Folate

What Is Folate?

Folate is a B vitamin (B9) that your body uses to make new cells — particularly red blood cells and DNA. You might hear "folate" and "folic acid" used interchangeably, but there is a small difference: folate is the natural form found in foods like leafy greens and beans, while folic acid is the synthetic version used in supplements and fortified foods. Your body needs one or the other every single day because it cannot store large amounts for very long.

Folate is especially well known for its critical role during pregnancy, where it helps the baby's brain and spinal cord develop properly. But it is important for everyone, not just expectant mothers — your body relies on it to keep your blood healthy and your cells dividing normally.

What Does It Measure?

A folate blood test measures how much folate is circulating in your bloodstream right now. This is sometimes called serum folate. It reflects your recent dietary intake over the past few days to weeks.

In some cases, your doctor might order a red blood cell (RBC) folate test instead, which measures how much folate is stored inside your red blood cells. This gives a longer-term picture of your folate status over the past 2 to 3 months — similar to how hemoglobin A1c reflects long-term blood sugar. Together, these tests help your doctor understand whether you are getting enough folate consistently.

Normal Ranges

| Group | Range | Unit | |---|---|---| | Adults (serum folate) | 2.7 – 17.0 ng/mL | ng/mL | | Deficient (serum folate) | Below 2.7 ng/mL | ng/mL | | Adults (RBC folate) | 140 – 628 ng/mL | ng/mL | | Pregnant individuals | 2.7 – 17.0 ng/mL (serum) | ng/mL | | Children | 2.7 – 17.0 ng/mL | ng/mL |

Note: Some labs report results in nmol/L. To convert ng/mL to nmol/L, multiply by 2.27. For example, 2.7 ng/mL equals roughly 6.1 nmol/L.

What Does a High Level Mean?

High serum folate levels are uncommon and rarely dangerous. Your body is fairly good at getting rid of excess folate through urine since it is a water-soluble vitamin. However, persistently high levels deserve attention in certain situations.

Possible causes of high folate:

• Taking folic acid supplements (the most common and generally harmless cause)
• Eating a diet very rich in fortified foods
• In rare cases, high folate can mask a vitamin B12 deficiency — the blood counts may look normal even though the B12 problem is causing nerve damage behind the scenes

Common symptoms:

• High folate from supplements usually causes no symptoms
• If it is masking a B12 deficiency, you might experience tingling, numbness, or balance problems without the usual blood count abnormalities that would raise a red flag

Recommended next steps:

• If you take high-dose folic acid supplements, mention this to your doctor
• Your doctor may check your B12 level at the same time to make sure a deficiency is not being hidden
• No treatment is usually needed for high folate alone

What Does a Low Level Mean?

Folate deficiency is one of the most common vitamin deficiencies worldwide. Because your body uses folate so quickly — especially during periods of rapid cell growth — your stores can run low within just a few weeks of poor intake.

Possible causes of low folate:

• A diet low in fruits, vegetables, and legumes
• Heavy alcohol use (alcohol interferes with folate absorption and increases how fast your body uses it up)
• Digestive conditions like celiac disease or inflammatory bowel disease
• Certain medications, including methotrexate, some anti-seizure drugs, and sulfasalazine
• Pregnancy, which dramatically increases folate demand
• Hemolytic anemias or other conditions with high cell turnover
• Older age, due to decreased absorption and dietary changes

Common symptoms of low folate:

• Fatigue and weakness
• Pale skin
• Shortness of breath
• Irritability or difficulty concentrating
• A sore, red tongue or mouth ulcers
• Headaches
• Heart palpitations

Recommended next steps:

• Your doctor will likely recommend a folic acid supplement — typical doses for deficiency are 1 mg daily
• A complete blood count (CBC) may be ordered to check for megaloblastic anemia, which is characterized by unusually large red blood cells
• Your B12 level should also be checked, since folate and B12 deficiencies can look identical on a blood count and treating only one while ignoring the other can cause problems
• Recheck your levels after 4 to 8 weeks of supplementation

When Should You Get Tested?

You might want to talk to your doctor about checking your folate level if you:

• Are pregnant, planning to become pregnant, or breastfeeding
• Have symptoms of anemia like fatigue, weakness, or pale skin
• Drink alcohol regularly or heavily
• Have a digestive condition such as celiac disease, Crohn's disease, or ulcerative colitis
• Take medications known to lower folate (methotrexate, phenytoin, sulfasalazine)
• Have a diet that is low in vegetables and legumes
• Have unexplained mouth sores or a sore tongue
• Are being evaluated for elevated homocysteine levels

How to Improve Your Levels

Food sources: Dark leafy greens like spinach, kale, and romaine lettuce are among the best natural sources of folate. Beans, lentils, asparagus, broccoli, avocados, oranges, and Brussels sprouts are also excellent choices. Many breads, cereals, pasta, and rice in the United States are fortified with folic acid by law.

Supplements: Folic acid is widely available and inexpensive. For general health, 400 mcg daily is the standard recommendation. Women who are pregnant or trying to conceive are typically advised to take 400 to 800 mcg daily. Some people with a genetic variation in the MTHFR gene may benefit from a methylfolate supplement, which is the already-active form — ask your doctor if this applies to you.

Limit alcohol: Even moderate alcohol intake can lower your folate levels. Reducing or eliminating alcohol is one of the most effective ways to protect your folate status.

Cook thoughtfully: Folate is sensitive to heat. Eating some of your vegetables raw or lightly steamed (rather than heavily boiled) helps preserve more of this vitamin.

Frequently Asked Questions

Q: Why is folic acid so important before and during pregnancy?

Folate is essential for the proper closure of the neural tube, which forms the baby's brain and spinal cord, during the first 28 days after conception — often before a woman even knows she is pregnant. Getting enough folic acid before and during early pregnancy dramatically reduces the risk of neural tube defects like spina bifida. This is why doctors recommend starting folic acid supplementation at least one month before trying to conceive.

Q: What is the difference between folate and folic acid?

Folate is the natural form found in whole foods. Folic acid is the synthetic form used in supplements and fortified foods. Your body converts folic acid into the active form of folate it needs. For most people, both forms work well, though some individuals with certain genetic variations may process natural folate more efficiently.

Q: Can I take too much folic acid?

The upper limit for adults is generally set at 1,000 mcg (1 mg) of folic acid per day from supplements and fortified foods. Taking more than this is unlikely to cause direct harm, but it can mask a vitamin B12 deficiency by correcting the anemia while the nerve damage from B12 deficiency continues silently. This is why it is important to have your B12 checked if you are taking high doses of folic acid.

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This content is for educational purposes only and is not medical advice. Always consult your healthcare provider about your lab results.