Cobalamin (Vitamin B12) •

Cobalamin (Vitamin B12)


What is Cobalamin (Vitamin B12)?

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a crucial role in the functioning of the nervous system and the formation of red blood cells. It is a member of the B-complex group of vitamins.

Here are some key functions and features of vitamin B12:

  1. Red Blood Cell Formation: Vitamin B12 is essential for the production of red blood cells in the bone marrow. Red blood cells are responsible for carrying oxygen throughout the body.
  2. Nervous System Function: B12 is vital for maintaining the health of the nervous system. It helps in the production of myelin, a protective sheath that covers nerve fibers and allows proper nerve function.
  3. DNA Synthesis: Vitamin B12 is involved in the synthesis of DNA, the genetic material present in cells. It is necessary for cell division and growth.
  4. Energy Metabolism: B12 aids in the metabolism of fats and carbohydrates, converting food into energy.
  5. Dietary Sources: Vitamin B12 is primarily found in animal-based foods, such as meat, fish, eggs, dairy products, and fortified cereals. Plants do not naturally contain vitamin B12, so vegetarians and vegans may need to rely on fortified foods or supplements to meet their B12 requirements.
  6. Absorption: Vitamin B12 requires a specific protein called intrinsic factor, which is produced in the stomach, for absorption in the small intestine. Certain medical conditions, medications, or digestive system issues can affect the absorption of vitamin B12.
  7. Recommended Daily Intake: The recommended daily intake of vitamin B12 varies by age, sex, and life stage. For adults, the recommended daily intake is typically around 2.4 micrograms (mcg). Pregnant and breastfeeding women may need slightly more.
  8. Deficiency: A deficiency in vitamin B12 can lead to anemia (a decrease in red blood cells), fatigue, weakness, constipation, loss of appetite, weight loss, poor memory, and neurological issues such as tingling or numbness in the hands and feet. Long-term deficiency can cause irreversible damage to the nervous system.
  9. Supplementation: Vitamin B12 supplements are often recommended for individuals at risk of deficiency, including vegetarians, vegans, older adults, and those with certain medical conditions affecting absorption.

It’s important to ensure an adequate intake of vitamin B12 through a balanced diet that includes animal products or fortified foods, or through supplementation when necessary. If you have concerns about your vitamin B12 levels or potential deficiency, it’s advisable to consult a healthcare professional for appropriate guidance and testing.

What are the recommended dietary guidelines for Cobalamin (Vitamin B12)?

The recommended dietary guidelines for vitamin B12 can vary slightly depending on factors such as age, sex, life stage, and individual health conditions. Here are general recommendations for vitamin B12 intake based on the guidelines set by the United States National Institutes of Health (NIH):

  1. Infants:
    • 0-6 months: 0.4 micrograms (mcg) per day
    • 7-12 months: 0.5 mcg per day
  2. Children:
    • 1-3 years: 0.9 mcg per day
    • 4-8 years: 1.2 mcg per day
    • 9-13 years: 1.8 mcg per day
  3. Adolescents and Adults:
    • Males and females (14 years and older): 2.4 mcg per day
  4. Pregnant and Breastfeeding Women:
    • Pregnant teens (14-18 years): 2.6 mcg per day
    • Pregnant adults (19 years and older): 2.6 mcg per day
    • Breastfeeding teens (14-18 years): 2.8 mcg per day
    • Breastfeeding adults (19 years and older): 2.8 mcg per day

It’s important to note that these recommendations are for generally healthy individuals. People with certain health conditions, vegetarians, vegans, and individuals with gastrointestinal disorders that affect absorption may need higher doses or should consider supplementation.

For those following a vegetarian or vegan diet, or individuals with limited intake of animal-based products, obtaining vitamin B12 from fortified foods or supplements is important to meet their requirements.

As always, it’s advisable to consult with a healthcare professional or a registered dietitian to determine the appropriate vitamin B12 intake based on individual circumstances and dietary choices. They can also guide you on the best sources of vitamin B12 and recommend supplements if needed.

What are the recommended dietary guidelines for Cobalamin (Vitamin B12) for individuals with celiac disease?

Individuals with celiac disease, an autoimmune disorder characterized by an intolerance to gluten (a protein found in wheat, barley, and rye), may face challenges in absorbing nutrients, including vitamin B12. Malabsorption issues are common in celiac disease due to damage to the small intestine’s lining.

