Vitamin B12 is a water-soluble vitamin, which is a part of the vitamin B complex. It is naturally present in certain food items, and is also available as a dietary supplement and prescription medication

Vitamin B12 has several health benefits. It is vital for the formation of red blood cells, which prevents the development of anaemia. Vitamin B12 is also beneficial for your skin and hair. 

This article discusses the sources of vitamin B12 and its benefits, along with the recommended age-wise daily dosage.

  1. Sources of Vitamin B12
  2. Vitamin B12 benefits
  3. Vitamin B12 daily requirement
  4. Vitamin B12 deficiency
  5. Vitamin B12 side effects

Vitamin B12 is available in different forms, namely cyanocobalamin and methylcobalamin, the latter is naturally occurring while the former is available as a supplement.

Being inherently present in animal products, methylcobalamin is the more bioavailable and preferred form of vitamin B12 as compared to the other form. It is also better absorbed by the body and can be stored for longer durations without causing any serious side effects. Our body relies more on methylcobalamin for its optimal functioning. That is why, if cyanocobalamin supplements are taken, they are converted to methylcobalamin for use in the body. 

Vitamin B12 is found in a variety of foods, particularly those derived from animal sources. But, there are plenty of vegan and vegetarian options as well. Let's have a look at the two.

Vitamin B12 foods: Animal sources

Vitamin B12 is naturally present in animal food products. You can include the following sources in your daily routine if you happen to be a non-vegetarian:

  • Milk and milk products like cream, cheese (ricotta cheese, mozzarella cheese, swiss cheese), cottage cheese (paneer), yoghurt or dahi
  • Eggs
  • Fishes like salmon, trout, sardines or tuna
  • Shrimp
  • Clams
  • Oyster
  • Pork
  • Liver
  • Ham
  • Chicken breast
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Vitamin B12 foods: vegan

If you are on a strict vegan diet (vegetarian, non-dairy diet) diet or are lactose intolerant (inability to digest milk products), you can include the following sources in your diet:

  • Almond milk
  • Soy milk
  • Coconut milk
  • Yeast
  • Fortified breakfast cereals
  • Leafy greens like spinach and kale

Other than these sources, vitamin B12 is available as supplements, which may be required for vegetarians, but it is recommended to not take them without a physician’s prescription. Vitamin B12 is also present in B complex supplements, taking which also requires a physician's consultation.

Read more: Soybean benefits

Vitamin B12 performs several functions because of which it is an essential vitamin for your body.

It is required for the formation of RBCs (red blood cells), normal cell division and formation and maintenance of bone, skin, teeth and nails.

It is also essential for the metabolism of homocysteine, which may have a role in the prevention of cancer. These and other important health benefits of vitamin B12 are explained below.

  • For skin: Vitamin B12 moistens and soothes the skin and scalp. It is known to prevent skin conditions like eczema and hyperpigmentation along with enhancing the process of wound healing.
  • Promotes oral health: Deficiency of vitamin B12 is associated with oral conditions such as angular stomatitis and glossitis, which refer to inflammation in the angles of mouth and tongue respectively. So, it is important to take sufficient amount of this vitamin in your diet.
  • Prevents pernicious anaemia: Pernicious anaemia is a reduction in RBCs caused due to a deficiency in vitamin B12. It causes fatigue, weakness, constipation and headache. Consuming the recommended amount of b12 vitamin would help prevent this condition.
  • For heart: Optimum levels of vitamin B12 prevents the damaging effects of homocysteine (an amino acid) on the cardiovascular system, thus reducing the risk of heart attacks and stroke.
  • For brain: B12 is known to protect brain function and prevent depression. It also reduces the risk of neurodegenerative diseases such as Alzheimer’s and Parkinson’s.
  • For postmenopausal women: Vitamin B12 counters the deteriorating effects of homocysteine on bones, which is otherwise responsible for an increased risk of fractures and osteoporosis in postmenopausal women. Research evidence indicates that optimum levels of this vitamin are helpful in reducing the risk of breast cancer.

