Vitamin B12

Do vegans need supplementation?

Vitamin B12 is essential for amino-acid metabolism and the synthesis of DNA, red blood cells, phospholipids, protein, and fatty acids (Neumann, C., Harris, D.M., and Rogers, L.M., 2002). While vitamin B12 is almost exclusively derived from animal products, fermented foods can provide variable amounts (Leung et al., 2001). However, for vegans who do not consume considerable amounts of fermented food and drink, supplements should be taken weekly or bi-weekly.


Recommended Dosage

Vitamin B12 is water-soluble, meaning any excess will be eliminated in your urine (your body's mechanism of preventing an overdose). The amount needed to prevent deficiency depends on your age (and also varies if pregnant or lactating) (see Table 1). However, your body also stores substantial amounts of B12, providing enough to last 1-2 years before suffering from deficiency.Daily supplementation is therefore unnecessary. However, frequency recommendations vary. While some physicians propose once a week supplementation (Greger, 2011), others advise every other day. Regardless, missing a few days of your supplement regime will not harm you. While B12 is absolutely essential, your body does a pretty remarkable job providing a back-up.

If vegan diets require B12 supplementation, does that make a vegan diet "unnatural?"

Although most dietary B12 is derived from animal products, this is not because animals manufacture it. It is actually the bacteria living within the animal's intestines responsible for its production. [We also harbor the same bacteria! But its location within the human body prevents its byproducts - B12 - from getting absorbed (Herbert, 1988).] These bacteria also reside in soil, clinging to carrots, beet root and rutabagas, mixing with water in our rivers - however in the 21st century, this soil is vigorously removed from our water and food before it is consumed. Water and vegetable sources that once provided B12 have been stripped through an intense purification processes. To summarize this effect, Colin Campbell characterized B12 supplements as "separation from nature" pills, demonstrating how our relatively recent dietary habits have altered the nutritive profile of our food. Humans are now forced to use animal foods or supplementation to prevent vitamin B12 deficiency (Campbell and Campbell, 2006).

Vitamin B12 & Childhood Deficiency

Once solid foods are introduced to a child's diet, recommendations for vegan (and                   ) children closely mimic adult guidelines. Vitamin B12 should be consumed through supplementation, fortification or fermented foods (Jacobs and Dwyer, 1988). As supplements are highly absorbable, children do not risk deficiency when they are routinely consumed (Sanders,1988; Dwyer et al.,1982).

Food preferences (e.g. consumption of fermented foods) may influence vitamin B12 intake, altering the cultural applicability of these recommendations (Leung et al., 2000, Goraya, Kaur and Mehra, 2015). However, due to the crippling effects of vitamin B12 deficiency, all vegan children should receive medical observation to monitor B12 consumption.


                              children do not run a heightened risk of deficiency and therefore have no need for supplementation (Dwyer et al., 1982, Thane and Bates, 2000, Leung et al., 2001).

(The Natural Standard Research Collaboration, 2013)

Vitamin B12, Pregnancy, and Lactation

Newborns store enough vitamin B12 to sustain the first 4-12 months of life, given their mothers consumed adequate levels of vitamin B12 during pregnancy and/or did not suffer from malabsorption (malabsorbtion typically results from intestinal parasitic infections or anemia) (Black, 2008). Research suggests that a breastfeeding mother with a vegan (or                  ) diet should take vitamin B12 supplementation to avoid infantile deficiency, which can cause stunted growth, developmental regression, neurological damage, apathy, irritability, and anorexia (Abu-Kishk et al., 2009, Goraya, Kaur and Mehra, 2015, Akcaboy et al., 2015). Vitamin treatment throughout infancy improves these symptoms, but long-term brain damage persists (Von Schenck, Bender-Götze and Koletzko, 1997, Baatenburg de Jong et al., 2005, Abu-Kishk et al., 2009, Louwman et al., 2000).

Vitamin B12 supplementation is also recommended for 

and                               mothers who lack access to dairy products (Goraya, Kaur and Mehra, 2015, Akcaboy et al., 2015, Abu-Kishk et al., 2009). 



  1. Neumann, C., Harris, D.M., and Rogers, L.M. (2002). Contribution of animal source foods in improving diet quality and function in children in the developing world. Nutrition Research. 22 (1), 193-220.

  2.  Leung, S. et al. (2001). Growth and nutrition of Chinese vegetarian children in Hong Kong. Journal of Paediatrics and Child Health. 37 (3), 247-253.

  3.  Hebert, J.R. (1985). Relationship of vegetarianism to child growth in South India. The American Journal of Clinical Nutrition. 42 (6), 1246-1254.

  4. Campbell, T.C. and Campbell, T.M. (2006). The china study. Dallas: BenBella Books.

  5.  Black, M.M. (2008). Effects of vitamin B12 and folate deficiency on brain development in children. Food and Nutrition Bulletin. 29 (2 suppl1), S131.

  6.  Abu-Kishk, I. et al. (2009). Infantile encephalopathy due to vitamin deficiency in industrial countries. Child's Nervous System. 25 (11), 1477-1480.

  7.  Goraya, J.S., Kaur, S., and Mehra, B. (2015). Neurology of Nutritional Vitamin B12 Deficiency in Infants: Case Series From India and Literature Review. Journal of Child Neurology. 0883073815583688.

  8.  Akcaboy, M. et al. (2015). Vitamin B12 deficiency in infants. The Indian Journal of Pediatrics. 82 (7), 619-624.

  9.  Von Schenck, U., Bender-Götze, C., and Koletzko, B. (1997). Persistence of neurological damage induced by dietary vitamin B-12 deficiency in infancy. Archives of Disease in Childhood. 77 (2), 137-139.

  10.  Baatenburg de Jong, R. et al. (2005). Severe nutritional vitamin deficiency in a breast-fed infant of a vegan mother. European Journal of Pediatrics. 164 (4), 259-260.

  11.  Louwman, M.W. et al. (2000). Signs of impaired cognitive function in adolescents with marginal cobalamin status. The American Journal of Clinical Nutrition. 72 (3), 762-769.

  12.  Jacobs, C. and Dwyer, J.T. (1988). Vegetarian children: appropriate and inappropriate diets. The American Journal of Clinical Nutrition. 48 (3), 811-818.

  13.  Sanders, T.A.(1988). Growth and development of British vegan children. The American Journal of Clinical Nutrition. 48 (3), 822-825.

  14.  Dwyer, J.T. et al. (1982). Nutritional status of vegetarian children. The American Journal of Clinical Nutrition. 35 (2), 204-216.

  15.  Dwyer, J.T. et al. (1983). Growth in" new" vegetarian preschool children using the Jenss-Bayley curve fitting technique. The American Journal of Clinical Nutrition. 37 (5), 815-827.

  16.  Thane, C.W. and Bates, C.J. (2000). Dietary intakes and nutrient status of vegetarian preschool children from a British national survey. Journal of Human Nutrition and Dietetics. 13 (3), 149-162.

  17. Herbert, V. (1988). Vitamin B-12: plant sources, requirements, and assay. The American Journal of Clinical Nutrition, 48(3), 852-858.

  18. The Natural Standard Research Collaboration (2013). Drugs and Supplements: Vitamin B12. The Mayo Clinic. Available from [Accessed 20 September, 2017].