Vitamin B12 Deficiency
Last updated: November 27, 2020

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There is little doubt that you have heard of vitamin B12, this nutrient so crucial to vegans. Generally caused by a diet free of animal products, its deficiency can lead to amaemia and deterioration of the nervous system. But are people on plant-based diets the only ones who should be concerned about this issue?

In our new article, we will discuss the most important aspects of vitamin B12 deficiency. We will delve into the population groups that are at high risk of hypovitaminosis, its consequences, and how to prevent it. Are you ready to learn more about it?

Key Facts

  • Vitamin B12 deficiency is a health condition that primarily affects vegans, older adults, and individuals with intestinal or autoimmune pathologies.
  • In the long run, the depletion of vitamin B12 reserves will lead to a deterioration of health with amaemia and neurological impairment. Some of these conditions can become permanent.
  • You can prevent vitamin B12 deficiency by using fortified foods or supplements.

Our Selection: The Best Products to Prevent Vitamin B12 Deficiency in the UK

In the following section, you will discover our very own selection of the most popular supplements to help you combat this condition. All of them are made from high-quality ingredients, and thousands of users in the country have tested their efficacy. In any case, dietary products should never replace medical care. You are advised to have your blood regularly tested to make sure the supplementation is effective.

Best Vitamin B12 Gummies

If you prefer to chew on gummies for a potent vitamin B12 boost, this supplement is an excellent option. Each delicious cherry-flavoured gummy will provide you with 1,500 micrograms of cyanocobalamin. In addition, they are gluten-free and do not contain dairy products.

The new Vitafusion Extra Strength line includes high potency vitamin B12 fused into delicious gummies. Two Extra Strength B12 gummies provide 50,000% daily value (3000 mcg) of B12.

Best Vitamin B12 Easy to Swallow Supplement

With 1000 mcg, these high strength vitamin b12 supplement offers you a convenient one a day 6mm tablet to meet your daily needs as an easy to swallow serving. Vitamin B12 derived from methylcobalamin is the most bio-available form of vitamin B12. With 400 tablets per pack, you get an amazing value. Keeping you replenished for 6 months.

Vitamin B12 contributes to the reduction of tiredness and fatigue and to normal energy-yielding metabolism. Most importantly, this supplement is made and manufactured in the UK with premium ingredients to the highest of standards.

Best Vitamin B12 Liquid Supplement

Liquid extracts are an effective way to absorb vitamin B12 directly via the blood vessels in the mouth. This brands supplement is incredibly popular among users. It is a convenient, easy to take version of this versatile nutrient, and is particularly important for those with a restrictive diet. Beyond energy vitamin B12 has several health benefits supporting general vitality and well-being.

All in all this 59ml bottle of vitamin D12 supplement promotes the health of the nervous system and healthy blood cell formation. Subsequently, it supports energy metabolism, with just one full dropper up to two times a day.

Best Powder Form Vitamin B12

 

Vitamin B12 is essential for healthy red blood cells and for energy. However, it cannot be absorbed from food unless the stomach makes ‘intrinsic factor’, which may be reduced as we age or in those with poor digestion. Many people have difficulty absorbing vitamin B12 and may have deficiency symptoms. So this manufacturer presents this highly absorbable sublingual powder, maximising assimilation.

We should also mention its new and improved taste with tooth-friendly xylitol. Suitable for children and elderly people. With a new long-handled scoop. Please, do not feed xylitol to dogs; if consumed, seek veterinary advice.

Best Food Enriched With Vitamin B12

Nutritional yeast is found in most vegan and vegetarian people’s pantries. This highly nutritious food isn’t just a great way to add flavour to your recipes; it’s rich in different vitamin B12 and minerals and is known to offer various health benefits. The yeast flakes are completely suitable for vegans, which should come as some relief as there is no contest when it comes to cheese substitutes.

It is great to know that their flakes provide one of the richest natural sources of the B-group vitamins and trace elements. And better still it is 100 % natural, made from a strain of Saccharomyces Cerevasiae, grown on enriched purified molasses. The conditions are carefully controlled, which ensures complete abstinence from candida albicans yeast.