Vitamin B12 for skin

Vitamin B12 is crucial for your skin, hair and nails and helps in keeping their health. It ensures proper skin hydration and enough moisture, which helps in avoiding dryness of skin. Vitamin B12 is often a constituent of skin creams and lotions and is found to be beneficial for individuals with dry skin. For these reasons, it is also useful in treating and avoiding disorders associated with dryness of skin, like eczema. Topical vitamin B12 has been found to be beneficial in the treatment of eczema, particularly in children.

A deficiency of vitamin B12 is associated with several other cutaneous manifestations, like hyperpigmentation (excessive pigmentation of skin forming dark patches) of skin and vitiligo (loss of skin colour in patches).

Hyperpigmentation of the skin due to deficiency of vitamin B12 is, however, reversible. Research evidence has suggested that intramuscular injections of cyanocobalamin can reduce pigmentation and have the potential to normalize the skin colour in the affected area.

Other than this, vitamin B12 is known to aid in proper wound healing. Topical application of vitamin B12 enhances the physiological process of wound healing. Since vitamin B12 promotes hair and nail health, a deficiency of this vitamin often leads to brittle nails and hair. To avoid these manifestations, it is suggested to add more vitamin B12 to your diet. You can also opt for over the counter products to enhance your hair and skin health.

Read more: How to get glowing skin

Vitamin B12 for oral health

As stated, vitamin B12 is essential for the health of your skin and mucous membranes, which includes your oral mucosa.

A deficiency of this vitamin has been commonly associated with

  • Angular stomatitis: inflammation of the angles of the mouth
  • Glossitis: inflammation of the tongue
  • Aphthous ulcers and aphthous stomatitis: small and shallow lesions within the mouth

Read more: Inflammatory diseases

Thus, to avoid these conditions and to maintain the best health of your oral cavity, it is recommended to increase the intake of vitamin B12 rich foods.

Read more: Oral hygiene tips

Vitamin B12 prevents pernicious anemia

Vitamin B12 deficiency anaemia or pernicious anaemia, as the name suggests is caused when the body cannot produce enough RBCs due to a deficiency of vitamin B12.

In this type of anaemia, lesser than usual number of RBCs are present in the blood, which are larger in size. Vitamin B12 helps in the division of RBCs, and in its deficiency, RBCs become large and malformed. This can occur due to dietary deficiency of vitamin B12 or its poor absorption by the body.

Deficiency is more common in vegans or vegetarians. Symptoms of pernicious anaemia include fatigue, nausea, constipation, vomiting, headache and in severe cases where nerve damage has occurred, feeling of tingling or numbing in fingers.

To avoid this disease, it is recommended to consume sufficient amounts of vitamin B12 in your diet.

Vitamin B12 for the heart

Deficiency of vitamin B12 is associated with an increased level of homocysteine in the body. Homocysteine is an amino acid present in the body, higher levels of which can be damaging. It is known to increase the risk of cardiovascular disorders and is a potential risk factor for heart attacks. Increased levels of homocysteine in the blood are known to increase the risk of cardiovascular disorders including heart attack and stroke by 20%. Since higher levels of this amino acid are associated with vitamin B12 deficiency, supplementing your diet with foods rich in vitamin B12 may have a protective role on your heart.

Research evidence has also supported this notion stating that supplementation with vitamin B12 may have a protective effect on the heart. For this purpose, vitamin B12 supplements are often prescribed to vegetarians who are more likely to suffer from its deficiency. They must however not be taken without a doctor’s prescription.

Vitamin B12 for eyes

As already stated, vitamin B12 helps in reducing the levels of homocysteine in your body, which has several other damaging effects. Increased levels of homocysteine is found to be a risk factor for age-related macular degeneration or AMD (gradual loss/blurring of vision with advancing age) in the eyes. High levels of homocysteine and a deficiency of vitamin B12 is a modifiable risk factor, which can be managed by adding vitamin B12 rich foods in your diet before macular degeneration has taken place. Several studies have suggested that daily supplementation with vitamin B12 may reduce the risk of AMD. 

