Nutrient Guide: Vitamin B12

Essential to mental and emotional well-being, Vitamin B12 helps metabolize every cell of the body. B12 maintains healthy nerve cells, and it aids in the production of DNA and RNA, the body’s genetic material9,11,53. In addition, B12 helps regulate the formation of red blood cells and helps iron function better. Vegetarians who eat no animal products need supplemental vitamin B12 to meet their requirements 7,9,11. Carbohydrate and fat processing requires B12 for its completion, insufficiency of the vitamin can also affect the movement of carbohydrates and fats through the body 11. Vitamin B12 acts differently than other vitamins because absorption of vitamin B12 from food requires normal function of the stomach, pancreas, and small intestine as it is dependent upon intrinsic factor (IF) (protein made in the stomach) to make its way from the GI tract (stomach and intestines) into the rest of the body. Lack of stomach acids also gets in the way of B12 absorption since stomach acids are necessary to release the B12 from proteins 54,59,60. Since intrinsic factor diminishes with age, older people are more prone to B12 deficiencies. Current Reference Daily Intake (RDI)* for Vitamin B12 is 6mcg for adults and children over the age of 4 and 3mcg for children under the age of 4.

Children from macrobiotic families in the Netherlands were reported to have impaired cognitive performance 62. In these children, B12 deficiency was associated with a suboptimal performance on Raven’s CPM, which measure intelligence. Deficient schoolchildren in Guatemala had slower reaction times on psychological tests, lower academic performance, attention problems, and delinquent behavior 63. Some studies in the Western world have shown that vitamin B12 deficient infants (born to vegetarian mothers) are anemic, irritable, and anorectic and thrive poorly. These infants also have marked developmental regression and poor brain growth 64,65. No plant or animal has been shown capable of producing B12, and the exclusive source of this vitamin appears to be tiny microorganisms like bacteria, yeasts, molds, and algae 7. During infancy, signs of a vitamin B12 deficiency include failure to thrive, movement disorders, developmental delays, and megaloblastic anemia 61. Deficiencies take a long time to develop, since the body stores a three- to five-year supply in the liver 4. Low levels of B12 can cause a range of symptoms including fatigue, shortness of breath, diarrhea, nervousness, numbness, or tingling sensation in the fingers and toes. Severe deficiency causes neurological damage 11,53.nd a deficiency in Iron may lead to pernicious anemia 4,11, an autoimmune disease that results in gastric atrophy resulting in vitamin B12 malabsorption 59,60 If pernicious anemia is left untreated, it causes vitamin B12 deficiency, leading to megaloblastic anemia and neurological disorders, even in the presence of adequate dietary intake of vitamin B12 11.

Vitamin B6 is required for proper absorption of vitamin B12, and deficiency of vitamin B6 has been shown to impair B12 absorption in animal studies. Conversion of vitamin B12 from its non-active into its biologically active form requires the presence of vitamin E. Individuals at risk for vitamin E deficiency may show signs of vitamin B12 deficiency as well 7. Vitamins B12B6, and B9 work together to control blood levels of homocysteine. Numerous studies indicate that even moderately elevated levels of homocysteine in the blood increase the risk of cardiovascular diseases 57 However, researchers aren’t sure whether homocysteine is a cause of heart disease or merely a marker that indicates someone may have heart disease 58. Studies have found that as many as 30% of patients hospitalized for depression are deficient in vitamin B12, but the reasons for the relationship between vitamin B12 deficiency and depression are not clear 55Vitamin B12 and folate work together to produce S-adenosylmethionine (SAMe), which is essential in immune function and mood. Several studies have shown supplementation with SAMe improves depressive symptoms 56

Sources of Vitamin B12 

Only bacteria can synthesize vitamin B12 and it cannot be made by animals or plants. Because of their greater ability to store vitamin B12, animals contain more of the vitamin than plants. The richest sources of vitamin B12 are snapper and calf’s liver, and to a lesser extent milk. When derived from animal foods, vitamin B12 is fairly well preserved under most cooking conditions. Other good sources of vitamin B12 include venison, shrimp, scallops, salmon, and beef. Within the plant world, sea plants (like kelp), algaes (like blue-green algae), yeasts (like brewer’s yeast), and fermented plant foods (like tempeh, miso, or tofu) are the most commonly consumed food sources of vitamin B127,9

For more information on the nutrient content of foods, search the USDA food composition database.

