BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuVitamin B12 deficiency anemiaMegaloblastic macrocytic anemia; Cobalamin deficiency anemiaAnemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are many types of anemia.AnemiaAnemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Different type...ImageRead Article Now Book Mark Article Related video goes here for no-HTML5 browsersVitamin B12 deficiency anemia is a low red blood cell count due to a lack (deficiency) of vitamin B12.Vitamin B12Vitamin B12 is a water-soluble vitamin. Water-soluble vitamins dissolve in water. After the body uses what it needs of these vitamins, leftover amo...ImageRead Article Now Book Mark Article Causes Your body needs vitamin B12 to make red blood cells. In order to provide vitamin B12 to your cells:You must eat foods that contain vitamin B12, such as meat, poultry, shellfish, eggs, fortified breakfast cereals, and dairy products. Your body must absorb enough vitamin B12. A special protein, called intrinsic factor, helps your body do this efficiently. This protein is released by cells in the stomach.Certain health conditions can make it difficult for your body to absorb enough vitamin B12. They include:Pernicious anemia, a condition that occurs when your body destroys cells in your stomach that make intrinsic factor, which may lead to vitamin B12 deficiency and anemia Pernicious anemiaAnemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are man...ImageRead Article Now Book Mark Article Surgery that removes certain parts of your stomach or small intestine, such as some weight-loss surgeries Crohn disease, celiac disease, infection with the fish tapeworm, or other problems that make it difficult for your body to digest foods Crohn diseaseCrohn disease is a disease where parts of the digestive tract become inflamed. It most often involves the lower end of the small intestine and the be...ImageRead Article Now Book Mark Article Celiac diseaseCeliac disease is an autoimmune condition that damages the lining of the small intestine. This damage comes from a reaction to eating gluten. This ...ImageRead Article Now Book Mark Article Alcohol use Taking antacids and other heartburn medicines for a long period of time Abuse of laughing gas (nitrous oxide) Long term use of the medicine metforminA lack of vitamin B12 may be due to dietary factors, including:Eating a strict vegetarian diet Poor diet in infants Poor nutrition during pregnancy Symptoms You may not have symptoms. Symptoms may be mild. Symptoms may include: Diarrhea or constipation DiarrheaDiarrhea is when you pass loose or watery stool.ImageRead Article Now Book Mark Article Fatigue, lack of energy, or lightheadedness when standing up or with exertion FatigueFatigue is a feeling of weariness, tiredness, or lack of energy.ImageRead Article Now Book Mark Article Loss of appetite Loss of appetiteA decreased appetite is when your desire to eat is reduced. The medical term for a loss of appetite is anorexia.ImageRead Article Now Book Mark Article Pale skin Pale skinPaleness is an abnormal loss of color from normal skin or mucous membranes.ImageRead Article Now Book Mark Article Feeling irritable Shortness of breath, mostly during exercise Shortness of breathBreathing difficulty may involve:Difficult breathing Uncomfortable breathingFeeling like you are not getting enough airImageRead Article Now Book Mark Article Swollen, red tongue or bleeding gums If you have low vitamin B12 level for a long time, it can cause nerve damage. Symptoms of nerve damage include: Numbness and tingling of hands and feet Loss of balance Problems concentrating Confusion or change in mental status (dementia) in severe cases DementiaDementia is loss of brain function that occurs with certain diseases. Dementia may also be referred to as major neurocognitive disorder. Dementia du...ImageRead Article Now Book Mark Article Psychosis (losing contact with reality) PsychosisPsychosis occurs when a person loses contact with reality. The person may: Have false beliefs about what is taking place, or who one is (delusions)S...Read Article Now Book Mark Article HallucinationsHallucinationsHallucinations involve sensing things such as visions, sounds, or smells that seem real but are not. These things are created by the mind.ImageRead Article Now Book Mark Article Exams and Tests The health care provider will perform a physical exam. This may reveal problems with your reflexes or sensations. Tests that may be done include: Complete blood count (CBC) Complete blood countA complete blood count (CBC) test measures the following:The number of white blood cells (WBC count)The number of red blood cells (RBC count)The numb...ImageRead Article Now Book Mark Article Reticulocyte count Reticulocyte countReticulocytes are slightly immature red blood cells. A reticulocyte count is a blood test that measures the amount of these cells in the blood....ImageRead Article Now Book Mark Article Lactate dehydrogenase (LDH) level Lactate dehydrogenaseLactate