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Have you decided to follow a vegan diet? Do you prefer to stay away from milk, eggs, meat, and fish? This is the guide for you. Vitamin B12 is an essential nutrient for human wellbeing, and is found in animal products. When we don't consume the required amounts, we put ourselves at risk for a wide range of diseases.

If you're vegan, vegetarian, or avoid eating animal products for any other reason, we suggest you give this article a close look. We'll be discussing the importance of vitamin B12, what to eat to prevent B12 deficiency, and how to include vitamin-fortified vegan foods or supplements if you don't consume this nutrient naturally. Are you ready to learn?




Key Facts

  • Vitamin B12 is found near exclusively in animal products (meat, fish, eggs, and dairy).
  • Those of us who don't eat animal products must rely on foods fortified with added vitamin B12, or on supplements. Some people may suffer from B12 deficiency even if they have an omnivorous diet: older adults, people with chronic illnesses, or people on certain medications.
  • Those who prefer to follow a vegan diet can tend to their B12 levels with fortified foods. It's also important to evaluate whether you need to take supplements, and to avoid common myths and "fake news" about this vitamin. Medical oversight is essential for vegan children, pregnant women, and elderly adults.

Vitamin B12 Supplements: Our Selection

Some people's bodies are incapable of making full use of the vitamin B12 in food. This situation can affect both omnivores and vegans who eat food artificially fortified with B12. If you've been advised to complement your diet with a vitamin B12 supplement, why don't you give one of these curated products a try?

Buyer's Guide to Vitamin B12: What You Need to Know

Vitamin B12 is a nutrient found near exclusively in the animal products we eat. Algae, fungi, and other products like tempeh (fermented soybeans) have not been shown to provide this vitamin. As such, vegans must rely on vitamin-fortified food, or vitamin supplements, if we don't want to deal with hypovitaminosis.

b12

Some vegan products are artificially fortified with vitamin B12. (Source: Subbotina: 42149709/ 123rf.com)

Why Is It Important to Include B12 Foods in My Diet?

Vitamin B12, also called cobalamin, is involved in cells' DNA creation - the process used to create genetic material. It's also crucial for forming proteins, fats, and other vital molecules used to keep the body functioning. These include neurotransmitters and creatine (1).

Our own bodies cannot synthesize vitamin B12, so it must be obtained from the food we eat. Luckily, cobalamin has some of the lowest required dietary intake of any nutrient. Its daily reference intake for adults is 2 micrograms (ɥg). In other words, only 0.002 milligrams (2)!

Vitamin b12

Vitamin B12 is essential for life. (Source: Grechaniuk: 121418798/ 123rf.com)

What Are the Risks of Not Eating Foods with B12?

Did you know that vitamin B12 stays stored in your body? Fortunately, the human body is able to "amass" this nutrient and store it in the liver. This allows you to go months or years without eating B12 before your reserves are fully depleted. However, once you run out of cobalamin, the consequences of B12 deficiency are severe and unpleasant (6, 7):

  • Anemia. When your cobalamin reserves run out, you won't be able to create new red blood cells (the cells in charge of transporting oxygen). The red blood cells which remain end up large and deformed. In other words, the result is megaloblastic anemia ("mega" meaning large and "blastic" meaning the cell is immature). Symptoms include fatigue, unhealthily pale skin, and in severe cases, jaundice (yellowed skin).
  • Dementia. Vitamin B12 deficiency may affect your myelin, a substance which covers nerves and allows your brain to transmit signals to the rest of the body. The consequence of low vitamin B12, therefore, may be loss of sensation, balance problems, and in severe cases, dementia.
  • Heart Disease. Some studies have found a relationship between insufficient vitamin B12 levels and the development of cardiovascular problems and heart disease. These results, however, require validation by further study.
  • Problem Pregnancies. Vitamin B12, like folic acid, is an extremely critical nutrient for the health of a growing fetus. B12 deficiency could increase the risk of birth defects and disabilities like spina bifida (defects in spinal column and spinal cord formation).

Some experts are concerned by the possibility that suboptimal B12 levels could also lead to "overall weakened" health. In other words, low B12 reserves could affect your health overall and increase your odds of eyesight problems, weakened memory, and even osteoporosis. This problem would primarily affect older people (8).

Could I Develop B12 Deficiency Even If I Include It in My Diet?

So your diet includes animal products or vegan foods fortified with vitamin B12. You avoid overcooking and microwaving food when you can. Your meals are healthy and balanced. In spite of these lifestyle adjustments, is it still possible for you to end up with a cobalamin deficiency? We regret to inform you that you can. If you belong to any of these groups, be extra careful (8)!

