a poor diet or absorption problems. Your doctor usually treats B12 first and then adds folate.

Does low folate make you gain or lose weight? There is no direct link with weight. If you are losing weight without trying, talk to your doctor: the cause needs to be looked for separately.

Sources

• Devalia and colleagues, guidelines for the diagnosis and treatment of cobalamin and folate disorders. British Journal of Haematology, 2014. PMID 24942828
• Cordero and colleagues, optimal serum and red blood cell folate concentrations in women of reproductive age for prevention of neural tube defects: World Health Organization guidelines. MMWR, 2015. PMID 25905896
• Istituto Superiore di Sanità, EpiCentro: folic acid and folate, the recommendation of the Italian folic acid promotion network. ISS, Network italiano promozione acido folico
• Liverpool University Hospitals, serum folate laboratory test sheet: reference interval of the method in use. Liverpool University Hospitals NHS, serum folate