dehydrogenase (LDH) is a protein that helps produce energy in the body. An LDH test measures the amount of LDH in the blood.ImageRead Article Now Book Mark Article Serum bilirubin level Serum vitamin B12 level Serum vitamin B12 levelThe vitamin B12 level is a blood test that measures how much vitamin B12 is in your blood.ImageRead Article Now Book Mark Article Serum methylmalonic acid (MMA) level Serum methylmalonic acidThe methylmalonic acid blood test measures the amount of methylmalonic acid in the blood.ImageRead Article Now Book Mark Article Serum homocysteine level (amino acid found in blood) Anti-intrinsic factor antibody Anti-parietal cell antibodyAnti-parietal cell antibodyAn antiparietal cell antibody test is a blood test that looks for antibodies against the parietal cells of the stomach. The parietal cells make and ...ImageRead Article Now Book Mark Article Other procedures that may be done include:Esophagogastroduodenoscopy (EGD) to examine the stomach and small intestine EsophagogastroduodenoscopyEsophagogastroduodenoscopy (EGD) is a test to examine the lining of the esophagus, stomach, and first part of the small intestine (the duodenum)....ImageRead Article Now Book Mark Article Bone marrow biopsy if the diagnosis is not clear Bone marrow biopsyA bone marrow biopsy is the removal of marrow from inside one of your bones. Bone marrow is the soft tissue inside bones that helps form blood cells...ImageRead Article Now Book Mark Article Treatment Treatment depends on the cause of B12 deficiency anemia. The goal of treatment is to increase your vitamin B12 level.For people who have a low level of B12 due to a restricted vegetarian diet, taking B12 pills may resolve the issue. For people with a health condition that causes B12 deficiency, treatment may include a shot of vitamin B12, often once a month. If you have a very low level of B12, you may need more shots in the beginning. It is possible you may need shots regularly for the rest of your life.Your provider will also recommend that you eat a variety of foods. Outlook (Prognosis) People with this type of anemia often do well with treatment.Long-term vitamin B12 deficiency can cause nerve damage. This may be permanent if you do not start treatment promptly after your symptoms begin. If nerve damage is severe or long-lasting, some damage may be permanent.Vitamin B12 deficiency anemia most often responds well to treatment. It will likely get better when the underlying cause of the deficiency is treated. Possible Complications A woman with a low B12 level may have a false positive Pap smear. This is because vitamin B12 deficiency affects the way certain cells (epithelial cells) in the cervix look. When to Contact a Medical Professional Contact your provider if you have any of the symptoms of anemia. Prevention Eating a well-balanced diet can help ensure you get enough vitamin B12 from the foods you eat. However, it can't prevent anemia in people with certain health conditions that prevent their body from using vitamin B12 properly.Shots of vitamin B12 can prevent anemia if you've had a surgery known to cause vitamin B12 deficiency.Early diagnosis and prompt treatment can reduce or prevent complications related to a low vitamin B12 level.There is no evidence that taking B12 supplements will prevent or treat dementia, Alzheimer disease, or other health conditions such as heart disease.Open ReferencesReferencesAntony AC. Megaloblastic anemias. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 40.Means Jr. RT. Approach to the anemias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 144.National Institutes of Health website. Vitamin B12: fact sheet for health professionals. ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/. Updated March 26, 2024. Accessed August 17, 2024.Stabler SP. Megaloblastic anemias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 150.AllVideoImagesTogMegaloblastic anemia - view of red blood cells - illustration This picture shows large, dense, oversized, red blood cells (RBCs) that are seen in megaloblastic anemia. Megaloblastic anemia can occur when there is a deficiency of vitamin B-12.Megaloblastic anemia - view of red blood cellsillustrationHypersegmented PMN (Close-up) - illustration This image shows a large polymorphonuclear leukocyte (PMN) with multiple discretely-identifiable nuclear lobes. It can be seen in megaloblastic anemias. Normal PMN's have less than or equal to 5 lobes.Hypersegmented PMN (Close-up)illustrationMegaloblastic anemia - view of red blood cells - illustration This picture shows large, dense, oversized, red blood cells (RBCs) that are seen in megaloblastic anemia. Megaloblastic anemia can occur when there is a deficiency of vitamin B-12.Megaloblastic anemia - view of red blood cellsillustrationHypersegmented PMN (Close-up) - illustration This image shows a large polymorphonuclear leukocyte (PMN) with multiple discretely-identifiable nuclear lobes. It can be seen in megaloblastic anemias. Normal PMN's have less than or