Everything You Should Know About Vitamin B12 Deficiency

Natural aging, damage to the digestive tract, and plant-based diets can all lead to a depletion of the body’s reserves of vitamin B12. The prevention and treatment of this condition are essential to avoid severe and permanent disorders such as dementia or blindness.

Woman and child laughing with fresh food

People who eat meat have higher levels of vitamin B12 than vegans.
(Source: Choreograph: 106032815/ 123rf.com)

Why is vitamin B12 deficiency considered a problem?

Vitamin B12 (cobalamin) plays an essential role in your metabolism. This molecule is necessary for the production of amino acids and the proper synthesis of cellular DNA. It acts synergistically with folic acid, contributing to the formation of blood cells and the preservation of nerve function (1, 2).

If your vitamin B12 levels are insufficient, DNA formation in new cells is impossible. The synthesis of myelin, a substance that surrounds nerve fibres, will also be reduced. In addition, the paralysis of enzymatic processes will lead to the deposition of molecules such as homocysteine.

  1. If your organism cannot create new cells, you will have amaemia. At a microscopic level, you can observe how the cellular precursors grow in size, preparing for a division that isn’t possible due to the B12 deficiency. This is known as megaloblastic amaemia, which literally means few large-size blood cells (3).
  2. If your nervous system loses its protective lining, it will undergo degenerative changes. Nerve fibres need to be protected by the myelin sheath in order to transmit electrical impulses to the brain. A lack of B12 will cause demyelination; this affects your balance, vision, memory, and concentration, among other things (1, 4).
  3. If a homocysteine deposit occurs, the cardiovascular risk may increase. Some studies have linked increased plasma homocysteine concentrations to a higher risk of cardiovascular events or stroke. These findings are currently under study (5, 6).

These alterations will harm your quality of life. Megaloblastic amaemia will decrease your resistance to fatigue. At the same time, degeneration of the nervous system can cause you to experience brain fog, the lack of concentration that vegans worry about so much. We have listed more symptoms of vitamin B12 deficiency in the following table (3, 4, 6, 7):

Symptom or sign Description
Fatigue Consequence of the inability of red blood cells to transport oxygen and nutrients to the muscles. It can lead to reduced athletic performance and muscle pain.
Skin paleness This is due to reduced red blood cells. If you have a yellowish tone, you may suffer from hepatic alteration.
Digestive alterations Digestive lesions may appear, resulting in diarrhoea, nausea, an increase in the size of the liver, and loss of appetite, with the consequent weight loss.
Palpitations They are a consequence of amaemia. Oxygen transport decreases, forcing the heart to beat at a higher-than-normal rate to supply the demands of the organism.
Behavioral alterations Unexplained sadness, irritability, or apathy have been reported as a consequence of vitamin B12 deficiency.
Intellectual alterations This is a sign of neurological degeneration. They can manifest themselves as difficulty concentrating (brain fog), alterations in memory, or a decrease in mental performance. If it is not treated, it can lead to dementia and hallucinations.
Clumsiness Consequence of the deterioration of the neurological systems responsible for your balance.
Sensitivity alterations Consequence of the deterioration of the neurological system. They can appear in the form of pain or tingling (paresthesias).
Visual alterations This is a rare but severe consequence of B12 deficiency (optical neuropathy). If left untreated, it can lead to blindness.
Developmental alterations in the foetus In pregnant women, B12 deficiency has been associated with an increased rate of malformations in the foetus.
Elevation of cardiovascular risk (controversial) Some studies link the elevation of homocysteine concentrations with an increased risk of coronary pathology or stroke. Hypothesis currently under study.

Am I exposed to vitamin B12 deficiency?