Read more: How to improve eyesight

Vitamin B12 for the brain

Having a poor diet, low in vitamin B12 is likely to increase the levels of homocysteine in the body, which is a predictor of serious health problems, like Alzheimer's or dementia, concerning the brain. Poor concentration and judgment are other common complications of high homocysteine levels. These effects are however reversible with the help of dietary supplementation of vitamin B12 and folic acid, as per various researchers. This is found to be helpful even in individuals who have normal levels of vitamin B12.

Read more: How to improve brain power

Vitamin B12 reduces depression

Depression is a mood disorder characterized by persistent feelings of sadness, lack of interest and hopelessness, affecting more than 4.5% of the Indian population. Due to constant mood swings and hormonal changes during pregnancy, depression is more likely to occur in pregnant women. A deficiency of vitamin B12 further potentiates the symptoms of depression and feelings of sadness.

In a study involving community-dwelling women, it was observed that a deficiency of vitamin B12 caused a twofold increase in the risk of severe depression. It has also been found that alongside the conventional treatment of depression involving antidepressants, supplementation with vitamin B12 was helpful in its management.

Read more: Depression in pregnancy

Vitamin B12 for women

Deficiency of vitamin B12 and an increased level of homocysteine has an effect on the bone density and increases the risk of fractures and falls. These effects are often more pronounced in women, and a deficiency of vitamin B12 is a significant yet modifiable risk factor for osteoporosis. It has been evidenced that women with a lower level of vitamin B12 are more prone to developing osteoporosis.

Studies have suggested that an increase in the levels of vitamin B12 is likely to improve bone health and reduce the risk of fractures in postmenopausal women. Low levels of vitamin B12 often cause bone loss in women, particularly around the hip.

Read more: Menopause symptoms

Other than restoring bone health in women, vitamin B12 is also associated with lower risk of certain types of cancer. Studies have shown that an intake of vitamin B12 is associated with a reduced risk of breast cancer.

It is thus highly beneficial for women to include more dietary sources of vitamin B12 in their diet.

Read more: Health tips for women in their 30s

Vitamin B12 is required in different amounts by the body, depending on your age, weight, height, etc. These are the average recommended dosages of vitamin B12:

  • Birth to 6 months- 0.4 mcg
  • 7 months to 1 year- 0.5 mcg
  • 1 year to 3 years- 0.9 mcg
  • 4 years to 8 years- 1.2 mcg
  • 9 years to 13 years- 1.8 mcg
  • 14 years to 18 years- 2.4 mcg
  • Adult dosage- 2.4 mcg
  • Dosage in pregnancy- 2.6 mcg

You can include more food sources of vitamin B12 in your diet to meet these requirements. It is not advisable to take any supplements without consulting with your doctor.

Vitamin B12 deficiency occurs due to a limited dietary intake of vitamin B12 or its poor absorption by the body, owing to certain digestive disorders. As already stated, a deficiency of vitamin B12 can lead to pernicious anaemia. Some other common symptoms of deficiency are weakness, fatigue and numbness or tingling sensations in the limbs.

Since deficiency is more common among vegetarians and the elderly, they are recommended to undergo regular checkups to maintain adequate levels of this vitamin. Checkups are particularly recommended for children, in order to avoid future deficiencies.

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Dietary consumption of vitamin B12 is not likely to cause any side effects since they usually do not exceed the recommended daily allowance. Higher doses of 1 mg are preferred in the treatment of conditions like pernicious anaemia without any observable side effects. However, a few side effects are observed with cyanocobalamin injection, which are as follows:

In severe cases, anaphylaxis reaction can occur, in which, wheezing, shortness of breath, rash, fast heartbeat, difficulty in breathing or difficulty swallowing may occur.

Immediately see your doctor if any of these side effects are observed.