equal to 5 lobes.Hypersegmented PMN (Close-up)illustrationA Closer Look Vitamin B12 (Cobalamin)(Alt. Medicine)Vitamins and Phytonutrients - InDepth(In-Depth)Anemia(Alt. Medicine)Anemia - InDepth(In-Depth)Vitamin B6 (Pyridoxine)(Alt. Medicine)Antibiotic medications - aminoglycosides(Alt. Medicine)Sickle cell disease - InDepth(In-Depth)Stroke(Alt. Medicine)Calcium(Alt. Medicine)Crohn disease(Alt. Medicine) Tests for Vitamin B12 deficiency anemia Vitamin B12 levelTotal iron binding capacityCBC blood testRBC countFolic acid - testRelated Information Vitamin B12(Nutrition)Intrinsic factor(Special Topic)Chronic(Special Topic)Crohn disease(Condition)Malabsorption(Condition)Pernicious anemia(Condition)Central nervous system(Special Topic)Pap test(Medical Test)Vitamins and Phytonutrients - InDepth(In-Depth)Anemia - InDepth(In-Depth)Crohn disease - InDepth(In-Depth) Review Date: 3/31/2024 Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. Editorial update 08/19/2024. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. © 1997- All rights reserved. A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.Content is best viewed in IE9 or above, Firefox and Google Chrome browser.
Vitamin B12 deficiency anemiaMegaloblastic macrocytic anemia; Cobalamin deficiency anemiaAnemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are many types of anemia.AnemiaAnemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Different type...ImageRead Article Now Book Mark Article Related video goes here for no-HTML5 browsersVitamin B12 deficiency anemia is a low red blood cell count due to a lack (deficiency) of vitamin B12.Vitamin B12Vitamin B12 is a water-soluble vitamin. Water-soluble vitamins dissolve in water. After the body uses what it needs of these vitamins, leftover amo...ImageRead Article Now Book Mark Article Causes Your body needs vitamin B12 to make red blood cells. In order to provide vitamin B12 to your cells:You must eat foods that contain vitamin B12, such as meat, poultry, shellfish, eggs, fortified breakfast cereals, and dairy products. Your body must absorb enough vitamin B12. A special protein, called intrinsic factor, helps your body do this efficiently. This protein is released by cells in the stomach.Certain health conditions can make it difficult for your body to absorb enough vitamin B12. They include:Pernicious anemia, a condition that occurs when your body destroys cells in your stomach that make intrinsic factor, which may lead to vitamin B12 deficiency and anemia Pernicious anemiaAnemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are man...ImageRead Article Now Book Mark Article Surgery that removes certain parts of your stomach or small intestine, such as some weight-loss surgeries Crohn disease, celiac disease, infection with the fish tapeworm, or other problems that make it difficult for your body to digest foods Crohn diseaseCrohn disease is a disease where parts of the digestive tract become inflamed. It most often involves the lower end of the small intestine and the be...ImageRead Article Now Book Mark Article Celiac diseaseCeliac disease is an autoimmune condition that damages the lining of the small intestine. This damage comes from a reaction to eating gluten. This ...ImageRead Article Now Book Mark Article Alcohol use Taking antacids and other heartburn medicines for a long period of time Abuse of laughing gas (nitrous oxide) Long term use of the medicine metforminA lack of vitamin B12 may be due to dietary factors, including:Eating a strict vegetarian diet Poor diet in infants Poor nutrition during pregnancy Symptoms You may not have symptoms. Symptoms may be mild. Symptoms may include: Diarrhea or constipation DiarrheaDiarrhea is when you pass loose or watery stool.ImageRead Article Now Book Mark Article Fatigue, lack of energy, or lightheadedness when standing up or with exertion FatigueFatigue is a feeling of weariness, tiredness, or lack of energy.ImageRead Article Now Book Mark Article Loss of appetite Loss of appetiteA decreased appetite is when your desire to eat is reduced. The medical term for a loss of appetite is anorexia.ImageRead Article Now Book Mark Article Pale skin Pale skinPaleness is an abnormal loss of color from normal skin or mucous membranes.ImageRead Article Now Book Mark Article Feeling irritable Shortness of breath, mostly during exercise Shortness of breathBreathing difficulty may involve:Difficult breathing Uncomfortable breathingFeeling like you are not getting enough airImageRead Article Now Book Mark Article Swollen, red tongue or bleeding gums If you have low vitamin B12 level for a long time, it can cause nerve damage. Symptoms of nerve damage include: Numbness and tingling of hands and feet Loss of balance Problems concentrating Confusion or change in mental status (dementia) in severe cases DementiaDementia is loss of brain function that occurs with certain diseases. Dementia may also be referred to as major neurocognitive disorder. Dementia du...ImageRead Article Now Book Mark