Introduction: The B12 Brilliance 🌟

Hold onto your hats, health enthusiasts! We're about to embark on a thrilling journey into the world of Vitamin B12 - the unsung hero of the vitamin kingdom. This nutrient might be tiny, but it packs a punch when it comes to your health, particularly your gut, brain, and immune system.

Picture B12 as the backstage manager of your body's Broadway show. While it may not be in the spotlight, without it, the whole performance could fall apart! From supporting your gut microbiome to keeping your brain sharp and your immune system in top form, B12 is the behind-the-scenes superstar making sure everything runs smoothly.

But here's the kicker - unlike some other nutrients, your body can't produce B12 on its own. It's like trying to run a show without a script - it just won't work! You need to get your B12 fix from food or supplements to keep your internal performance running smoothly.

Despite its crucial role, B12 deficiency is more common than you might think. About 6% of adults under 60 and 20% of adults over 60 in the U.S. are B12 deficient. That's like one in five older adults walking around with their internal Broadway show on the verge of cancellation!

So, are you ready to power up your health with B12? Strap in as we explore how this mighty vitamin could be the key to unlocking better gut-brain health, stronger immunity, and overall well-being. It's time to give B12 its well-deserved spotlight! 🎭

A Brief History: Discovering Vitamin B12

Buckle up, time travelers! We're about to take a whirlwind tour through the history of Vitamin B12. It's a tale of mystery, discovery, and Nobel Prize-winning breakthroughs! 🏆

  • 1824: The story begins with a description of pernicious anemia by James Combe. Little did he know, he was setting the stage for B12's grand entrance!

  • 1920s: Two doctors, George Whipple and George Minot, discover that feeding liver to anemic dogs could treat pernicious anemia. It's like they found a magical health potion!

  • 1934: Whipple, Minot, and William Murphy win the Nobel Prize in Physiology or Medicine for their liver therapy work. Talk about a liver-y celebration!

  • 1948: The plot thickens! American chemist Karl A. Folkers and British biochemist Alexander R. Todd independently isolate vitamin B12 as a pure crystal. It's the scientific equivalent of striking gold!

  • 1954: Dorothy Hodgkin determines the structure of B12 using X-ray crystallography, earning her the Nobel Prize in Chemistry in 1964. She's the Sherlock Holmes of the vitamin world!

  • 1972: Robert Woodward receives the Nobel Prize in Chemistry for his work on the synthesis of B12. It's like he cracked the code to recreate this vital nutrient!

  • 1990s-Present: Research continues to uncover new roles for B12, particularly in brain health, gut function, and immunity. The B12 saga is far from over!

Who knew a vitamin could have such a riveting backstory? But wait, there's more! Let's dive deeper into the B12 universe and discover why this tiny nutrient deserves a standing ovation. 👏

Vitamin B12 101: What You Need to Know

Alright, class, it's time for Vitamin B12 101! Don't worry, there won't be a pop quiz at the end (or will there? 😉). Let's break down the superpowers of this essential vitamin:

  1. Nerve Function Facilitator: B12 is like the electrician of your nervous system, ensuring all the wiring is in good shape. It's crucial for maintaining the myelin sheath that insulates nerve fibers. Without B12, your nervous system might short-circuit!

  2. DNA Synthesis Supporter: Think of B12 as the proofreader for your genetic code. It's essential for DNA synthesis and regulation. It's making sure your cellular instruction manual stays in tip-top shape!

  3. Red Blood Cell Producer: B12 is the factory foreman for your red blood cell production. Without enough B12, your body can't produce healthy red blood cells, leading to anemia. It's like trying to run a delivery service without enough trucks!

  4. Brain Function Booster: Your brain loves B12! It plays a crucial role in cognitive function and mood regulation. It's the personal trainer for your brain cells, keeping them fit and firing on all cylinders.