Some people are at higher risk than others to suffer from this condition. Certain lifestyles, many drugs, and specific diseases can make it difficult to absorb or store cobalamin, increasing the chances of being deficient. In the following lines, we will answer the most frequently asked questions regarding this:

I’m a vegan. Am I at risk? Vitamin B12 is found almost exclusively in foods of animal origin. Individuals following plant-based diets cannot get the cobalamin they need naturally, which is why they have to turn to supplements or fortified foods (8, 9).

I am an ovo-lacto vegetarian. Can I have low vitamin B12 levels? Dairy products and eggs contain small amounts of cobalamin. The intake of B12 from these foods may be insufficient, depending on the individual. Some experts recommend that vegetarians supplement to prevent any deficiencies (9, 10, 11, 12).

I often eat meat. Why do I have low B12 levels? Diet isn’t the only factor that predisposes to this type of deficiency. As you will see in the table below, B12 levels can be lowered by any kind of gastrointestinal injury or condition, in response to chronic illness, or as a result of natural processes such as aging (4, 13).

In the table below, we have listed the many possible causes of vitamin B12 deficiency:

Cause Description
Gastric pathology Pernicious amaemia (intrinsic factor deficit)

Consequence of stomach surgery

Consumption of toxic substances

Functional diseases (alterations in the secretion of gastric acid)

Intestinal malabsorption Pancreatic diseases

Zollinger-Ellison type malabsorptive syndromes

Infections by bacteria or parasites

Surgical bowel resection

Crohn’s disease

Medication and drugs HIV treatment

Antibiotic treatments

Oral contraceptives

Methotrexate

Chemotherapy drugs

Nitrous oxide

Metformin

Other causes Congenital diseases

Heart failure

Hyperthyroidism

Increased needs during pregnancy

As you can see, your risk of a vitamin B12 deficiency will depend on a variety of factors. While you can manage some of them (such as your diet), others (after-effects of surgery, autoimmune diseases, or drug treatment) are out of your control. Consult a health professional if you think you have any of the conditions listed above.

Food rich in vitamin B12

Vitamin B12 deficiency can cause amaemia and alterations in the nervous system.
(Source: Elena: 73882253/ 123rf.com)

How can I prevent vitamin B12 deficiency?

Fortunately, this is quite straightforward in young, healthy people. From the age of 14 onward, it is recommended to take 2-2.5 micrograms (mcg) of cobalamin per day to prevent any deficiency. Children and pregnant women will have slightly different requirements, as you can see in the following table (16, 17, 18):

Population group Recommended daily allowance (RDA)
Babies, 0-6 months 0.4
Babies, 7-12 months 0,5
Children, 1 to 3 years old 0.9
Children, 4 to 8 years old 1.2
Children, 9 to 13 years old 1.8
Men and women from 14 years old 2.5
Pregnant women 2.6
Breastfeeding women 2.8

A balanced diet is the first step toward keeping your vitamin B12 reserves full. Animal-based products will be the main source of cobalamin for omnivorous individuals. The largest amounts of B12 are found in molluscs and the entrails (such as the liver or kidneys) of animals (19).

Food (100 grams/millilitres) Amount of B12 (micrograms)
Canned clams 99
Lamb liver 90
Veal liver 83
Squid 36
Mackerel 19
Turkey meat 9
Foie gras 9
Egg 5
Milk 4
Pork 1

Individuals who do not consume products of animal origin for ethical, religious, or health reasons won’t be able to take advantage of the B12 content of these foods. This is why they are advised to consume fortified foods or supplements. The vitamin B12 present in these products is of bacterial origin, which means that no animal needs to be killed to obtain it.

  • Fortified foods: You can find yeasts, vegetable drinks, and cereals enriched with vitamin B12 in any specialized store or online. These products will provide you with varying amounts of cobalamin. You may need to include several of these foods in your daily diet to meet your RDA for vitamin B12.
  • Vitamin B12 supplements: These nutritional products contain high concentrations of synthetic (cyanocobalamin) or natural (hydroxocobalamin, methylcobalamin, or adenosylcobalamin) vitamin B12. Injectable supplements are used by doctors, while oral preparations in the form of drops, pills, or sublingual tablets are readily available in supermarkets and online.

