Vitamin Deficiency Anemia: Symptoms, Causes, Treatment & Complete Guide

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026

Quick Answer

Vitamin deficiency anemia is having too few healthy red blood cells because the body has too little vitamin B-12 and folate, from a poor diet or trouble absorbing and using these vitamins. Without them, the body makes oversized red blood cells that work poorly and carry less oxygen. Vitamin supplements, taken as pills or shots, can fix the condition.

What the research says

• High-dose oral vitamin B-12 raised blood levels about as well as injections in small trials. A Cochrane systematic review of 3 randomized trials (153 participants; 3 to 4 months of follow-up) found that two trials using 1,000 µg/day of oral B-12 showed no clinically relevant difference in serum B-12 levels compared with intramuscular injections, while one trial using 2,000 µg/day showed a mean difference of 680 pg/mL (95% CI 392.7 to 967.3) in favor of oral treatment. The evidence was rated low quality, oral treatment cost less in one trial, and no trial reported clinical signs and symptoms of deficiency. (Wang et al., Cochrane Database Syst Rev, 2018) [3]

• Folic acid before pregnancy lowered the risk of neural tube defects. A Cochrane systematic review of five trials involving 7,391 women found that daily folic acid, alone or combined with other vitamins and minerals, was linked to fewer neural tube defects (risk ratio 0.31, 95% CI 0.17 to 0.58; 5 studies, 6,708 births; high-quality evidence) and fewer recurrences (risk ratio 0.34, 95% CI 0.18 to 0.64; 4 studies, 1,846 births). The effect did not depend on whether the daily dose was 400 µg or higher, and there was no clear effect on cleft palate or other birth defects. (De-Regil et al., Cochrane Database Syst Rev, 2015) [4]

Vitamin Deficiency Anemia at a Glance

Aspect	Summary
Definition	Having too few healthy red blood cells when the body lacks enough vitamin B-12 and folate
Main symptoms	Tiredness, shortness of breath, dizziness, pale or yellow skin, irregular heartbeats, weight loss, numbness or tingling, muscle weakness
Main causes	Not eating enough B-12 or folate foods; trouble absorbing these vitamins (pernicious anemia, gastric surgery, intestinal conditions, alcohol, some medicines)
Who is at risk	People with Crohn's disease, celiac disease, or type 1 diabetes; those who had stomach/intestine surgery; older adults; long-term alcohol users
Key tests	Blood tests for red blood cell number and look, B-12 and folate levels, and intrinsic factor antibodies
Primary treatment	Vitamin supplements — B-12 by shot (sometimes lifelong), pill, sublingual, or nose spray; folate by pill or IV
Outlook	Vitamin supplements taken by pill or shot can fix the condition

What Is Vitamin Deficiency Anemia?

Vitamin deficiency anemia is having too few healthy red blood cells. It happens when the body has too little vitamin B-12 and folate.

There are two routes to this shortage: not eating enough foods that contain these vitamins, or the body having trouble taking in and using them.

Without these nutrients, the body makes red blood cells that are too large and do not work well. As a result, the cells are less able to carry oxygen throughout the body. Symptoms can include tiredness, shortness of breath, and dizziness — and vitamin supplements, taken by pill or in a shot, can fix the condition.

Symptoms of Vitamin Deficiency Anemia

The timeline matters: vitamin B-12 deficiency anemia most often begins slowly over months to years, so you may not notice symptoms at first. Symptoms get worse as the deficiency worsens. Folate deficiency symptoms can start within weeks.

Symptom	What You May Notice
Tiredness	Ongoing exhaustion
Shortness of breath	Feeling winded more easily
Dizziness	Feeling lightheaded
Pale or yellow skin	Harder to see on Black or brown skin
Irregular heartbeats	Heart rhythm that does not feel normal
Weight loss	Unexplained loss
Numbness or tingling	Especially in the hands and feet
Muscle weakness	Reduced strength
Changes in thinking or behaving	Mood or cognitive shifts
Unsteady movements	Balance problems

What Causes Vitamin Deficiency Anemia?

The condition can happen from not eating enough foods with vitamin B-12 and folate, or from the body having trouble taking in and using these vitamins. The two deficiencies have their own cause patterns.