  5. Gut Health Guardian: B12 is a key player in maintaining a healthy gut. It supports the gut lining and influences the balance of bacteria in your gut microbiome. Think of it as the bouncer for your gut-brain axis, keeping things running smoothly in your internal communication network.

  6. Immune System Supporter: B12 is like a drill sergeant for your immune cells, helping them develop and function properly. It's crucial for a strong immune system.

  7. Energy Metabolism Maven: Feeling sluggish? B12 might be the answer! It plays a key role in energy metabolism, helping to convert the food you eat into energy your cells can use. It's like the fuel injector for your cellular engines!

Fun Fact: Vitamin B12 is the largest and most structurally complex vitamin. It's like the elephant in the vitamin room! 🐘

Understanding these basic functions is key to appreciating why B12 is so crucial for our overall health. As we delve deeper into its roles and benefits, you'll see just how this unassuming vitamin packs such a powerful punch in maintaining our well-being. Stay tuned, B12 enthusiasts! 🎬

How Vitamin B12 Works in Your Body

Get ready for a wild ride through the B12-verse! This vitamin might be complex, but its effects are nothing short of miraculous. Let's break down B12's busy day in your body:

  1. The Great Absorption Adventure 🌪️

    B12's journey in your body is like an epic quest:

    • It starts in your mouth, where it binds to a protein called haptocorrin.
    • In your stomach, hydrochloric acid and pepsin free B12 from food proteins.
    • B12 then binds to intrinsic factor, produced by stomach cells.
    • This B12-intrinsic factor complex travels to the small intestine.
    • Finally, it's absorbed in the ileum (last part of the small intestine).

    It's like a molecular version of "The Lord of the Rings" - a long journey with a crucial mission!

  2. The Methylation Master 🧬

    B12 is a key player in methylation, a process crucial for:

    • DNA synthesis and repair
    • Neurotransmitter production
    • Detoxification
    • Gene expression regulation

    Think of B12 as the conductor of a complex biochemical orchestra, ensuring every instrument plays in harmony.

  3. The Nerve Nurturer 🧠

    B12 is essential for maintaining healthy nerves:

    • It helps form the myelin sheath around nerves.
    • Supports the production of neurotransmitters.
    • Aids in nerve regeneration.

    Without B12, your nervous system would be like a computer with frayed wires!

  4. The Blood Cell Builder 🩸

    B12 is crucial for healthy red blood cell formation:

    • It works with folate to produce DNA in red blood cells.
    • Helps red blood cells mature properly.
    • Prevents megaloblastic anemia.

    B12 is like the foreman at the red blood cell factory, ensuring quality production!

  5. The Gut Guardian 🦠

    B12 plays a role in maintaining gut health:

    • Supports the integrity of the gut lining.
    • Influences the balance of gut bacteria.
    • May help prevent inflammation in the gut.

    It's like having a skilled maintenance crew for your gut, similar to how zinc supports gut health.

  6. The Immune System Ally 🛡️

    B12 supports your immune system by:

    • Enhancing the production and function of immune cells.
    • Supporting the development of natural killer cells.
    • Aiding in the production of antibodies.

    B12 is like the drill sergeant for your immune army, keeping your defenses strong!

  7. The Energy Enhancer ⚡

    B12 is key in energy production:

    • It's involved in the metabolism of fats and proteins.
    • Helps convert carbohydrates into glucose.
    • Supports the citric acid cycle (a key energy-producing process).

    Without B12, you'd feel like a smartphone with a dying battery!

Did You Know? B12 is the only vitamin containing a trace element (cobalt). It's like having a mini-mineral as part of your vitamin! 🔬

As you can see, B12 is the ultimate multitasker in your body. It's like the Swiss Army knife of vitamins - always ready with the right tool for the job. So next time you're chowing down on some B12-rich foods or taking your supplement, give a little nod of appreciation to this hardworking vitamin. Your body certainly does! 🙌

Food Sources and Supplements: Getting Your B12

Alright, B12 seekers, it's time to talk about how to invite more of this vital vitamin into your life. Whether you're a meat lover, a vegetarian, or somewhere in between, there's a B12 source with your name on it!

