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Vitamin-Deficiency Anemias (B12 / B9)

Overview

Vitamin‑deficiency anemias occur when the body doesn’t have enough vitamin B12 or folate (vitamin B9) to make healthy red blood cells. Without these vitamins, the body begins producing red blood cells that are too large and don’t work properly, reducing their ability to carry oxygen.

This leads to fatigue, shortness of breath, dizziness, and other symptoms. Vitamin‑deficiency anemias often develop gradually and worsen over time if not treated.

What Causes Vitamin‑Deficiency Anemia?

Vitamin B12 Deficiency

You may develop B12 deficiency if your body doesn’t take in or absorb enough vitamin B12. Common causes include:

  • Pernicious anemia, an autoimmune condition where the body cannot make intrinsic factor, a stomach protein needed for B12 absorption.
  • Digestive conditions (e.g., Crohn’s disease, celiac disease) or intestinal surgeries that limit absorption.
  • Lack of dietary B12, more common in strict vegetarians or vegans.
  • Older age, alcohol misuse, or long‑term use of certain medications that reduce stomach acid.

Folate (Vitamin B9) Deficiency

Folate deficiency can occur when the body’s folate needs increase or when dietary intake is too low. Causes include:

  • Diets low in folate
  • Digestive conditions that reduce absorption
  • Alcohol misuse or certain medications that interfere with folate processing

Signs and Symptoms

Common Symptoms (Both B12 & Folate Deficiency)

Symptoms often begin gradually and may worsen over months to years. They can include:

  • Fatigue or low energy
  • Pale or yellow‑tinged skin
  • Shortness of breath
  • Dizziness
  • Irregular heartbeat
  • Weight loss

Neurologic Symptoms (More Common in B12 Deficiency)

Vitamin B12 is essential for nerve health. Untreated deficiency may lead to:

  • Numbness or tingling in hands or feet
  • Muscle weakness
  • Balance problems
  • Difficulty walking
  • Changes in thinking or behavior
  • Memory loss or confusion

Symptoms in Folate Deficiency

Folate deficiency symptoms may develop quickly (within weeks) and include:

  • Fatigue
  • Irritability
  • Shortness of breath

How We Diagnose Vitamin‑Deficiency Anemias

Diagnosis begins with a complete blood count (CBC), which may show large red blood cells (macrocytosis).

Blood tests also measure:

  • Vitamin B12 levels and folate levels
  • Additional tests (e.g., intrinsic factor antibodies, methylmalonic acid) if B12 absorption problems are suspected

Treatment Options

Treating vitamin‑deficiency anemia means replacing the missing nutrient:

  • Vitamin B12 can be given orally, nasally, or through intramuscular injections, especially in pernicious anemia or severe deficiency.
  • Folate supplements (folic acid) are taken orally.

Eating foods rich in B12 and folate supports recovery:

  • Vitamin B12 sources: meat, eggs, dairy, fish, fortified cereals
  • Folate sources: leafy greens, legumes, citrus fruits, whole grains

If a digestive disorder, surgery, or autoimmune condition is limiting vitamin absorption, your care team will work with you to manage those conditions.

Prevention

Many cases of vitamin‑deficiency anemia can be prevented by:

Eating a balanced diet with adequate B12 and folate

Considering supplements if you follow a vegetarian/vegan diet or have absorption issues

Seeking evaluation for persistent fatigue, neurological symptoms, or unexplained anemia

When To See Your Provider

Contact us right away if you experience:

Persistent fatigue

New numbness or tingling in hands/feet

Difficulty walking or balance problems

Chest pain

Shortness of breath or rapid heartbeat

Sudden behavior or memory changes

Why Choose Illinois CancerCare

A blood disorder diagnosis can feel overwhelming. At Illinois CancerCare, we are committed to ensuring you never have to face it alone. Providing advanced, comprehensive hematology and oncology care for our patients is at the heart of everything we do. Since 1977, our specialists have focused on individualized, evidence-based treatment plans, access to world-class clinical trials, and thorough follow-up. With Illinois CancerCare, you can move forward with confidence knowing trusted expertise and compassionate support are always close to home.‑based treatment plans, access to world‑class clinical trials, and thorough follow‑up.

Sources & Patient Friendly References

Information sourced from NIH (National Institute of Health), Mayo Clinic, and Johns Hopkins Medicine.