FoodServingVitamin B12 (mcg)
Clams (steamed)3 ounces84
Mussels (steamed)3 ounces20.4
Crab (steamed)3 ounces8.8
Salmon (baked)3 ounces2.4
Rockfish (baked)3 ounces1.0
Beef (cooked)3 ounces2.1
Chicken (roasted)3 ounces0.3
Turkey (roasted)3 ounces0.3
Egg (poached)1 large0.6
Milk (skim)8 ounces0.9
Brie (cheese)1 ounce0.5

* The Reference Daily Intake (RDI) is the value of established by the Food and Drug Administration (FDA) for use in nutrition labels. It was based initially on the highest 1968 Recommended Dietary Allowance (RDA) for each nutrient, to assure that needs were met for all age groups. To see more recent recommendations, please see the Dietary Reference Intakes (DRI). These are the most recent set of dietary recommendations established by the Food and Nutrition Board of the Institute of Medicine, 1997-2001. They replace previous RDAs and may be the basis for eventually updating the RDI’s. See here for a comparison of RDIs and DRIs.

REFERENCES

  1. “B Vitamins.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 26 May 2010. Web. 29 May 2010. http://en.wikipedia.org/wiki/B_vitamins
  2. Chemistry Dictionary. A Dictionary of Chemistry. Sixth Edition. Copyright © Market House Books Ltd, 2008. All rights reserved.
  3. Alternative Medicine Encyclopedia. Encyclopedia of Alternative Medicine. Copyright © 2005 by The Gale Group, Inc. All rights reserved.
  4. Nancy Schimelpfening, “Vitamin for Depression? A Good Vitamin Supplement Could Be Just What the Doctor Ordered” About.com Guide May 04, 2009. Web.
  5. The American Cancer Society
  6. National Institutes of Health Office of Dietary Supplements
  7. The George Mateljan Foundation
  8. Food and Fitness. Food and Fitness: A Dictionary of Diet and Exercise. Copyright © 1997, 2003 by Oxford University Press. All rights reserved.
  9. The Linus Pauling Institute Micronutrient Information Center
  10. Rindi G. Thiamin. In: Ziegler EE, Filer LJ, eds. Present Knowledge in Nutrition. 7th ed. Washington D.C.: ILSI Press; 1996:160-166.
  11. Food and Nutrition Board, Institute of Medicine. Thiamin. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington D.C.: National Academy Press; 1998:58-86. (National Academy Press)
  12. Roger F. Butterworth, Thiamin Deficiency and Brain Disorders. Nutrition Research Reviews (2003), 16, 277-283 DOI: 10.1079/NRR200367
  13. Tanphaichitr V. Thiamin. In: Shils M, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore: Williams & Wilkins; 1999:381-389.
  14. “Thiamine.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 25 May 2010. Web. 29 May 2010. http://en.wikipedia.org/wiki/Thiamine
  15. National Institute of Neurological Disorders and Stroke, National Institutes of Health
  16. Chun WJ, Park LC, Uchida K, Gibson GE. “Oxidative stress is associated with region-specific neuronal death during thiamine deficiency” J Neuropathol Exp Neurol. 1999 Sep;58(9):946-58.
  17. Powers HJ. Current knowledge concerning optimum nutritional status of riboflavin, niacin and pyridoxine. Proc Nutr Soc. 1999;58(2):435-440.
  18. McCormick DB. Riboflavin. In: Shils M, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore: Williams & Wilkins; 1999:391-399.
  19. Soares MJ, Satyanarayana K, Bamji MS, Jacob CM, Ramana YV, Rao SS. The effect of exercise on the riboflavin status of adult men. Br J Nutr. 1993;69(2):541-551.
  20. Bohles H. Antioxidative vitamins in prematurely and maturely born infants. Int J Vitam Nutr Res. 1997;67(5):321-328.
  21. “Riboflavin.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 25 May 2010. Web. 29 May 2010. http://en.wikipedia.org/wiki/Riboflavin