How should I use vitamin B12 supplements?

Vitamin B12 supplementation is considered safe, simple, and inexpensive. Cyanocobalamin or hydroxocobalamin injections are prescribed by health centres, which will indicate the appropriate dose (1,000-5,000 mcg every other day, weekly or monthly) depending on your needs.

Oral supplements, on the other hand, may be prescribed by a health professional or purchased directly by the consumer. If you buy them yourself, keep in mind that there are different dosage guidelines based on certain characteristics. We have listed them below (20, 21):

Dosage Guideline Target population
25-100 mcg Daily Elderly population (WebMD)
1 mcg Three times a day Young, healthy vegans (The Vegan Society)
At least 10 mcg Once a day Young, healthy vegans (The Vegan Society)
2,000 mcg Once a week Young, healthy vegans (The Vegan Society)

You should always check the label of your vitamin B12 supplement for the manufacturer’s instructions regarding use and recommended doses. You can also ask your physician for more information. While they are considered safe, these products may cause digestive discomfort or allergic reactions. In addition, they interact with certain medications (such as chloramphenicol) (20, 22).

Seafood

Mollusks are rich in vitamin B12.
(Source: Teen00000: 83995643/ 123rf.com)

Buyer’s Guide

In the section below, we will delve into the main characteristics of products designed to keep B12 deficiency at bay. In any case, remember that your intestinal tract must be able to absorb this vitamin if you want to make the most of these supplements and fortified foods.

Foods Fortified With Vitamin B12

Flour, breakfast cereals, soy drinks, and yeast are available to enrich your dishes. Their price will depend on the type of food you want to purchase. Generally, you can expect them to cost a few pounds more than their standard counterparts, although the quantity you buy naturally influences this.

High-quality fortified foods will feature detailed nutritional information about the type of vitamin B12 they contain. It should either be active or bioavailable. In addition, you should cook these products with caution; cobalamin is unstable at high temperatures.

Woman smiling in the kitchen

Some diseases can cause vitamin B12 deficiency.
(Source: Leenanuruksa: 117629911/ 123rf.com)

Multivitamins With Vitamin B12

What would a multivitamin supplement be without vitamin B12? Virtually all of these nutritional products contain cyanocobalamin or methylcobalamin. However, they are often intended for omnivores. If you plan to make them your only source of B12, make sure they provide at least 100% of your RDA.

Multivitamin supplements are generally very affordable, although this will depend on the manufacturer and the ingredients they contain. In the table below, you can get a rough idea of their prices compared to vitamin B12 supplements:

Type of supplement Vitamin B12 content (mcg) Average price per 100 capsules
Vitamin B12 1,000 £10
Multivitamins for vegans 50 £12
B vitamins 25 £14
Multivitamins and multiminerals 20 £20
Multivitamins, multiminerals, and fruit extracts 250 £30

B12 Supplements for Daily Use

Most commercially available vitamin B12 dietary products are sold as daily-use items. The synthetic (cyanocobalamin) or natural (methyl, hydroxyl, and adenosylcobalamin) cobalamin content of these supplements ranges from 100 to 5,000 micrograms. They are marketed in the form of capsules, chewable tablets, or liquid extract.

Since there have been no reports of severe effects from excessive intake of vitamin B12, many brands choose to administer large doses to achieve greater bioavailability. However, we warn you that the prestigious vegan organization The Vegan Society advises not to exceed 5,000 micrograms of vitamin B12 per week.

Dr. Dawn HarperIn Live Well to 101: A Practical Guide to Achieving a Long and Healthy Life
“Water-soluble vitamins (vitamins B and C) can be destroyed by heat and they can be lost in water used for cooking. Wherever possible, steam or grill food to ensure the vitamin content is preserved.”

Summary

Vitamin B12 deficiency is a common problem that can take many of us by surprise. If you don’t carefully monitor your intake and absorption of this vitamin, you may suffer from amaemia and neuropsychiatric disorders. The consequences of this nutritional deficiency can lead to debilitating diseases.