  • Older Adults: The passage of time may make your digestive tract start to have trouble digesting food. This can interfere in your body's ability to absorb vitamin B12.
  • Digestive Tract Conditions: People with Crohn's disease or ulcerative colitis, people who have undergone surgery which removed part of their digestive tract, and people with serious bacterial or parasitic infections can all have problems absorbing this vitamin.
  • Pernicious Anemia: To be absorbed by the body, vitamin B12 must link up with a gastric receptor called "intrinsic factor". Your body can misidentify that receptor as foreign and destroy it if you suffer from pernicious anemia, an autoimmune disease. As a consequence, cobalamin deficiency ensues (9).
  • People on Medications: Some pharmaceutical drugs can interfere with vitamin B12 absorption. Metformin, for example, is a very popular anti-diabetic drug used to control blood sugar. It's been linked to possible cobalamin deficiency (10). Antibiotics, HIV treatments, and methotrexate could also lead to low B12.
  • Other Conditions: Thyroid problems and heart disease, among other conditions, have been linked to insufficient vitamin B12 levels.

If you're an older adult or have health problems, have no fear! Make an appointment with your doctor to discuss the need for an analysis, which will check if your B12 levels are below normal range.

Julio BasultoDietician-Nutritionist
"Eating solely plant-based food (also excluding dairy and eggs), as vegans do, will lead to a vitamin B12 deficiency."

Vegans and Vitamin B12: Our Advice

Those of us who follow the "compassionate diet" - vegans - may be at risk for a B12 deficiency. Vegetarians can also have low levels of this nutrient if they limit their consumption of milk and eggs (11). If that applies to you, there's no need to panic! The advice in this guide will help you prevent B12 deficiency in your plant-based diet.

Eat Fortified Food

If you've struck animal products from your diet, your B12 reserves stop replenishing themselves. After about three years (it may be earlier or later, depending on your starting levels of cobalamin), you could begin to suffer from B12 deficiency's dangerous consequences (12). You can, however, prevent that unpleasant outcome by watching your diet.

Some foods, like plant-based "milks", juice, and cereal, are fortified with added B12. They can help you ingest the cobalamin you need to stay healthy. Thankfully, the B12 in these products is cyanocobalamin, which is derived synthetically (13). As such, you can safely consider these foods cruelty-free.

Vitamin b12 in food

In nature, vitamin B12 is found in animal products.  (Source: Baibakova: 53650159/ 123rf.com)

Evaluate the Need to Take Supplements

Some studies call into question the actual effectiveness of fortified food. In these scientific articles, experts mistrust these products because they don't allow you to know the exact amount of vitamin B12 you're ingesting. Plus, if you're older or you have chronic health conditions, the cyanocobalamin in these foods may not end up being absorbed (14).

We suggest that, on top of eating fortified food, you ask your doctor whether you need to add a vitamin B12 supplement to your diet. If you have problems absorbing it, your doctor will prescribe "megadoses" of B12 taken orally or as injections. If you absorb it normally, your doctor may suggest you follow a supplement guideline like these (15):

  • At least 10 micrograms of B12 taken once a day
  • 2,000 micrograms de B12 taken once a week
Though B12 supplements are considered safe even at high doses, they can cause indigestion and drug interactions with your other medications. Ask your doctor how to prevent these problems, and do not exceed 5,000 micrograms of B12 a week.

Watch Out for False Promises

You may have heard certain myths and rumors about vitamin B12. For example, someone may have explained that you can get enough cobalamin by eating organic vegetables grown without pesticide, or even vegetables with a healthy bit of dirt! What truth is there to this kind of claim?

  • Are the bacteria on unwashed vegetables able to produce vitamin B12? Sadly, the bacteria on unwashed food produce only minimal amounts of cyanocobalamin. The chances of indigestion or an infection, however? Substantially higher. We don't suggest you try this "natural" method (16).
  • Does a raw vegan diet (not cooking vegetables) provide B12? Vegetables have not been shown to provide more cobalamin when eaten raw. Remember that this vitamin is found in animal products, not in plants (16).
  • Are spirulina and other algae (like nori and chlorella) high in B12? Algae contain a variety of cobalamin which is not very useful for human bodies. Their "pseudo-vitamin B12" has very low bioavailability, meaning our bodies have very little ability to absorb and activate it. As such, it is not considered a useful way to meet required B12 intake (17, 18).
  • Do buckwheat, shiitake mushrooms, tempeh, and tofu contain B12? Presently, no one has been able to show that these foods contain vitamin B12 in their natural state. They can, however, provide this nutrient if they've been fortified with added cyanocobalamin (15).

Mujer organizando sus comidas

Ask your doctor how to prevent B12 deficiency in children, pregnant women, and elderly adults.
(Source: Kachmar: 115514561/ 123rf.com)

Protect Vulnerable People

Vitamin B12 deficiency can have especially serious health consequences for children, pregnant women, and older adults. Little ones can develop serious neurological problems as a result of this deficiency. Future mothers may put their pregnancy at risk, and aging adults could suffer dementia or eyesight problems (19, 20, 21).