Vitamin B-12 Deficiency

Cause	What Happens
Pernicious anemia	The body's immune system attacks stomach cells that make intrinsic factor — without this substance, the intestines cannot take in B-12
Gastric surgeries	Removing parts of the stomach or intestines lessens intrinsic factor and the area available to absorb B-12
Intestinal conditions	Crohn's disease, celiac disease, and even tapeworms (which eating tainted fish can cause) can block B-12 absorption
Diet	B-12 is mainly in meat, eggs, and milk; people who do not eat these may need supplements — but diet is not often the main cause of B-12 deficiency

Folate Deficiency

Folate, also known as vitamin B-9, is mainly in dark green leafy vegetables and liver. A folate deficiency can happen when people do not eat foods that have folate, or their bodies cannot take in folate from food. The causes include:

• Intestinal conditions, such as celiac disease

• Surgical removal or bypass of a large part of the intestines

• Drinking a lot of alcohol

• A diet low in folate

• Prescription medicines, such as some antiseizure medicines

Two groups also have a greater need for folate: people who are pregnant or breastfeeding, and people who get dialysis for kidney disease.

Not enough folate can cause birth issues during pregnancy. However, folate deficiency is less common in countries where food makers add folate to products such as breads, cereals, and pasta.

Risk Factors

Risk Factor	Why
Certain autoimmune diseases	Crohn's disease, celiac disease, and type 1 diabetes
Stomach or intestine surgery	Removal of part of the stomach or intestines
Older age	Absorption can decline with age
Long-term alcohol use	Interferes with vitamin absorption and intake

Complications of Untreated Vitamin Deficiency Anemia

Not having enough vitamin B-12 or folate raises the risk of several health concerns.

Pregnancy complications matter most with folate: an unborn baby who does not get enough folate during pregnancy can have brain and spinal cord conditions present at birth.

Nervous system conditions come with B-12: the brain needs vitamin B-12 to work well. If a B-12 deficiency is not treated, it can lead to issues with the nerves, brain, or spinal cord — including lasting tingling in the hands and feet or trouble with balance.

Cancer risk is tied to pernicious anemia, which raises the risk of stomach or intestinal cancer.

Prevention: Foods and Daily Amounts

You can prevent some forms of vitamin deficiency anemia by choosing a healthy diet that includes a wide range of foods.

Foods Rich in Vitamin B-12

• Beef, liver, chicken, and fish

• Eggs

• Fortified foods — foods with vitamin B-12 added, including many breakfast cereals

• Milk, cheese, and yogurt

Foods Rich in Folate

• Broccoli, spinach, asparagus, and lima beans

• Oranges, lemons, bananas, strawberries, and melons

• Enriched grain products — bread, cereal, pasta, and rice

• Liver, kidney, yeast, mushrooms, and peanuts

How Much You Need Daily

Vitamin	Daily Amount for Most Adults
Vitamin B-12	2.4 micrograms (mcg)
Folate or folic acid	400 mcg

People who are pregnant or breastfeeding may need more of each vitamin.

Most people get enough vitamins from the foods they eat. But if you limit what you eat or you have had gastric bypass surgery, you may want to take a multivitamin.

How Is Vitamin Deficiency Anemia Diagnosed?

To diagnose vitamin deficiency anemia, blood tests check for:

1. The number and look of red blood cells

2. The amount of vitamin B-12 and folate in the blood

3. Antibodies to intrinsic factor, which indicates pernicious anemia — antibodies are proteins the immune system makes to fight off invaders

Treatment for Vitamin Deficiency Anemia

Treatment involves taking the vitamin you do not have enough of. The form depends on the underlying cause.

Vitamin B-12

For pernicious anemia, you most often get vitamin B-12 in a shot — and you may need to keep getting the shot for the rest of your life, because the body cannot absorb B-12 through the gut.

Vitamin B-12 comes in four forms:

Form	How It Is Taken
Shots	Into a muscle or under the skin
Pills	Taken by mouth
Sublingual	A liquid or tablet that dissolves under the tongue
Nose gel or sprays	Applied inside the nose

Folate

Medicines to boost folate levels most often come as pills taken by mouth, but some people get folic acid through a tube into a vein.

Preparing for Your Appointment

Start by seeing your main healthcare professional, who may send you to a specialist in blood conditions called a hematologist.

Before you go, make a list of:

1. Your symptoms and when they began

2. Key medical information, including other conditions you have

3. All medicines, vitamins, and supplements you take, including dosages

4. Questions to ask your healthcare professional

Questions to Ask

• What's the most likely cause of my symptoms?

• What else could cause my symptoms?

• Is my condition likely to go away or to last?

• What treatment do you suggest?

• I have another health condition. How can I best manage these conditions together?