Fortunately, you now have access to a variety of dietary products that will provide you with the vitamin B12 supply you need. Fortified foods and supplements help keep vegan and vegetarian individuals healthy, while injections are designed for anyone who cannot absorb cobalamin properly.

Did you find our guide on vitamin B12 deficiency helpful and informative? Feel free to tell us your experience in the comments section below; we’d love to hear from you! You can also share this article on your social media so that your friends and family also learn how to tackle this growing problem.

(Featured Image Source: Tatjana: 66526178/ 123rf.com)

References (26)

1. Ankar A, Bhimji SS. Vitamin B12 Deficiency (Cobalamin) [Internet]. StatPearls. StatPearls Publishing; 2018 [2020 Apr 5].
Source

2. Vitamin B12 - Health Encyclopedia - University of Rochester Medical Center [Internet]. [2020 Apr 8].
Source

3. Malek E, Sacher RA. Megaloblastic Anemia. In: Pathobiology of Human Disease [Internet]. Elsevier; 2014 [2020 Apr 5]. p. 1499–505.
Source

4. 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 [2020 Apr 12];34(8):417–9.
Source

5. Allen LH, Miller JW, De Groot L, Rosenberg IH, Smith AD, Refsum H, et al. Biomarkers of Nutrition for Development (BOND): Vitamin B-12 Review [Internet]. Vol. 148, Journal of Nutrition. 2018 [2020 Apr 10]. p. 1995S-2027S.
Source

6. Chrysant SG, Chrysant GS. The current status of homocysteine as a risk factor for cardiovascular disease: a mini review [Internet]. Vol. 16, Expert Review of Cardiovascular Therapy. Taylor and Francis Ltd; 2018 [2020 Apr 12]. p. 559–65.
Source

7. Shane B. Folate and vitamin B12, metabolism: Overview and interaction with riboflavin, vitamin B6, and polymorphisms. In: Food and Nutrition Bulletin [Internet]. 2008 [2020 Apr 12]. p. S5–16.
Source

8. 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 [2020 Apr 4]. p. 110–7.
Source

9. Woo KS, Kwok TCY, Celermajer DS. Vegan diet, subnormal vitamin B-12 status and cardiovascular health [Internet]. Vol. 6, Nutrients. MDPI AG; 2014 [2020 Apr 4]. p. 3259–73.
Source

10. Buil Arasanz ME, Bobé Armant F, Allué Buil AI, Trubat Muñoz G. Vitamina B12 y dieta vegetariana. Semergen [Internet]. 2009 Oct 1 [2020 Apr 10];35(8):412–4.
Source

11. Koebnick C, Hoffmann I, Dagnelie PC, Heins UA, Wickramasinghe SN, Ratnayaka ID, et al. Long-Term Ovo-Lacto Vegetarian Diet Impairs Vitamin B-12 Status in Pregnant Women. J Nutr [Internet]. 2004 Dec [2020 Apr 12];134(12):3319–26.
Source

12. O’Leary F, Samman S. Vitamin B12 in Health and Disease. Nutrients [Internet]. 2010 Mar 5 [2020 Apr 5];2(3):299–316.
Source

13. Acezat Oliva J, Simó Cruzet E. Déficit de vitamina B12 en pacientes tratados con metformina: Pautas de actuación [Internet]. Vol. 42, Atencion Primaria. Elsevier; 2010 [2020 Apr 10]. p. 186–7.
Source

14. Rodríguez de Cossío A, Rodríguez Sánchez R. Pruebas de laboratorio en Atención Primaria (I). Semer - Med Fam [Internet]. 2011 Jan 1 [2020 Apr 12];37(1):15–21.
Source

15. Vashi P, Edwin P, Popiel B, Lammersfeld C, Gupta D. Methylmalonic acid and homocysteine as indicators of Vitamin B-12 deficiency in cancer. Sengupta S, editor. PLoS One [Internet]. 2016 Jan 25 [2020 Apr 12];11(1):e0147843.
Source