Food Sources

  1. Animal Sources (naturally high in B12):

    • Liver (beef liver, 3 oz): 70.7 μg (2,944% of Daily Value) - The undisputed B12 champion!
    • Clams (3 oz): 84.1 μg (3,504% of DV) - Who knew these little shellfish were B12 powerhouses?
    • Sardines (3 oz): 6.6 μg (275% of DV) - Small fish, big B12 impact!
    • Beef (3 oz): 1.5 μg (62% of DV) - A beefy dose of B12
    • Tuna (3 oz): 2.5 μg (104% of DV) - Swimming in B12 goodness
    • Salmon (3 oz): 4.9 μg (204% of DV) - A splash of B12
    • Eggs (1 large): 0.6 μg (25% of DV) - Every little bit helps!

  2. Fortified Foods (great for vegetarians and vegans):

    • Nutritional yeast (1/4 cup): 17.6 μg (733% of DV) - A vegan's B12 best friend!
    • Plant-based milk (1 cup): 0.7-1.2 μg (29-50% of DV) - Depends on brand
    • Fortified cereals (1 cup): 0.6-6.0 μg (25-250% of DV) - B12 for breakfast!

Now, here's a fun fact: B12 from animal sources is generally more bioavailable than that from plant sources or supplements. It's like getting a first-class ticket on the B12 express! 🚂

B12 Supplements

If you're not getting enough B12 from your diet, or if you have increased needs, supplements can be a great option. Here are some common types:

  1. Cyanocobalamin: The most common and least expensive form.
  2. Methylcobalamin: A more active form, often preferred by alternative health practitioners.
  3. Hydroxocobalamin: Lasts longer in the body, often used for B12 injections.
  4. Adenosylcobalamin: Another active form, less commonly available as a supplement.

The recommended dietary allowance (RDA) for B12 is:

  • Adults (14+ years): 2.4 μg/day
  • Pregnant women: 2.6 μg/day
  • Breastfeeding women: 2.8 μg/day

However, many experts recommend higher doses, especially for older adults or those with absorption issues. It's like a B12 prescription - one size doesn't fit all! 📏

Always consult a healthcare provider before starting supplements, as excessive B12 intake is generally not a concern, but it's best to ensure you're taking the right form and dose for your needs.

Remember, when it comes to B12, more is often better, especially if you're in a high-risk group for deficiency. Aim to meet your needs through a balanced diet first, and consider supplements if recommended by your healthcare provider. After all, you want to be a B12 enthusiast, not a B12 underachiever! 🏆

Health Benefits: Why B12 Matters

Buckle up, folks! We're about to take a thrilling ride through the health benefits of Vitamin B12. This vitamin might be complex, but its impact on your health is crystal clear!

  1. Brain Health Booster 🧠

    • Supports cognitive function and memory
    • May help prevent brain atrophy and cognitive decline
    • Plays a role in mood regulation and may help alleviate depression

    A study published in the American Journal of Clinical Nutrition found that older adults with higher B12 levels had a lower risk of brain shrinkage and cognitive decline.

  2. Nervous System Nurturer 🔌

    • Essential for maintaining healthy nerves
    • Helps prevent peripheral neuropathy
    • Supports overall neurological function

    B12 is crucial for the formation of myelin, the protective coating around nerves. Without it, it's like trying to use electrical wires without insulation!

  3. Energy Enhancer ⚡

    • Plays a key role in energy metabolism
    • Helps convert food into glucose
    • May help reduce fatigue and weakness

    Feeling sluggish? B12 might be the answer! It's like having a personal energy manager in your cells.

  4. Heart Health Helper ❤️

    • Helps regulate homocysteine levels
    • May reduce the risk of heart disease and stroke
    • Supports overall cardiovascular health

    B12, along with folate and B6, helps keep homocysteine levels in check. High homocysteine is linked to increased heart disease risk.