Contact a doctor or nutritionist before putting your children on a vegan diet. Vegan pregnant women should work with a specialist who can provide the necessary information and supplements. Older people should also ask a doctor what steps to follow if they opt for a cruelty-free diet.

Summary

Vitamin B12 is an essential nutrient to keep your body in good shape. Your brain and red blood cells thank you when you include this molecule in your diet. Unfortunately, because it is found exclusively in animal products, vegans may eventually develop B12 deficiency.

Those of us who follow plant-based diets can introduce food fortified with artificial forms of B12. However, some experts recommend being much more thorough. Taking regular vitamin supplements and checking in with your doctor periodically may be a safer option for at-risk groups. What about you? Do you include B12 in your diet, or do you instead rely on supplements?

If this guide helped you discover more about vitamin B12 and your diet, feel free to leave a comment and share this article.

(Featured image source: Elena: 74297734/ 123rf.com)

References (21)

1. Brito A, Hertrampf E, Olivares M, Gaitán D, Sánchez H, Allen LH, et al. Folatos y vitamina B12 en la salud humana. Rev Med Chil [Internet]. 2012 Nov ;140(11):1464–75.
Source

2. FESNAD. Ingestas Dietéticas de Referencia (IDR) para la Población Española, 2010. Act Dietética [Internet]. 2010 Oct;14(4):196–7.
Source

3. Foods highest in Vitamin B12 [Internet].
Source

4. Bennink Mr, Ono K. Vitamin B12, E and D Content of Raw and Cooked Beef. J Food Sci [Internet]. 1982 ;47(6):1786–92.
Source

5. Czerwonka M, Szterk A, Waszkiewicz-Robak B. Vitamin B12 content in raw and cooked beef. Meat Sci [Internet]. 2014 ;96(3):1371–5.
Source

6. Ankar A, Bhimji SS. Vitamin B12 Deficiency (Cobalamin) [Internet]. StatPearls. StatPearls Publishing; 2018 .
Source

7. González-Tarrío L, Fontana M, Romero J. Degeneración combinada subaguda medular, una complicación infrecuente de un problema frecuente en la práctica clínica: El déficit de vitamina B12. Semergen [Internet]. 2008 Oct 1 ;34(8):417–9.
Source

8. O’Leary F, Samman S. Vitamin B12 in Health and Disease. Nutrients [Internet]. 2010 Mar 5 ;2(3):299–316.
Source

9. Formoso Fernando, Orosa Elvira CA. Guía clínica de Anemia perniciosa [Internet]. Elsevier. 2013 .
Source

10. Aroda VR, Edelstein SL, Goldberg RB, Knowler WC, Marcovina SM, Orchard TJ, et al. Long-term metformin use and vitamin B12 deficiency in the diabetes prevention program outcomes study. J Clin Endocrinol Metab [Internet]. 2016 ;101(4):1754–61.
Source

11. Pawlak R, Parrott SJ, Raj S, Cullum-Dugan D, Lucus D. How prevalent is vitamin B12 deficiency among vegetarians? [Internet]. Vol. 71, Nutrition Reviews. 2013 . p. 110–7.
Source

12. Vitamin B12 Deficiency – Disorders of Nutrition – MSD Manual Consumer Version [Internet].
Source

13. Cyanocobalamin – an overview | ScienceDirect Topics [Internet].
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14. Carmel R. Efficacy and safety of fortification and supplementation with vitamin B12: Biochemical and physiological effects. In: Food and Nutrition Bulletin [Internet]. 2008 .
Source

15. What Every Vegan Should Know About Vitamin B12 | The Vegan Society [Internet].
Source

16. Norris J, Messina G. B12 in Plant Foods. VeganHealth.org [Internet]. 2015 ;1–13.
Source

17. Watanabe F, Bito T. Vitamin B12 sources and microbial interaction. Exp Biol Med [Internet]. 2018 Jan 1 ;243(2):148–58.
Source

18. Watanabe F, Yabuta Y, Bito T, Teng F. Vitamin B12-containing plant food sources for vegetarians [Internet]. Vol. 6, Nutrients. MDPI AG; 2014 . p. 1861–73.
Source

19. Venkatramanan S, Armata IE, Strupp BJ, Finkelstein JL. Vitamin B-12 and Cognition in Children. Adv Nutr [Internet]. 2016 Sep 1 ;7(5):879–88.
Source

20. Andrès E, Loukili NH, Noel E, Kaltenbach G, Ben Abdelgheni M, Perrin AE, et al. Vitamin B12 (cobalamin) deficiency in elderly patients [Internet]. Vol. 171, CMAJ. 2004 . p. 251–9.
Source

21. Martínez-Cañamero A, Sánchez Muñoz B, Herrera Contreras I, Ocaña Pérez E, Gassó Campos M. Vitamin B12 and folic acid levels in the first trimester of pregnancy in a hospital in Jaen (Spain). Rev del Lab Clin [Internet]. 2013 Oct 1 ;6(4):151–6.
Source

Why you can trust me?