• What foods do I need to add to my diet?

• Where can I find more information about vitamin deficiency anemia?

Be sure to ask all the questions you have.

What Your Doctor Will Ask

• How bad are your symptoms?

• Does anything seem to make your symptoms better?

• Does anything seem to make your symptoms worse?

• Are you a vegetarian or a vegan?

• Do you drink alcohol? If so, how often, and how many drinks do you have?

• Do you use tobacco products?

Frequently Asked Questions

What is vitamin deficiency anemia?

Vitamin deficiency anemia is having too few healthy red blood cells. It happens when the body has too little vitamin B-12 and folate, which the body needs to make red blood cells that work properly.

What are the symptoms of vitamin deficiency anemia?

Symptoms include tiredness, shortness of breath, dizziness, pale or yellow skin, irregular heartbeats, weight loss, numbness or tingling in the hands and feet, muscle weakness, changes in thinking or behaving, and unsteady movements.

What causes vitamin B-12 deficiency?

The main causes are pernicious anemia (the immune system attacks stomach cells that make intrinsic factor), gastric surgery, intestinal conditions such as Crohn's disease and celiac disease, tapeworms, and — rarely — a diet low in meat, eggs, and milk.

What causes folate deficiency?

Folate deficiency can come from intestinal conditions like celiac disease, removal or bypass of part of the intestines, heavy alcohol use, a low-folate diet, and some prescription medicines such as certain antiseizure drugs. Pregnant, breastfeeding, and dialysis patients also need more folate.

How is vitamin deficiency anemia diagnosed?

Blood tests check the number and appearance of red blood cells, the amount of vitamin B-12 and folate in the blood, and antibodies to intrinsic factor, which indicate pernicious anemia.

How is vitamin deficiency anemia treated?

Treatment is taking the missing vitamin — vitamin B-12 by shot, pill, sublingual tablet, or nose spray, and folate mostly by mouth pills. People with pernicious anemia often need lifelong B-12 shots.

Can vitamin deficiency anemia cause permanent damage?

Yes, if untreated. Low B-12 can lead to lasting tingling in the hands and feet and balance trouble from nerve, brain, or spinal cord damage, and pernicious anemia raises the risk of stomach or intestinal cancer. Not enough folate during pregnancy can cause brain and spinal cord conditions in a newborn.

Conclusion

The three lessons to carry away from this guide:

• Two vitamins drive this anemia — too little vitamin B-12 or folate produces red blood cells that are too large and cannot carry oxygen well.

• B-12 deficiency creeps up slowly over months to years, while folate deficiency can show within weeks, so the timeline of your symptoms is a valuable clue.

• Treatment works — taking the missing vitamin by pill, spray, or shot can fix the condition, though pernicious anemia may require lifelong B-12 shots.

This guide has walked you through the ten signs to watch for, the separate cause patterns for each vitamin, the daily amounts your body needs, the foods that deliver them, and the blood tests and treatments that restore your levels. Recognizing vitamin deficiency anemia early protects your nerves, your heart, and — for expecting parents — a baby's development.

Your Next Steps

• Share your thoughts — Have you or someone you love dealt with low B-12 or folate? Leave a comment below — your experience may help another reader.

Disclaimer: This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

Related Reading

Learn more in our guide to Hemoglobin Test: Normal Ranges, Results and What They Mean.

Methylmalonic Acid (MMA) Test: Normal Range, High MMA and Vitamin B12 explains the test that shows whether your body is truly short of vitamin B12.

References

1. Mayo Clinic Staff. Vitamin deficiency anemia - Symptoms & causes. Mayo Clinic. September 16, 2025. https://www.mayoclinic.org/diseases-conditions/vitamin-deficiency-anemia/symptoms-causes/syc-20355025

2. Mayo Clinic Staff. Vitamin deficiency anemia - Diagnosis & treatment. Mayo Clinic. September 16, 2025. https://www.mayoclinic.org/diseases-conditions/vitamin-deficiency-anemia/diagnosis-treatment/drc-20355031

3. Wang H, et al. Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency. Cochrane Database Syst Rev. 2018;3(3):CD004655. PMID 29543316. https://doi.org/10.1002/14651858.CD004655.pub3

4. De-Regil LM, et al. Effects and safety of periconceptional oral folate supplementation for preventing birth defects. Cochrane Database Syst Rev. 2015;2015(12):CD007950. PMID 26662928. https://doi.org/10.1002/14651858.CD007950.pub3