16. Buil Arasanz ME, Bobé Armant F, Allué Buil AI, Trubat Muñoz G. Vitamina B12 y dieta vegetariana. Semer - Med Fam [Internet]. 2009 Oct 1 [2020 Apr 8];35(8):412–4.
Source

17. National Institutes of Health. Vitamina B12 — Datos en español [Internet]. 17 de febrero. 2016 [2020 Apr 7].
Source

18. JE. Mariño Suáreza, I. Monedero Recuerob CPL. Deficiencia de vitamina B 12 y tratamiento por vía oral. Una opción tan eficaz como (todavía) poco utilizada | Atención Primaria [Internet]. [2020 Apr 10].
Source

19. Departamento de Agricultura de Estados Unidos (USDA). FoodData Central [Internet]. FoodData Central. 2019 [2020 Apr 8]. p. fdc.nal.usda.gov.
Source

20. Vitamin B12: Uses, Side Effects, Interactions, Dosage, and Warning [Internet]. [2020 Apr 8].
Source

21. What Every Vegan Should Know About Vitamin B12 | The Vegan Society [Internet]. [2020 Apr 4].
Source

22. Vitamin B12 Side Effects: Common, Severe, Long Term - Drugs.com [Internet]. [2020 Apr 8].
Source

23. Norris J, Messina G. B12 in Plant Foods. VeganHealth.org [Internet]. 2015 [2020 Apr 13];1–13.
Source

24. Watanabe F, Bito T. Vitamin B12 sources and microbial interaction. Exp Biol Med [Internet]. 2018 Jan 1 [2020 Apr 13];243(2):148–58.
Source

25. Watanabe F, Yabuta Y, Bito T, Teng F. Vitamin B12-containing plant food sources for vegetarians [Internet]. Vol. 6, Nutrients. MDPI AG; 2014 [2020 Apr 13]. p. 1861–73.
Source

26. Venkatramanan S, Armata IE, Strupp BJ, Finkelstein JL. Vitamin B-12 and Cognition in Children. Adv Nutr [Internet]. 2016 Sep 1 [2020 Apr 13];7(5):879–88.
Source

Why you can trust me?