Scientific article
Brito A, Hertrampf E, Olivares M, Gaitán D, Sánchez H, Allen LH, et al. Folatos y vitamina B12 en la salud humana. Rev Med Chil [Internet]. 2012 Nov ;140(11):1464–75.
Go to source
Official document FESNAD
FESNAD. Ingestas Dietéticas de Referencia (IDR) para la Población Española, 2010. Act Dietética [Internet]. 2010 Oct;14(4):196–7.
Go to source
Official website
Foods highest in Vitamin B12 [Internet].
Go to source
Scientific article
Bennink Mr, Ono K. Vitamin B12, E and D Content of Raw and Cooked Beef. J Food Sci [Internet]. 1982 ;47(6):1786–92.
Go to source
Scientific article
Czerwonka M, Szterk A, Waszkiewicz-Robak B. Vitamin B12 content in raw and cooked beef. Meat Sci [Internet]. 2014 ;96(3):1371–5.
Go to source
E-book
Ankar A, Bhimji SS. Vitamin B12 Deficiency (Cobalamin) [Internet]. StatPearls. StatPearls Publishing; 2018 .
Go to source
Scientific article
González-Tarrío L, Fontana M, Romero J. Degeneración combinada subaguda medular, una complicación infrecuente de un problema frecuente en la práctica clínica: El déficit de vitamina B12. Semergen [Internet]. 2008 Oct 1 ;34(8):417–9.
Go to source
Scientific article
O’Leary F, Samman S. Vitamin B12 in Health and Disease. Nutrients [Internet]. 2010 Mar 5 ;2(3):299–316.
Go to source
Clinical guide
Formoso Fernando, Orosa Elvira CA. Guía clínica de Anemia perniciosa [Internet]. Elsevier. 2013 .
Go to source
Scientific article
Aroda VR, Edelstein SL, Goldberg RB, Knowler WC, Marcovina SM, Orchard TJ, et al. Long-term metformin use and vitamin B12 deficiency in the diabetes prevention program outcomes study. J Clin Endocrinol Metab [Internet]. 2016 ;101(4):1754–61.
Go to source
Scientific article
Pawlak R, Parrott SJ, Raj S, Cullum-Dugan D, Lucus D. How prevalent is vitamin B12 deficiency among vegetarians? [Internet]. Vol. 71, Nutrition Reviews. 2013 . p. 110–7.
Go to source
Book
Vitamin B12 Deficiency – Disorders of Nutrition – MSD Manual Consumer Version [Internet].
Go to source
E-book
Cyanocobalamin – an overview | ScienceDirect Topics [Internet].
Go to source
Scientific article
Carmel R. Efficacy and safety of fortification and supplementation with vitamin B12: Biochemical and physiological effects. In: Food and Nutrition Bulletin [Internet]. 2008 .
Go to source
The Vegan Society Official Website
What Every Vegan Should Know About Vitamin B12 | The Vegan Society [Internet].
Go to source
Official website
Norris J, Messina G. B12 in Plant Foods. VeganHealth.org [Internet]. 2015 ;1–13.
Go to source
Scientific article
Watanabe F, Bito T. Vitamin B12 sources and microbial interaction. Exp Biol Med [Internet]. 2018 Jan 1 ;243(2):148–58.
Go to source
Scientific article
Watanabe F, Yabuta Y, Bito T, Teng F. Vitamin B12-containing plant food sources for vegetarians [Internet]. Vol. 6, Nutrients. MDPI AG; 2014 . p. 1861–73.
Go to source
Scientific article
Venkatramanan S, Armata IE, Strupp BJ, Finkelstein JL. Vitamin B-12 and Cognition in Children. Adv Nutr [Internet]. 2016 Sep 1 ;7(5):879–88.
Go to source
Scientific article
Andrès E, Loukili NH, Noel E, Kaltenbach G, Ben Abdelgheni M, Perrin AE, et al. Vitamin B12 (cobalamin) deficiency in elderly patients [Internet]. Vol. 171, CMAJ. 2004 . p. 251–9.
Go to source
Scientific article
Martínez-Cañamero A, Sánchez Muñoz B, Herrera Contreras I, Ocaña Pérez E, Gassó Campos M. Vitamin B12 and folic acid levels in the first trimester of pregnancy in a hospital in Jaen (Spain). Rev del Lab Clin [Internet]. 2013 Oct 1 ;6(4):151–6.
Go to source
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