  22. Sándor PS, Afra J, Ambrosini A, Schoenen J. Prophylactic treatment of migraine with beta-blockers and riboflavin: differential effects on the intensity dependence of auditory evoked cortical potentials. Headache. 2000 Jan;40(1):30-5.
  23. “Pantothenic acid.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 25 May 2010. Web. 29 May 2010. http://en.wikipedia.org/wiki/Pantothenic_acid
  24. Gropper, S. S, Smith, J. L., Groff, J. L. (2009). Advanced nutrition and human metabolism. Belmont, CA: Wadsworth, Cengage learning.
  25. Otten, J. J., Hellwig, J. P., Meyers, L. D. (2008). Dietary reference intakes: The essential guide to nutrient requirements. Washington, DC: The National Academies Press
  26. Hodges RE, Ohlson MA, Bean WB. Pantothenic acid deficiency in man. J Clin Invest. 1958;37:1642-1657.
  27. Weimann BI, Hermann D. Studies on wound healing: effects of calcium D-pantothenate on the migration, proliferation and protein synthesis of human dermal fibroblasts in culture. Int J Vitam Nutr Res. 1999;69(2):113-119.
  28. Gaddi A, Descovich GC, Noseda G, et al. Controlled evaluation of pantethine, a natural hypolipidemic compound, in patients with different forms of hyperlipoproteinemia. Atherosclerosis. 1984;50(1):73-83.
  29. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. National Academy Press, 2000
  30. Combs,G. F. Jr. The Vitamins: Fundamental Aspects in Nutrition and Health. 3rd Edition. Ithaca, NY: Elsevier Academic Press; 2008; pg.346
  31. Said H, Ortiz A, McCloud E, Dyer D, Moyer M, Rubin S (1998). “Biotin uptake by human colonic epithelial NCM460 cells: a carrier-mediated process shared with pantothenic acid.” Am J Physiol 275 (5 Pt 1): C1365-71. PMID 9814986.
  32. Aprahamian M, Dentinger A, Stock-Damge C, Kouassi JC, Grenier JF. Effects of supplemental pantothenic acid on wound healing: experimental study in rabbit. Am J Clin Nutr. 1985;41(3):578-89.
  33. Fidanza A. Therapeutic action of pantothenic acid. Int J Vitam Nutr Res 1983;suppl 24:53-67.
  34. Adding vitamins to the mix: skin care products that can benefit the skin [press release]. American Academy of Dermatology; March 11, 2000.
  35. Pitsavas, Stergios; Christina Andreou, Franzesca Bascialla, Vasilis P. Bozikas, Athanasios Karavatos (2004). “Pellagra Encephalopathy Following B-Complex Vitamin Treatment without Niacin”. International Journal of Psychiatry in Medicine 31 (1): 91-96.http://baywood.metapress.com/link.asp?id=29xv1gg1u17krgjh. Retrieved 2009-11-27.
  36. Prakash, Ravi; Sachin Gandotra, Lokesh Kumar Singh, Basudeb Das, Anuja Lakra. “Rapid resolution of delusional parasitosis in pellagra with niacin augmentation therapy”. General Hospital Psychiatry 30 (6): 581-584. doi:10.1016/j.genhosppsych.2008.04.011.http://www.sciencedirect.com/science/article/B6T70-4T24FKB-D/2/f619871a3d1f1d626b775c84523d6d94. Retrieved 2009-11-27.
  37. “Guidelines for Niacin Therapy For the Treatment of Elevated Lipoprotein a (Lpa)”. Rush Hemophilia & Thrombophilia Center. August 15, 2002, Revised July 27, 2005. Retrieved 20 November 2009. “facial flushing is a common side effect of niacin therapy that usually subsides after several weeks of consistent niacin use”
  38. “Niacin.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 25 May 2010. Web. 29 May 2010. http://en.wikipedia.org/wiki/Niacin
  39. Mayo Foundation for Medical Education and Research
  40. The National Library of Medicine. http://medlineplus.gov/
  41. Hageman GJ, Stierum RH. Niacin, poly(ADP-ribose) polymerase-1 and genomic stability. Mutat Res. 2001;475(1-2):45-56.