  5. Anemia Annihilator 🩸

    • Essential for red blood cell formation
    • Prevents megaloblastic anemia
    • Supports overall blood health

    Without B12, your body can't produce healthy red blood cells. It's like trying to run a delivery service without enough trucks!

  6. Gut Health Guardian 🦠

    • Supports the health of the gut lining
    • May influence the gut microbiome
    • Helps maintain overall digestive health

    B12 plays a role in maintaining the integrity of your gut lining, similar to how Vitamin D supports gut barrier function.

  7. Immune System Supporter 🛡️

    • Enhances immune cell production and function
    • Supports the development of natural killer cells
    • Aids in antibody production

    B12 is like a personal trainer for your immune system, keeping it in fighting shape!

  8. Skin, Hair, and Nail Nourisher 💅

    • Supports healthy cell production
    • May help improve skin, hair, and nail health
    • Could potentially help with certain skin conditions

    Want that healthy glow? B12 might be your beauty secret!

  9. Fertility Friend 👶

    • Important for healthy sperm production
    • Crucial for fetal development during pregnancy
    • May help prevent birth defects

    Planning for a baby? Make sure your B12 levels are up to par!

  10. Bone Health Buddy 🦴

    • Plays a role in maintaining bone health
    • May help prevent osteoporosis
    • Works synergistically with other bone-supporting nutrients

    B12 works alongside other nutrients like Vitamin K2 to keep your bones strong.

From boosting your brain power to keeping your energy levels high, B12 is truly a jack-of-all-trades in the vitamin world. It's like having a Swiss Army knife for your health - always ready with the right tool for the job!

Remember, these benefits are most pronounced when you're getting adequate B12. If you're deficient, addressing that deficiency can lead to significant improvements in many areas of health. It's like giving your body the missing piece of a complex puzzle!

So, next time you're enjoying a B12-rich meal or taking your supplement, give a little cheer for this mighty vitamin. Your body is certainly thankful for it! 🎉

Signs of Deficiency: Are You Getting Enough?

Alright, detectives, it's time to put on your sleuthing hats! We're about to uncover the mystery of B12 deficiency. Like any good detective story, we need to look for the clues. In this case, the clues are the symptoms your body might be showing if it's not getting enough of this vital vitamin.

Common symptoms of B12 deficiency include:

  • Fatigue and weakness 😴: If you're feeling more tired than a sloth on a lazy Sunday, B12 deficiency might be to blame. B12 is crucial for energy production, so low levels can leave you feeling exhausted.

  • Pale or jaundiced skin 👻: Looking a bit ghostly? B12 deficiency can lead to a type of anemia that makes you pale or gives your skin a yellowish tinge.

  • Pins and needles sensation �pins: That tingling feeling in your hands and feet might not be your limbs falling asleep - it could be B12 deficiency affecting your nerves.

  • Changes in mobility 🚶‍♂️: Difficulty walking, balance problems, or changes in the way you move could be signs of B12 deficiency affecting your nervous system.

  • Glossitis (inflamed tongue) 👅: If your tongue is swollen, red, or painful, it might be trying to tell you it needs more B12!

  • Breathlessness and dizziness 🌀: Feeling winded after minimal exertion? B12 deficiency anemia might be making it hard for your body to transport oxygen effectively.

  • Mood changes 😔: Feeling down or anxious for no apparent reason? B12 plays a role in producing brain chemicals that affect mood.

  • Vision changes 👁️: Blurry or disturbed vision can be a symptom of severe B12 deficiency.

  • Cognitive difficulties 🧠: Trouble with memory, understanding, and judgment can be signs of B12 deficiency, especially in older adults.

