Overview

Vitamin deficiency anemia is a lack of healthy red blood cells caused by lower than usual amounts of vitamin B-12 and folate.

This can happen if you don't eat enough foods containing vitamin B-12 and folate, or if your body has trouble absorbing or processing these vitamins.

Without these nutrients, the body produces red blood cells that are too large and don't work properly. This reduces their ability to carry oxygen.

Symptoms can include fatigue, shortness of breath and dizziness. Vitamin supplements, taken by pill or injection, can correct the deficiencies.

Symptoms

Vitamin deficiency anemia usually develops slowly over several months to years. Signs and symptoms may be subtle at first but usually increase as the deficiency worsens. These may include:

  • Fatigue
  • Shortness of breath
  • Dizziness
  • Pale or yellowish skin
  • Irregular heartbeats
  • Weight loss
  • Numbness or tingling in the hands and feet
  • Muscle weakness
  • Personality changes
  • Unsteady movements
  • Mental confusion or forgetfulness

Causes

Vitamin deficiency anemia can occur if you don't eat enough foods containing vitamin B-12 and folate, or if your body has trouble absorbing or processing these vitamins.

Vitamin B-12 deficiencies

Low levels of vitamin B-12 can be caused by:

  • Diet. Vitamin B-12 is mainly found in meat, eggs and milk, so people who don't eat these types of foods may need to take B-12 supplements. Some foods have been fortified with B-12, including some breakfast cereals and some nutritional yeast products.
  • Pernicious anemia. This condition occurs when the body's immune system attacks cells in the stomach that produce a substance called intrinsic factor. Without this substance, B-12 can't be absorbed in the intestines.
  • Gastric surgeries. If portions of your stomach or intestines have been surgically removed, that can reduce the amount of intrinsic factor produced and the amount of space available for vitamin B-12 to be absorbed.
  • Intestinal problems. Crohn's disease and celiac disease can interfere with absorption of vitamin B-12, as can tapeworms that may be ingested from eating contaminated fish.

Folate deficiencies

Also known as vitamin B-9, folate is a nutrient found mainly in dark green leafy vegetables and liver. A folate deficiency can occur when people don't eat foods containing folate or their bodies are unable to absorb folate from food.

Absorption problems may be caused by:

  • Intestinal diseases such as celiac disease
  • Surgical removal or bypass of a large part of the intestines
  • Excessive alcohol consumption
  • Prescription drugs, such as some anti-seizure medications

Pregnant women and women who are breastfeeding have an increased demand for folate, as do people undergoing dialysis for kidney disease.

A lack of folate can cause birth defects during pregnancy. However, folate deficiency is less common now in countries that routinely add folate to food products such as breads, cereals and pasta.

Complications

Being deficient in vitamin B-12 or folate increases your risk of many health problems, including:

  • Pregnancy complications. A developing fetus that doesn't get enough folate from its mother can develop birth defects of the brain and spinal cord.
  • Nervous system disorders. Untreated, vitamin B-12 deficiency can lead to neurological problems, such as persistent tingling in the hands and feet or problems with balance. It can lead to mental confusion and forgetfulness because vitamin B-12 is necessary for healthy brain function.
  • Gastric cancer. Pernicious anemia increases the risk of stomach or intestinal cancers.

Prevention

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

Foods rich in vitamin B-12 include:

  • Beef, liver, chicken and fish
  • Eggs
  • Fortified foods, such as breakfast cereals
  • Milk, cheese and yogurt

Foods rich in folate include:

  • Broccoli, spinach, asparagus and lima beans
  • Oranges, lemons, bananas, strawberries and melons
  • Enriched grain products, such as bread, cereal, pasta and rice
  • Liver, kidneys, yeast, mushrooms and peanuts

Most adults need these daily dietary amounts of the following vitamins:

  • Vitamin B-12 — 2.4 micrograms (mcg)
  • Folate or folic acid — 400 mcg

Pregnant and breastfeeding women may require more of each vitamin.

Most people get enough vitamins from the foods they eat. But if your diet is restricted or you've had gastric bypass surgery, you may wish to take a multivitamin.

Jan. 18, 2022
  1. Kellerman RD, et al. Pernicious anemia/megaloblastic anemia. In: Conn's Current Therapy 2021. Elsevier; 2021. https://www.clinicalkey.com. Accessed Aug. 18, 2021.
  2. Megaloblastic macrocytic anemias. Merck Manual Professional Version. https://www.merckmanuals.com/professional/hematology-and-oncology/anemias-caused-by-deficient-erythropoiesis/megaloblastic-macrocytic-anemias?query=vitamin%20deficiency%20anemia. Accessed Aug. 18, 2021.
  3. Means RT, et al. Clinical manifestations and diagnosis of vitamin B12 and folate deficiency. https://www.uptodate.com/contents/search. Accessed Aug. 18, 2021.
  4. Means RT, et al. Causes and pathophysiology of vitamin B12 and folate deficiency. https://www.uptodate.com/contents/search. Accessed Aug. 18, 2021.
  5. Goldman L, et al., eds. Approach to the anemias. In: Goldman-Cecil Medicine. 26th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Aug. 18, 2021.
  6. AskMayoExpert. Pernicious anemia. Mayo Clinic; 2021.
  7. Kaushansky K, et al., eds. Folate, cobalamin, and megaloblastic anemias. In: Williams Hematology. 10th ed. McGraw Hill; 2021. https://accessmedicine.mhmedical.com. Accessed Aug. 18, 2021.
  8. Pernicious anemia. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health-topics/pernicious-anemia. Accessed Aug. 18, 2021.
  9. 2020-2025 Dietary Guidelines for Americans. U.S. Department of Health and Human Services and U.S. Department of Agriculture. https://www.dietaryguidelines.gov. Accessed Oct. 21, 2021.
  10. Means RT, et al. Treatment of vitamin B12 and folate deficiency. https://www.uptodate.com/contents/search. Accessed Aug. 18, 2021.
  11. Vitamin B12: Fact sheet for health professionals. National Institutes of Health Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional. Accessed Oct. 4, 2021.