  42. Weitberg AB. Effect of nicotinic acid supplementation in vivo on oxygen radical-induced genetic damage in human lymphocytes. Mutat Res. 1989;216(4):197-201.
  43. Jacobson EL. Niacin deficiency and cancer in women. J Am Coll Nutr. 1993;12(4):412-416.
  44. Gregory JF, 3rd. Nutritional Properties and significance of vitamin glycosides. Annu Rev Nutr. 1998;18:277-296.
  45. Maureen Williams, ND. Chromium and Biotin – Natural Blood Sugar Control
  46. “Biotin.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 23 May 2010. Web. 31 May 2010. http://en.wikipedia.org/wiki/Biotin
  47. Zempleni J, Mock DM. (1999). “Biotin biochemistry and human requirements.”. J Nutr Biochem. 10 (3): 128-138. PMID 15539280.
  48. Higdon, Jane (2003). “Biotin”. An evidence-based approach to vitamins and minerals. Thieme. ISBN 9781588901248.
  49. Hansen CM, Leklem JE, Miller LT. Vitamin B-6 status of women with a constant intake of vitamin B-6 changes with three levels of dietary protein. J Nutr. 1996;126(7):1891-1901. (PubMed)
  50. Leklem JE. Vitamin B6. In: Machlin L, ed. Handbook of Vitamins. New York: Marcel Decker Inc; 1991:341-378.
  51. Leklem JE. Vitamin B6. In: Shils M, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore: Williams & Wilkins; 1999:413-422.
  52. David Gutierrez,”Vitamin B6 Deficiency Widespread Across U.S. Population, New Study Finds”August 26, 2008.
  53. University of Maryland Medical Center
  54. Shane B. Folic acid, vitamin B-12, and vitamin B-6. In: Stipanuk M, ed. Biochemical and Physiological Aspects of Human Nutrition. Philadelphia: W.B. Saunders Co.; 2000:483-518.
  55. Hutto BR. Folate and cobalamin in psychiatric illness. Compr Psychiatry. 1997;38(6):305-314. (PubMed)
  56. Williams AL, Girard C, Jui D, Sabina A, Katz DL. S-adenosylmethionine (SAMe) as treatment for depression: a systematic review. Clin Invest Med. 2005;28(3):132-139. (PubMed)
  57. Gerhard GT, Duell PB. Homocysteine and atherosclerosis. Curr Opin Lipidol. 1999;10(5):417-428. (PubMed)
  58. Booth GL, Wang EE. Preventive health care, 2000 update: screening and management of hyperhomocysteinemia for the prevention of coronary artery disease events. The Canadian Task Force on Preventive Health Care. CMAJ. 2000;163(1):21-29.
  59. Gueant JL, Safi A, Aimone-Gastin I, Rabesona H, Bronowicki J P, Plenat F, et al. Autoantibodies in pernicious anemia type I patients recognize sequence 251-256 in human intrinsic factor. Proc Assoc Am Physicians 1997;109:462-9. [PubMed abstract]
  60. Kapadia CR. Vitamin B12 in health and disease: part I-inherited disorders of function, absorption, and transport. Gastroenterologist 1995;3:329-44. [PubMed abstract]
  61. Monsen ALB, Ueland PM. Homocysteine and methylmalonic acid in diagnosis and risk assessment from infancy to adolescent. Am J Clin Nutr 2003;78:7-21. [PubMed abstract]
  62. Louwman MW, van Dusseldorp M, van de Vijver FJ, Thomas CM, Schneede J, Ueland PM, Refsum H, van Staveren WA. Signs of impaired cognitive function in adolescents with marginal cobalamin status. Am J Clin Nutr. 2000;72:762-9. [PubMed]
  63. Allen LH, Penland JG, Boy E, DeBaessa Y, Rogers LM. Cognitive and neuromotor performance of Guatemalan schoolers with deficient, marginal and normal plasma B-12. FASEB J. 1999;13:A544.
  64. Graham SM. Long-term neurologic consequences of nutritional vitamin B12 deficiency in infants. J Pediatr. 1992;121:710-4. [PubMed]
  65. Stollhoff K, Schulte FJ. Vitamin B12 and brain development. Eur J Pediatr. 1987;146:201-5. [PubMed]
  66. Bailey LB. Dietary reference intakes for folate: the debut of dietary folate equivalents. Nutr Rev. 1998;56(10):294-299. (PubMed)
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