Clinical guide
Ankar A, Bhimji SS. Vitamin B12 Deficiency (Cobalamin) [Internet]. StatPearls. StatPearls Publishing; 2018 [2020 Apr 5].
Go to source
Virtual Encyclopedia
Vitamin B12 - Health Encyclopedia - University of Rochester Medical Center [Internet]. [2020 Apr 8].
Go to source
Review article
Malek E, Sacher RA. Megaloblastic Anemia. In: Pathobiology of Human Disease [Internet]. Elsevier; 2014 [2020 Apr 5]. p. 1499–505.
Go to source
Review 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 [2020 Apr 12];34(8):417–9.
Go to source
Review article
Allen LH, Miller JW, De Groot L, Rosenberg IH, Smith AD, Refsum H, et al. Biomarkers of Nutrition for Development (BOND): Vitamin B-12 Review [Internet]. Vol. 148, Journal of Nutrition. 2018 [2020 Apr 10]. p. 1995S-2027S.
Go to source
Review article
Chrysant SG, Chrysant GS. The current status of homocysteine as a risk factor for cardiovascular disease: a mini review [Internet]. Vol. 16, Expert Review of Cardiovascular Therapy. Taylor and Francis Ltd; 2018 [2020 Apr 12]. p. 559–65.
Go to source
Review article
Shane B. Folate and vitamin B12, metabolism: Overview and interaction with riboflavin, vitamin B6, and polymorphisms. In: Food and Nutrition Bulletin [Internet]. 2008 [2020 Apr 12]. p. S5–16.
Go to source
Review 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 [2020 Apr 4]. p. 110–7.
Go to source
Review article
Woo KS, Kwok TCY, Celermajer DS. Vegan diet, subnormal vitamin B-12 status and cardiovascular health [Internet]. Vol. 6, Nutrients. MDPI AG; 2014 [2020 Apr 4]. p. 3259–73.
Go to source
Review article
Buil Arasanz ME, Bobé Armant F, Allué Buil AI, Trubat Muñoz G. Vitamina B12 y dieta vegetariana. Semergen [Internet]. 2009 Oct 1 [2020 Apr 10];35(8):412–4.
Go to source
Scientific article
Koebnick C, Hoffmann I, Dagnelie PC, Heins UA, Wickramasinghe SN, Ratnayaka ID, et al. Long-Term Ovo-Lacto Vegetarian Diet Impairs Vitamin B-12 Status in Pregnant Women. J Nutr [Internet]. 2004 Dec [2020 Apr 12];134(12):3319–26.
Go to source
Review article
O’Leary F, Samman S. Vitamin B12 in Health and Disease. Nutrients [Internet]. 2010 Mar 5 [2020 Apr 5];2(3):299–316.
Go to source
Guidelines for action
Acezat Oliva J, Simó Cruzet E. Déficit de vitamina B12 en pacientes tratados con metformina: Pautas de actuación [Internet]. Vol. 42, Atencion Primaria. Elsevier; 2010 [2020 Apr 10]. p. 186–7.
Go to source
Clinical guide
Rodríguez de Cossío A, Rodríguez Sánchez R. Pruebas de laboratorio en Atención Primaria (I). Semer - Med Fam [Internet]. 2011 Jan 1 [2020 Apr 12];37(1):15–21.
Go to source
Review article
Vashi P, Edwin P, Popiel B, Lammersfeld C, Gupta D. Methylmalonic acid and homocysteine as indicators of Vitamin B-12 deficiency in cancer. Sengupta S, editor. PLoS One [Internet]. 2016 Jan 25 [2020 Apr 12];11(1):e0147843.
Go to source
Review article
Buil Arasanz ME, Bobé Armant F, Allué Buil AI, Trubat Muñoz G. Vitamina B12 y dieta vegetariana. Semer - Med Fam [Internet]. 2009 Oct 1 [2020 Apr 8];35(8):412–4.
Go to source
Official website
National Institutes of Health. Vitamina B12 — Datos en español [Internet]. 17 de febrero. 2016 [2020 Apr 7].
Go to source
Review article
JE. Mariño Suáreza, I. Monedero Recuerob CPL. Deficiencia de vitamina B 12 y tratamiento por vía oral. Una opción tan eficaz como (todavía) poco utilizada | Atención Primaria [Internet]. [2020 Apr 10].
Go to source
Official website
Departamento de Agricultura de Estados Unidos (USDA). FoodData Central [Internet]. FoodData Central. 2019 [2020 Apr 8]. p. fdc.nal.usda.gov.
Go to source
Official website
Vitamin B12: Uses, Side Effects, Interactions, Dosage, and Warning [Internet]. [2020 Apr 8].
Go to source
Web - The Vegan Society
What Every Vegan Should Know About Vitamin B12 | The Vegan Society [Internet]. [2020 Apr 4].
Go to source
Official website
Vitamin B12 Side Effects: Common, Severe, Long Term - Drugs.com [Internet]. [2020 Apr 8].
Go to source
Web - Veganhealt
Norris J, Messina G. B12 in Plant Foods. VeganHealth.org [Internet]. 2015 [2020 Apr 13];1–13.
Go to source
Review article
Watanabe F, Bito T. Vitamin B12 sources and microbial interaction. Exp Biol Med [Internet]. 2018 Jan 1 [2020 Apr 13];243(2):148–58.
Go to source
Review article
Watanabe F, Yabuta Y, Bito T, Teng F. Vitamin B12-containing plant food sources for vegetarians [Internet]. Vol. 6, Nutrients. MDPI AG; 2014 [2020 Apr 13]. p. 1861–73.
Go to source
Review article
Venkatramanan S, Armata IE, Strupp BJ, Finkelstein JL. Vitamin B-12 and Cognition in Children. Adv Nutr [Internet]. 2016 Sep 1 [2020 Apr 13];7(5):879–88.
Go to source