Medicines / Products that contain Vitamin B12


  1. Januchowski R. Evaluation of topical vitamin B(12) for the treatment of childhood eczema. J Altern Complement Med. 2009 Apr;15(4):387-9. PMID: 19368512
  2. Rajendran Kannan. Cutaneous lesions and vitamin B12 deficiency. Can Fam Physician. 2008 Apr; 54(4): 529–532. PMID: 18413300
  3. Noppakun N, Swasdikul D. Reversible hyperpigmentation of skin and nails with white hair due to vitamin B12 deficiency. Arch Dermatol. 1986 Aug;122(8):896-9. PMID: 3740873
  4. Rembe JD, Fromm-Dornieden C, Stuermer EK. Effects of Vitamin B Complex and Vitamin C on Human Skin Cells: Is the Perceived Effect Measurable?. Adv Skin Wound Care. 2018 May;31(5):225-233. PMID: 29672394
  5. Demir N et al. Dermatological findings of vitamin B12 deficiency and resolving time of these symptoms. Cutan Ocul Toxicol. 2014 Mar;33(1):70-3. PMID: 24303868
  6. Brescoll J, Daveluy S. A review of vitamin B12 in dermatology. Am J Clin Dermatol. 2015 Feb;16(1):27-33. PMID: 25559140
  7. Pawlak R. Is vitamin B12 deficiency a risk factor for cardiovascular disease in vegetarians? Am J Prev Med. 2015 Jun;48(6):e11-26. PMID: 25998928
  8. Peirong Huang et al. Homocysteine and the risk of age-related macular degeneration: a systematic review and meta-analysis. Sci Rep. 2015; 5: 10585. PMID: 26194346
  9. Seddon JM1, Gensler G, Klein ML, Milton RC. Evaluation of plasma homocysteine and risk of age-related macular degeneration. Am J Ophthalmol. 2006 Jan;141(1):201-3. PMID: 16387004
  10. Malouf M, Grimley EJ, Areosa SA. Folic acid with or without vitamin B12 for cognition and dementia. Cochrane Database Syst Rev. 2003;(4):CD004514. PMID: 14584018
  11. National Institute of Mental Health [Internet] Bethesda, MD; Depression. National Institutes of Health; Bethesda, Maryland, United States
  12. Penninx BW et al. Vitamin B(12) deficiency and depression in physically disabled older women: epidemiologic evidence from the Women's Health and Aging Study. Am J Psychiatry. 2000 May;157(5):715-21. PMID: 10784463
  13. Ehsan Ullah Syed, Mohammad Wasay, Safia Awan. Vitamin B12 Supplementation in Treating Major Depressive Disorder: A Randomized Controlled Trial. Open Neurol J. 2013; 7: 44–48. PMID: 24339839
  14. Molloy AM, Kirke PN, Brody LC, Scott JM, Mills JL. Effects of folate and vitamin B12 deficiencies during pregnancy on fetal, infant, and child development. Food Nutr Bull. 2008 Jun;29(2 Suppl):S101-11; discussion S112-5. PMID: 18709885
  15. Potter C et al. Maternal Red Blood Cell Folate and Infant Vitamin B12 Status Influence Methylation of Genes Associated with Childhood Acute Lymphoblastic Leukemia. Mol Nutr Food Res. 2018 Nov;62(22):e1800411. PMID: 30192066
  16. Senousy SM et al. Association between biomarkers of vitamin B12 status and the risk of neural tube defects. J Obstet Gynaecol Res. 2018 Oct;44(10):1902-1908. PMID: 30043514
  17. Swart KM, van Schoor NM, Lips P. Vitamin B12, folic acid, and bone. Curr Osteoporos Rep. 2013 Sep;11(3):213-8. PMID: 23873438
  18. Dhonukshe-Rutten RA et al. Vitamin B-12 status is associated with bone mineral content and bone mineral density in frail elderly women but not in men. J Nutr. 2003 Mar;133(3):801-7. PMID: 12612156
  19. Stone KL, Bauer DC, Sellmeyer D, Cummings SR. Low serum vitamin B-12 levels are associated with increased hip bone loss in older women: a prospective study. J Clin Endocrinol Metab. 2004 Mar;89(3):1217-21. PMID: 15001613
  20. National Institutes of Health; Office of Dietary Supplements. [Internet]. U.S. Department of Health & Human Services; Vitamin B12.
  21. MedlinePlus Medical Encyclopedia: US National Library of Medicine; Vitamin B12
  22. MedlinePlus Medical Encyclopedia: US National Library of Medicine; Cyanocobalamin Injection
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