The recommended dietary guidelines for vitamin B12 for individuals with celiac disease are similar to the general guidelines; however, it’s crucial for individuals with celiac disease to take extra steps to ensure adequate vitamin B12 intake and absorption:

  1. Ensure a Gluten-Free Diet:
    • Strict adherence to a gluten-free diet is the primary recommendation for individuals with celiac disease to manage the condition and improve nutrient absorption, including vitamin B12.
  2. Include B12-Rich Foods:
    • Incorporate vitamin B12-rich foods that are naturally gluten-free into your diet. These include meats, fish, poultry, eggs, dairy products, and fortified cereals.
  3. Consider Fortified Foods:
    • Include foods fortified with vitamin B12, such as certain breakfast cereals, plant-based milk alternatives (e.g., almond milk, soy milk) fortified with B12.
  4. Supplementation:
    • Depending on the severity of malabsorption and the individual’s specific needs, a healthcare professional may recommend vitamin B12 supplementation in the form of oral supplements, sublingual tablets, or injections to ensure adequate intake and absorption.
  5. Regular Monitoring:
    • Individuals with celiac disease should undergo regular monitoring of vitamin B12 levels through blood tests to assess whether dietary changes and supplementation are effectively addressing potential deficiencies.
  6. Consult a Dietitian:
    • Work with a registered dietitian or healthcare professional with expertise in celiac disease and nutrition to develop a personalized nutrition plan that ensures adequate vitamin B12 intake and other essential nutrients.

It’s important to note that celiac disease may also be associated with other nutritional deficiencies due to malabsorption, so a comprehensive approach to nutritional management is essential. Always consult with a healthcare professional or registered dietitian to tailor dietary recommendations to your specific needs and health circumstances.

What are the recommended dietary guidelines for Cobalamin (Vitamin B12) for individuals with food allergies?

Individuals with food allergies, particularly those who have allergies to foods that are common sources of vitamin B12 (such as dairy, eggs, and fish), need to carefully plan their diets to ensure they meet their vitamin B12 requirements. Here are some dietary guidelines for vitamin B12 for individuals with food allergies:

  1. Identify Alternative Sources:
    • If you have allergies to foods rich in vitamin B12 (e.g., dairy, eggs, fish), it’s essential to identify alternative sources of vitamin B12 in your diet. Lean towards non-allergenic sources such as fortified cereals, fortified plant-based milk (e.g., almond milk, soy milk), and vitamin B12 supplements.
  2. Fortified Foods:
    • Include fortified foods in your diet. Many plant-based milk alternatives, breakfast cereals, nutritional yeast, and plant-based meat substitutes are fortified with vitamin B12. Check labels to ensure the product is fortified with B12.
  3. Supplementation:
    • Depending on the severity of your allergies and your ability to consume fortified foods, vitamin B12 supplementation may be necessary. Consult a healthcare professional to determine the appropriate dosage and form of supplementation (e.g., oral supplements, sublingual tablets, injections).
  4. Regular Monitoring:
    • Regularly monitor your vitamin B12 levels through blood tests to ensure that your dietary choices and potential supplementation are effectively addressing any deficiencies.
  5. Consult a Dietitian:
    • Work with a registered dietitian or healthcare professional with expertise in food allergies and nutrition to develop a personalized nutrition plan that ensures adequate vitamin B12 intake and other essential nutrients.
  6. Explore Alternative Protein Sources:
    • Since vitamin B12 is often found in animal-based protein sources, consider exploring alternative protein sources suitable for your allergies, such as legumes, nuts, seeds, and plant-based protein products.

It’s crucial to manage your diet carefully to meet your vitamin B12 needs, especially if you have dietary restrictions due to food allergies. Always consult with a healthcare professional or registered dietitian for personalized guidance and to ensure you’re meeting your nutritional requirements while managing your allergies.

What symptoms and conditions are associated with Cobalamin (Vitamin B12) deficiency?

Vitamin B12 deficiency can manifest in various symptoms and may lead to a range of health conditions if left untreated. Common signs and symptoms of vitamin B12 deficiency include:

  1. Fatigue and Weakness:
    • Feeling tired and weak, even with adequate rest, is a common early symptom of vitamin B12 deficiency.
  2. Anemia:
    • Vitamin B12 deficiency can lead to a type of anemia known as megaloblastic anemia, where red blood cells are larger than normal and fewer in number, leading to reduced oxygen-carrying capacity in the blood.
  3. Pale or Jaundiced Skin:
    • A deficiency in vitamin B12 may cause a pale or jaundiced (yellowing) appearance of the skin due to the reduced production of red blood cells.
  4. Shortness of Breath and Dizziness:
    • Reduced oxygen-carrying capacity due to anemia can cause shortness of breath, dizziness, and difficulty breathing.
  5. Heart Palpitations and Chest Pain:
    • Anemia can cause an increased heart rate and irregular heartbeats, leading to heart palpitations and chest pain.
  6. Cognitive Impairment and Memory Problems:
    • Vitamin B12 deficiency can affect cognitive function, leading to memory problems, difficulty concentrating, and impaired thinking.
  7. Numbness and Tingling:
    • Deficiency can cause peripheral neuropathy, characterized by numbness, tingling, or a “pins and needles” sensation in the hands and feet.
  8. Difficulty Walking and Balance Issues:
    • Severe vitamin B12 deficiency can affect the nervous system, leading to difficulty walking, balance problems, and coordination issues.
  9. Mood Changes and Depression:
    • Some individuals with vitamin B12 deficiency may experience mood swings, depression, and irritability.
  10. Glossitis and Mouth Ulcers:
    • Deficiency can cause inflammation of the tongue (glossitis) and mouth ulcers.
  11. Vision Problems:
    • In severe cases, vitamin B12 deficiency can lead to vision disturbances and optic nerve damage.
  12. Digestive Issues:
    • Some individuals may experience digestive symptoms such as diarrhea, constipation, loss of appetite, and weight loss.
  13. Developmental Delays in Children:
    • Vitamin B12 deficiency in infants and young children can lead to developmental delays, failure to thrive, and impaired cognitive development.

It’s important to note that symptoms of vitamin B12 deficiency can develop gradually and may vary from person to person. If you suspect a deficiency or experience persistent symptoms, consult a healthcare professional for appropriate testing and guidance. Vitamin B12 deficiency is treatable with dietary changes, supplementation, or injections, depending on the severity of the deficiency.

Who’s at risk for Cobalamin (Vitamin B12) deficiency?

Several groups of people are at an increased risk of developing vitamin B12 deficiency due to various factors that may affect absorption, dietary intake, or utilization of this vitamin. Here are the key risk groups:

  1. Vegetarians and Vegans:
    • Vitamin B12 is primarily found in animal products. Individuals following a vegetarian or vegan diet may have a higher risk of vitamin B12 deficiency since plant-based foods do not naturally contain adequate amounts of this vitamin.
  2. Older Adults:
    • As people age, their ability to absorb vitamin B12 from food can decline. Older adults may have reduced stomach acid production, which is necessary for B12 absorption.
  3. Individuals with Gastrointestinal Disorders:
    • Conditions affecting the gastrointestinal tract, such as celiac disease, Crohn’s disease, atrophic gastritis, and pernicious anemia, can impair vitamin B12 absorption and increase the risk of deficiency.
  4. Pernicious Anemia Patients:
    • Pernicious anemia is an autoimmune condition where the body attacks cells in the stomach that produce intrinsic factor, a protein required for B12 absorption. People with pernicious anemia cannot absorb enough B12 naturally and require B12 supplementation.
  5. Individuals who’ve Undergone Gastrointestinal Surgery:
    • Surgical procedures involving the stomach or small intestine can affect vitamin B12 absorption. Those who have had gastric bypass surgery, gastrectomy, or ileal resection may have a higher risk of deficiency.
  6. Individuals with Atrophic Gastritis:
    • Atrophic gastritis is a condition characterized by the thinning of the stomach lining, which reduces the production of stomach acid and intrinsic factor, hindering B12 absorption.
  7. Long-Term Antacid or Proton Pump Inhibitor (PPI) Users:
    • Antacids and PPIs, which are often used to manage gastric reflux and ulcers, can decrease stomach acid production, affecting vitamin B12 absorption over time.
  8. Individuals with Autoimmune Conditions:
    • Certain autoimmune disorders, such as type 1 diabetes, lupus, and thyroid disorders, are associated with an increased risk of developing pernicious anemia and subsequent B12 deficiency.
  9. Alcoholics:
    • Chronic alcohol consumption can impair B12 absorption and increase the risk of vitamin B12 deficiency.
  10. Infants of Breastfeeding Vegetarian or Vegan Mothers:
    • Infants born to mothers following a strict vegetarian or vegan diet, especially those who are breastfeeding and not supplementing with vitamin B12, can be at risk of deficiency.
  11. Malabsorption Disorders:
    • Conditions that cause malabsorption, like pancreatic insufficiency or bacterial overgrowth in the small intestine, can reduce B12 absorption.

Regular monitoring of vitamin B12 levels, appropriate dietary adjustments, fortified foods, and supplementation (as advised by a healthcare professional) can help mitigate the risks associated with vitamin B12 deficiency. If you fall into any of these risk categories, consider discussing your vitamin B12 status and needs with a healthcare provider.

What is Cobalamin (Vitamin B12) toxicity?

Vitamin B12 toxicity, also known as hypervitaminosis B12, is a condition characterized by an excess of vitamin B12 in the body. Vitamin B12 is a water-soluble vitamin, which means that excess amounts are typically excreted in the urine and not stored in the body to the same extent as fat-soluble vitamins like vitamins A and D. As a result, vitamin B12 toxicity is rare and usually not a significant concern.