Article Psychosis (losing contact with reality) PsychosisPsychosis occurs when a person loses contact with reality. The person may: Have false beliefs about what is taking place, or who one is (delusions)S...Read Article Now Book Mark Article HallucinationsHallucinationsHallucinations involve sensing things such as visions, sounds, or smells that seem real but are not. These things are created by the mind.ImageRead Article Now Book Mark Article Exams and Tests The health care provider will perform a physical exam. This may reveal problems with your reflexes or sensations. Tests that may be done include: Complete blood count (CBC) Complete blood countA complete blood count (CBC) test measures the following:The number of white blood cells (WBC count)The number of red blood cells (RBC count)The numb...ImageRead Article Now Book Mark Article Reticulocyte count Reticulocyte countReticulocytes are slightly immature red blood cells. A reticulocyte count is a blood test that measures the amount of these cells in the blood....ImageRead Article Now Book Mark Article Lactate dehydrogenase (LDH) level Lactate dehydrogenaseLactate dehydrogenase (LDH) is a protein that helps produce energy in the body. An LDH test measures the amount of LDH in the blood.ImageRead Article Now Book Mark Article Serum bilirubin level Serum vitamin B12 level Serum vitamin B12 levelThe vitamin B12 level is a blood test that measures how much vitamin B12 is in your blood.ImageRead Article Now Book Mark Article Serum methylmalonic acid (MMA) level Serum methylmalonic acidThe methylmalonic acid blood test measures the amount of methylmalonic acid in the blood.ImageRead Article Now Book Mark Article Serum homocysteine level (amino acid found in blood) Anti-intrinsic factor antibody Anti-parietal cell antibodyAnti-parietal cell antibodyAn antiparietal cell antibody test is a blood test that looks for antibodies against the parietal cells of the stomach. The parietal cells make and ...ImageRead Article Now Book Mark Article Other procedures that may be done include:Esophagogastroduodenoscopy (EGD) to examine the stomach and small intestine EsophagogastroduodenoscopyEsophagogastroduodenoscopy (EGD) is a test to examine the lining of the esophagus, stomach, and first part of the small intestine (the duodenum)....ImageRead Article Now Book Mark Article Bone marrow biopsy if the diagnosis is not clear Bone marrow biopsyA bone marrow biopsy is the removal of marrow from inside one of your bones. Bone marrow is the soft tissue inside bones that helps form blood cells...ImageRead Article Now Book Mark Article Treatment Treatment depends on the cause of B12 deficiency anemia. The goal of treatment is to increase your vitamin B12 level.For people who have a low level of B12 due to a restricted vegetarian diet, taking B12 pills may resolve the issue. For people with a health condition that causes B12 deficiency, treatment may include a shot of vitamin B12, often once a month. If you have a very low level of B12, you may need more shots in the beginning. It is possible you may need shots regularly for the rest of your life.Your provider will also recommend that you eat a variety of foods. Outlook (Prognosis) People with this type of anemia often do well with treatment.Long-term vitamin B12 deficiency can cause nerve damage. This may be permanent if you do not start treatment promptly after your symptoms begin. If nerve damage is severe or long-lasting, some damage may be permanent.Vitamin B12 deficiency anemia most often responds well to treatment. It will likely get better when the underlying cause of the deficiency is treated. Possible Complications A woman with a low B12 level may have a false positive Pap smear. This is because vitamin B12 deficiency affects the way certain cells (epithelial cells) in the cervix look. When to Contact a Medical Professional Contact your provider if you have any of the symptoms of anemia. Prevention Eating a well-balanced diet can help ensure you get enough vitamin B12 from the foods you eat. However, it can't prevent anemia in people with certain health conditions that prevent their body from using vitamin B12 properly.Shots of vitamin B12 can prevent anemia if you've had a surgery known to cause vitamin B12 deficiency.Early diagnosis and prompt treatment can reduce or prevent complications related to a low vitamin B12 level.There is no evidence that taking B12 supplements will prevent or treat dementia, Alzheimer disease, or other health conditions such as heart disease.Open ReferencesReferencesAntony AC. Megaloblastic anemias. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 40.Means Jr. RT. Approach to the anemias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 144.National Institutes of Health website. Vitamin B12: fact sheet for health professionals. ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/. Updated March 26, 2024. Accessed August 17, 2024.Stabler SP. Megaloblastic anemias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 150.