But wait, there's more! Certain factors can put you at higher risk of B12 deficiency:

  • Strict vegetarian or vegan diets (plants don't naturally contain B12)
  • Age over 50 (ability to absorb B12 from food decreases with age)
  • Gastrointestinal disorders like Crohn's disease or celiac disease
  • Weight loss surgery
  • Long-term use of certain medications (like metformin for diabetes or proton pump inhibitors for acid reflux)
  • Excessive alcohol consumption
  • Pernicious anemia (an autoimmune condition affecting B12 absorption)

Remember, if you suspect you're the star of "CSI: B12 Deficiency," don't try to solve the case alone. Consult with a healthcare professional for proper evaluation and advice. They're like the Sherlock Holmes of nutrition, ready to solve your B12 mystery! 🕵️‍♀️

Early detection and treatment of B12 deficiency is crucial. Unlike some other vitamins, B12 deficiency can lead to permanent nerve damage if left untreated for too long. It's like letting a small leak in your roof go unrepaired - eventually, it could lead to major damage!

So, stay vigilant, B12 sleuths. Your body will thank you for it! 🙏

B12 and Other Nutrients: Better Together

Alright, nutrient enthusiasts, it's time to talk about B12's friend group! Just like how you're more fun at a party with your best pals, B12 works better when it's hanging out with certain other nutrients. Let's explore these nutritional friendships (and a few rivalries):

B12 works synergistically with:

  1. Folate (Vitamin B9) 🤝

    • These two are like the dynamic duo of DNA synthesis and red blood cell production.
    • They work together to lower homocysteine levels, potentially reducing heart disease risk.
    • B12 helps convert folate into its active form in the body.

  2. Iron 🦸‍♀️

    • B12 and iron are like the power couple of blood health.
    • They work together in red blood cell production.
    • B12 helps your body utilize iron more effectively.

    Want to know more about iron's superpowers? Check out our deep dive into iron's role in gut health and immunity.

  3. Vitamin C 🍊

    • While not directly involved in B12 absorption, Vitamin C can enhance the absorption of iron, which works alongside B12.
    • It's like Vitamin C is holding the door open for iron, which in turn helps B12 do its job better.

    Curious about Vitamin C's other talents? Take a look at our article on the benefits of liposomal Vitamin C.

  4. Vitamin B6 🤹‍♀️

    • B6, B12, and folate form a trio that works together in many biochemical reactions.
    • They're particularly important in homocysteine metabolism and neurotransmitter production.

    For more on the B vitamin family's impressive repertoire, check out our post on the role of B vitamins in digestive health and immunity.

  5. Magnesium 🧲

    • Magnesium is involved in the activation of B vitamins, including B12.
    • It's like magnesium is the key that unlocks B12's potential.

However, B12 can also have some nutrient interactions to be aware of:

  1. Potassium ⚠️

    • High doses of potassium supplements can reduce B12 absorption.
    • It's like potassium is accidentally blocking B12's entrance.

  2. Vitamin C (in high doses) 🚧

    • While usually helpful, very high doses of Vitamin C can degrade B12 in the digestive tract.
    • It's a reminder that even good things can be problematic in excess!

  3. Calcium 🥛

    • Calcium supplements might interfere with B12 absorption if taken at the same time.
    • It's best to space out calcium supplements and B12-rich meals or supplements.

Understanding these interactions can help you optimize your nutrient intake and avoid potential imbalances. It's like being the peacekeeper at a nutrient party - making sure everyone gets along and has a good time!

Remember, a balanced diet typically provides the right mix of nutrients, but if you're considering supplements, it's best to consult with a healthcare professional. They're like the party planners of the nutrient world, ensuring everyone plays nice and you get the most out of your nutritional fiesta! 🎉

Conclusion: Embracing B12 for Better Health

And there you have it, folks! We've journeyed through the B12 universe, from its Nobel Prize-winning discovery to its starring role in your health. Who knew such a complex vitamin could pack such a powerful punch?

Let's recap our B12 adventure:

  1. B12 is an essential vitamin that's crucial for numerous bodily functions, from supporting your brain health to ensuring your energy levels stay high.

