Folic Acid Deficiency: Key symptoms & when to ask your doctor for a test

If you’ve been feeling tired, a little foggy, or just not yourself lately, it might not just be stress or lack of sleep. Sometimes, your body is trying to tell you something more specific—like you're missing an important nutrient. One common but often overlooked issue is folic acid deficiency. Folic acid (also called folate in its natural form) is a type of B vitamin that plays a big role in your health. It helps your body make red blood cells, supports healthy cell growth, and is even involved in making DNA. That’s why it’s especially important during pregnancy and for anyone with ongoing health conditions, a poor diet, or chronic fatigue.

Read on to learn everything you need to know about folic acid deficiency: what causes it, what symptoms to watch for, and when to ask your doctor for a test.

What is folic acid deficiency?

Folic acid is the synthetic version of folate, a B vitamin (B9) found naturally in foods like leafy greens, beans, and citrus fruits. Your body uses it to build and repair DNA, make red blood cells, and support brain health. A folic acid deficiency happens when you don’t have enough folate in your system to meet your body’s needs. This can affect how your cells work, how much energy you have, and even your mental clarity.

Folate is mainly absorbed in the small intestine. If you’re not getting enough from your diet, or if something is blocking absorption, your folate levels can drop over time—sometimes without obvious signs until the deficiency becomes more serious.

What causes folic acid deficiency?

There are a few common reasons someone might develop a folic acid deficiency. These include:

• Poor diet: Not eating enough folate-rich foods like spinach, beans, citrus, and fortified grains
• Alcohol use: Heavy drinking can block folate absorption and increase how much folate your body flushes out
• Digestive disorders: Conditions like celiac disease, IBS, or Crohn’s can interfere with nutrient absorption
• Medications: Some prescription drugs—such as methotrexate, phenytoin, and sulfasalazine—can reduce folate levels
• Pregnancy: Your body needs more folate during pregnancy to support fetal development
• Chronic illnesses: Kidney dialysis or conditions that increase cell turnover (like cancer) can deplete folate
• Aging: Older adults may have lower absorption rates or dietary restrictions that limit folate intake
  

If one or more of these apply to you, it’s worth keeping folate on your radar.

Symptoms of folic acid deficiency

One tricky thing about folic acid deficiency is that it can sneak up on you. At first, symptoms might be subtle or confused with other conditions, especially iron deficiency. The most common low folic acid symptoms to watch for include:

• Fatigue or weakness
• Pale skin
• Mouth sores or a swollen, red tongue
• Irritability or mood swings
• Loss of appetite
• Difficulty concentrating or memory issues
• Shortness of breath
• Symptoms of folic acid deficiency anemia (like dizziness or a rapid heartbeat)
  

These symptoms often develop gradually, so you might just feel “off” for a while without knowing why. If that sounds familiar, you might be due for a check-up.

When should you get tested for folic acid deficiency?

Wondering if it’s time to check your folate levels? You’re not alone. Many people don’t realize they’re deficient until their doctor runs a blood test for another issue—like anemia or fatigue.

Here’s when you should consider asking for a folic acid blood test:

• You’ve been feeling constantly tired or weak for no clear reason
• You have a digestive condition like celiac disease or IBS
• You’re pregnant or planning to become pregnant
• You’ve been diagnosed with anemia, and iron supplements haven’t helped
• You’re taking medications known to affect nutrient absorption
• You follow a restricted diet (such as vegan or low-carb)
  

Folate levels are measured with a simple blood test—either serum folate (current levels in your blood) or red blood cell folate (longer-term folate status). Both are easy to order through your doctor or local clinic.

How is folic acid deficiency treated?

The good news? Folate deficiency is usually easy to fix once it’s caught.

Most people respond well to a combination of supplements and dietary changes. Here’s what treatment usually looks like:

• Folic acid supplements: These are taken daily, often in doses of 400–1000 micrograms, depending on the severity
• Dietary changes: Adding more folate-rich foods to your meals—like spinach, kale, black beans, oranges, and fortified cereals
  Addressing underlying conditions: If a health issue or medication is causing the deficiency, your provider may adjust your treatment plan
  

Many people start to feel better within just a few weeks of treatment. Energy returns, brain fog lifts, and blood levels gradually return to normal.

How to prevent folic acid deficiency

Even if you’re not currently low in folate, prevention is always better than cure—especially if you're in a high-risk group.

Here are some simple ways to avoid folic acid deficiency:

• Eat a balanced diet: Include plenty of dark green vegetables, beans, nuts, and citrus fruits
• Take a multivitamin or prenatal vitamin, especially if you're pregnant, trying to conceive, or at higher risk for deficiency
• Limit alcohol consumption: Even moderate drinking can lower folate levels over time
• Monitor your health: If you have a digestive disorder or chronic illness, ask your doctor to check your nutrient levels regularly
  

With a few mindful choices, you can keep your folate levels in a healthy range.

Get a folic acid test at a clinic near you

If you’ve been feeling run-down, foggy, or just not like yourself, don’t wait. It’s easy to overlook nutrient deficiencies, but catching them early can make a big difference in how you feel—and how your body functions long-term. Need a folic acid test near you? Solv makes it easy to book an appointment with a clinic or lab in your area. Whether you need a same-day visit or a quick consult, we’ve got you covered.