Potential Causes of Vitamin B12 Toxicity:

  1. Excessive Dietary Intake: Consuming very high doses of vitamin B12 supplements or fortified foods for an extended period.
  2. Medical Treatments: Intravenous (IV) or intramuscular (IM) injections of vitamin B12 in excessive amounts, particularly inappropriately high doses of B12 injections.
  3. Underlying Health Conditions: Certain health conditions, such as liver disease or kidney disorders, may disrupt the body’s ability to metabolize and excrete excess vitamin B12.
  4. Genetic Predisposition: Some individuals may have a genetic predisposition that affects their ability to metabolize vitamin B12, leading to accumulation.

Symptoms and Effects of Vitamin B12 Toxicity:

  • Vitamin B12 toxicity is rare and typically not associated with serious health effects. The body efficiently excretes excess vitamin B12 through urine.
  • High doses of vitamin B12 may cause minor symptoms such as itching, rash, diarrhea, and swelling.
  • There are no known reports of life-threatening effects resulting from excessive vitamin B12 intake.

Management and Prevention:

  • The best way to prevent vitamin B12 toxicity is to avoid excessive supplementation and high-dose injections without appropriate medical supervision.
  • Always follow recommended dosages and guidelines provided by healthcare professionals or the product’s labeling when taking vitamin B12 supplements or receiving injections.

It’s important to emphasize that vitamin B12 is considered safe for the vast majority of individuals when consumed within recommended levels. If you have concerns about your vitamin B12 intake, potential toxicity, or if you’re considering high-dose B12 supplementation, consult a healthcare professional for appropriate guidance and monitoring. They can assess your specific situation and recommend the right amount of vitamin B12 for your needs.

Are there any food or drug interactions with Cobalamin (Vitamin B12)?

Vitamin B12 is generally considered safe and does not typically interact with most foods. However, there are a few considerations regarding interactions with certain foods and drugs:

  1. Interactions with Medications:
    • Proton Pump Inhibitors (PPIs) and H2 Blockers: These medications, used to reduce stomach acid, can potentially decrease the absorption of vitamin B12 from food. If you are on long-term PPIs or H2 blockers, your healthcare provider may monitor your vitamin B12 levels and recommend supplementation if needed.
    • Metformin: Long-term use of the diabetes medication metformin can reduce vitamin B12 absorption. Regular monitoring of vitamin B12 levels and supplementation if necessary may be advised for individuals on long-term metformin therapy.
  2. Interactions with Other Supplements:
    • Folic Acid (Vitamin B9): High levels of folic acid can mask the symptoms of vitamin B12 deficiency, as both vitamins work together to produce red blood cells. It’s important to maintain an appropriate balance of both vitamins to avoid complications related to vitamin B12 deficiency.
  3. Interactions with Alcohol:
    • Chronic alcohol consumption can interfere with vitamin B12 absorption and increase the risk of vitamin B12 deficiency. It’s important to moderate alcohol intake and maintain a balanced diet.
  4. Iron and Calcium Supplements:
    • While iron and calcium supplements do not directly interact with vitamin B12, it’s important to space out the intake of these supplements if taken together. High doses of calcium or iron can interfere with vitamin B12 absorption when taken simultaneously.
  5. Caffeine:
    • High caffeine intake may interfere with vitamin B12 absorption. Moderation in caffeine consumption is advisable.
  6. Foods Rich in Vitamin B12:
    • There are no significant interactions with foods rich in vitamin B12. In fact, consuming vitamin B12-rich foods such as meats, fish, eggs, dairy products, and fortified cereals is essential for meeting your B12 needs.

Always consult with your healthcare provider or a registered dietitian if you have concerns about potential interactions between vitamin B12, medications, or specific foods. They can provide personalized advice based on your individual circumstances and health conditions. It’s important to maintain a balanced diet and inform your healthcare provider about any supplements or medications you are taking.


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  • Nutritional considerations on the gluten-free diet. [accessed 2023 Oct 6].
  • Steffens K. 2023 Feb 28. Methyl B12 for autism. The Autism Community in Action. [accessed 2023 Oct 6].
  • Taylor AK, Lebwohl B, Snyder CL, Green PHR. 2019. Celiac Disease. University of Washington, Seattle. [accessed 2023 Oct 6].


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Jamie with ZERO For Life

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My name is Jamie. My family and I know first hand what it's like to live with celiac disease and food allergies. Helping people like us with similar challenges take charge of their health and happiness is my undying passion. My focus is on providing you with both accurate health information that’s grounded in science and practical tools to help you successfully live a completely gluten free and/or allergen free lifestyle.

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