  2. It plays a vital role in maintaining your gut health, supporting your nervous system, and keeping your immune system in fighting shape.

  3. You can get your B12 fix from a variety of animal foods, from liver (the B12 superstar) to eggs, and from fortified foods for our plant-based friends.

  4. B12 deficiency can lead to a host of issues, from fatigue to nerve damage. It's like your body's way of waving a red flag!

  5. B12 works best when it's part of a balanced nutrient team. It's got some best buds (like folate) and some potential rivals (looking at you, high-dose Vitamin C).

  6. While B12 toxicity is rare, it's still important to get the right amount for your needs. More isn't always better, but in the case of B12, it often is!

Remember, B12 is just one piece of the nutritional puzzle. A balanced diet rich in a variety of nutrients is key to optimal health. It's like assembling a superhero team - each nutrient has its own superpower, but they work best together!

As research continues to uncover new roles for this essential vitamin, one thing is clear: B12 is a true unsung hero in the world of nutrition. So next time you're chowing down on some B12-rich foods or taking your supplement, give a little nod of appreciation to this mighty vitamin.

Here's to your health, powered by the marvel that is B12! May your nerves be protected, your energy be high, and your B12 levels be optimal. Now go forth and spread the gospel of B12 - your body will thank you! 🎉💪🧠

Further Reading

  1. "Could It Be B12?: An Epidemic of Misdiagnoses" by Sally M. Pacholok and Jeffrey J. Stuart

  2. "Vitamin B12 Deficiency in Clinical Practice" by Martin Koury and Joseph Ponka

  3. "The Cobalamin Deficiency State" by Robert C. Oh and David L. Brown

  4. "Vitamin B12: Advances and Insights" by Rima Obeid

  5. "The Vitamin B12 Solution: Your Ultimate Guide to Preventing and Reversing B12 Deficiency" by Cliff Bacchus

  6. "Methylation: The Vital Link to Health" by Richard A. Kunin

  7. "The Methylation Miracle: Unleashing Your Body's Natural Source of SAM-e" by Paul Frankel

  8. "The Paleo Cardiologist: The Natural Way to Heart Health" by Jack Wolfson (includes information on B12 and heart health)

  9. "Brain Maker: The Power of Gut Microbes to Heal and Protect Your Brain–for Life" by David Perlmutter (discusses the role of B12 in brain health)

  10. "Why Isn't My Brain Working?: A Revolutionary Understanding of Brain Decline and Effective Strategies to Recover Your Brain's Health" by Datis Kharrazian

References

  1. Green, R., Allen, L. H., Bjørke-Monsen, A. L., Brito, A., Guéant, J. L., Miller, J. W., ... & Yajnik, C. (2017). Vitamin B12 deficiency. Nature Reviews Disease Primers, 3(1), 1-20. https://www.nature.com/articles/nrdp201740

  2. O'Leary, F., & Samman, S. (2010). Vitamin B12 in health and disease. Nutrients, 2(3), 299-316. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257642/

  3. Langan, R. C., & Goodbred, A. J. (2017). Vitamin B12 deficiency: recognition and management. American Family Physician, 96(6), 384-389. https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html

  4. Azevedo, F. R., Barbosa, M. C., & Lisboa, P. C. (2018). Vitamin B12 deficiency: understanding its impact on health. Revista da Associação Médica Brasileira, 64, 494-503. https://www.scielo.br/j/ramb/a/PJWMBCYFsKHCWN6JnqgXt3c/?lang=en

  5. Lachner, C., Steinle, N. I., & Regenold, W. T. (2012). The neuropsychiatry of vitamin B12 deficiency in elderly patients. The Journal of Neuropsychiatry and Clinical Neurosciences, 24(1), 5-15. https://neuro.psychiatryonline.org/doi/full/10.1176/appi.neuropsych.11020052

  6. Rizzo, G., Laganà, A. S., Rapisarda, A. M., La Ferrera, G. M., Buscema, M., Rossetti, P., ... & Vitale, S. G. (2016). Vitamin B12 among vegetarians: status, assessment and supplementation. Nutrients, 8(12), 767. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5188422/

