Vitamin B12: Physiology, Dietary Sources, and Requirements

Research output: Chapter in Book/Report/Conference proceedingChapter

3 Citations (Scopus)

Abstract

Vitamin B12, a cobalamin, is required for only two enzyme reactions in humans and animals: The conversion of methylmalonyl CoA to succinyl CoA and addition of a methyl group to homocysteine to form methionine. Vitamin B12 does not occur in plants, and the only natural sources are animal source foods, a low intake of which can cause deficiency. Vitamin B12 release from food and its subsequent absorption are complex processes, which can be impaired by many factors leading to depletion of body stores over time. Several laboratory tests can be used to assess vitamin B12 status but the mechanisms underlying the neurological and cognitive symptoms of deficiency are not yet understood.

Original languageEnglish (US)
Title of host publicationEncyclopedia of Human Nutrition
PublisherElsevier Inc.
Pages351-356
Number of pages6
Volume4-4
ISBN (Electronic)9780123848857
ISBN (Print)9780123750839
DOIs
StatePublished - Jan 1 2012

Fingerprint

Nutritional Requirements
Vitamin B 12
Food
Neurobehavioral Manifestations
Homocysteine
Methionine
Enzymes

Keywords

  • Anemia
  • Cobalamin
  • DNA
  • Folate
  • Haptocorrin
  • Homocysteine
  • Intrinsic factor
  • Macrocytosis
  • Megaloblastic anemia
  • Methionine
  • Methylmalonic acid
  • Myelin
  • S-adenosyl methionine
  • Transcobalamin
  • Vitamin B

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Green, R. (2012). Vitamin B12: Physiology, Dietary Sources, and Requirements. In Encyclopedia of Human Nutrition (Vol. 4-4, pp. 351-356). Elsevier Inc.. https://doi.org/10.1016/B978-0-12-375083-9.00056-8

Vitamin B12 : Physiology, Dietary Sources, and Requirements. / Green, Ralph.

Encyclopedia of Human Nutrition. Vol. 4-4 Elsevier Inc., 2012. p. 351-356.

Research output: Chapter in Book/Report/Conference proceedingChapter

Green, R 2012, Vitamin B12: Physiology, Dietary Sources, and Requirements. in Encyclopedia of Human Nutrition. vol. 4-4, Elsevier Inc., pp. 351-356. https://doi.org/10.1016/B978-0-12-375083-9.00056-8
Green R. Vitamin B12: Physiology, Dietary Sources, and Requirements. In Encyclopedia of Human Nutrition. Vol. 4-4. Elsevier Inc. 2012. p. 351-356 https://doi.org/10.1016/B978-0-12-375083-9.00056-8
Green, Ralph. / Vitamin B12 : Physiology, Dietary Sources, and Requirements. Encyclopedia of Human Nutrition. Vol. 4-4 Elsevier Inc., 2012. pp. 351-356
@inbook{a38c09b115f74a52a93af49b1f49acac,
title = "Vitamin B12: Physiology, Dietary Sources, and Requirements",
abstract = "Vitamin B12, a cobalamin, is required for only two enzyme reactions in humans and animals: The conversion of methylmalonyl CoA to succinyl CoA and addition of a methyl group to homocysteine to form methionine. Vitamin B12 does not occur in plants, and the only natural sources are animal source foods, a low intake of which can cause deficiency. Vitamin B12 release from food and its subsequent absorption are complex processes, which can be impaired by many factors leading to depletion of body stores over time. Several laboratory tests can be used to assess vitamin B12 status but the mechanisms underlying the neurological and cognitive symptoms of deficiency are not yet understood.",
keywords = "Anemia, Cobalamin, DNA, Folate, Haptocorrin, Homocysteine, Intrinsic factor, Macrocytosis, Megaloblastic anemia, Methionine, Methylmalonic acid, Myelin, S-adenosyl methionine, Transcobalamin, Vitamin B",
author = "Ralph Green",
year = "2012",
month = "1",
day = "1",
doi = "10.1016/B978-0-12-375083-9.00056-8",
language = "English (US)",
isbn = "9780123750839",
volume = "4-4",
pages = "351--356",
booktitle = "Encyclopedia of Human Nutrition",
publisher = "Elsevier Inc.",

}

TY - CHAP

T1 - Vitamin B12

T2 - Physiology, Dietary Sources, and Requirements

AU - Green, Ralph

PY - 2012/1/1

Y1 - 2012/1/1

N2 - Vitamin B12, a cobalamin, is required for only two enzyme reactions in humans and animals: The conversion of methylmalonyl CoA to succinyl CoA and addition of a methyl group to homocysteine to form methionine. Vitamin B12 does not occur in plants, and the only natural sources are animal source foods, a low intake of which can cause deficiency. Vitamin B12 release from food and its subsequent absorption are complex processes, which can be impaired by many factors leading to depletion of body stores over time. Several laboratory tests can be used to assess vitamin B12 status but the mechanisms underlying the neurological and cognitive symptoms of deficiency are not yet understood.

AB - Vitamin B12, a cobalamin, is required for only two enzyme reactions in humans and animals: The conversion of methylmalonyl CoA to succinyl CoA and addition of a methyl group to homocysteine to form methionine. Vitamin B12 does not occur in plants, and the only natural sources are animal source foods, a low intake of which can cause deficiency. Vitamin B12 release from food and its subsequent absorption are complex processes, which can be impaired by many factors leading to depletion of body stores over time. Several laboratory tests can be used to assess vitamin B12 status but the mechanisms underlying the neurological and cognitive symptoms of deficiency are not yet understood.

KW - Anemia

KW - Cobalamin

KW - DNA

KW - Folate

KW - Haptocorrin

KW - Homocysteine

KW - Intrinsic factor

KW - Macrocytosis

KW - Megaloblastic anemia

KW - Methionine

KW - Methylmalonic acid

KW - Myelin

KW - S-adenosyl methionine

KW - Transcobalamin

KW - Vitamin B

UR - http://www.scopus.com/inward/record.url?scp=85043275864&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85043275864&partnerID=8YFLogxK

U2 - 10.1016/B978-0-12-375083-9.00056-8

DO - 10.1016/B978-0-12-375083-9.00056-8

M3 - Chapter

AN - SCOPUS:85043275864

SN - 9780123750839

VL - 4-4

SP - 351

EP - 356

BT - Encyclopedia of Human Nutrition

PB - Elsevier Inc.

ER -