  7. Watanabe, F., Yabuta, Y., Bito, T., & Teng, F. (2014). Vitamin B12-containing plant food sources for vegetarians. Nutrients, 6(5), 1861-1873. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4042564/

  8. Wolffenbuttel, B. H., Wouters, H. J., Heiner-Fokkema, M. R., & van der Klauw, M. M. (2020). The many faces of cobalamin (vitamin B12) deficiency. Mayo Clinic Proceedings: Innovations, Quality & Outcomes, 4(6), 611-624. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7688056/

  9. Hunt, A., Harrington, D., & Robinson, S. (2014). Vitamin B12 deficiency. BMJ, 349, g5226. https://www.bmj.com/content/349/bmj.g5226

  10. Ankar, A., & Kumar, A. (2021). Vitamin B12 Deficiency. In StatPearls [Internet]. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK441923/

  11. Obeid, R., Fedosov, S. N., & Nexo, E. (2015). Cobalamin coenzyme forms are not likely to be superior to cyano-and hydroxyl-cobalamin in prevention or treatment of cobalamin deficiency. Molecular Nutrition & Food Research, 59(7), 1364-1372. https://onlinelibrary.wiley.com/doi/full/10.1002/mnfr.201500019

  12. Brito, A., Grap, S., Fedosov, S. N., Morales, S., Campos, C., & Allen, L. H. (2018). Vitamin B12 and cognitive function: an evidence-based analysis. Nutrients, 10(12), 1923. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6316490/

  13. Spence, J. D. (2016). Metabolic vitamin B12 deficiency: a missed opportunity to prevent dementia and stroke. Nutrition Research, 36(2), 109-116. https://www.sciencedirect.com/science/article/pii/S0271531715002985

  14. Manzanares, W., & Hardy, G. (2010). Vitamin B12: the forgotten micronutrient for critical care. Current Opinion in Clinical Nutrition & Metabolic Care, 13(6), 662-668. https://journals.lww.com/co-clinicalnutrition/Abstract/2010/11000/Vitamin_B12__the_forgotten_micronutrient_for.10.aspx

  15. Kozyraki, R., & Cases, O. (2013). Vitamin B12 absorption: mammalian physiology and acquired and inherited disorders. Biochimie, 95(5), 1002-1007. https://www.sciencedirect.com/science/article/pii/S0300908413000060

  16. Carmel, R. (2011). Biomarkers of cobalamin (vitamin B-12) status in the epidemiologic setting: a critical overview of context, applications, and performance characteristics of cobalamin, methylmalonic acid, and holotranscobalamin II. The American Journal of Clinical Nutrition, 94(1), 348S-358S. https://academic.oup.com/ajcn/article/94/1/348S/4597814

  17. Stabler, S. P. (2013). Vitamin B12 deficiency. New England Journal of Medicine, 368(2), 149-160. https://www.nejm.org/doi/full/10.1056/nejmcp1113996

  18. Allen, L. H. (2009). How common is vitamin B-12 deficiency?. The American Journal of Clinical Nutrition, 89(2), 693S-696S. https://academic.oup.com/ajcn/article/89/2/693S/4596795

  19. Andres, E., Loukili, N. H., Noel, E., Kaltenbach, G., Abdelgheni, M. B., Perrin, A. E., ... & Blickle, J. F. (2004). Vitamin B12 (cobalamin) deficiency in elderly patients. Canadian Medical Association Journal, 171(3), 251-259. https://www.cmaj.ca/content/171/3/251.short

  20. Pawlak, R., Parrott, S. J., Raj, S., Cullum-Dugan, D., & Lucus, D. (2013). How prevalent is vitamin B12 deficiency among vegetarians?. Nutrition Reviews, 71(2), 110-117. https://academic.oup.com/nutritionreviews/article/71/2/110/1940320