Vitamin B12 deficiency.
Fiche publication
Date publication
juin 2017
Journal
Nature reviews. Disease primers
Auteurs
Membres identifiés du Cancéropôle Est :
Pr GUEANT Jean-Louis
Tous les auteurs :
Green R, Allen LH, Bjørke-Monsen AL, Brito A, Guéant JL, Miller JW, Molloy AM, Nexo E, Stabler S, Toh BH, Ueland PM, Yajnik C
Lien Pubmed
Résumé
Vitamin B12 (B12; also known as cobalamin) is a B vitamin that has an important role in cellular metabolism, especially in DNA synthesis, methylation and mitochondrial metabolism. Clinical B12 deficiency with classic haematological and neurological manifestations is relatively uncommon. However, subclinical deficiency affects between 2.5% and 26% of the general population depending on the definition used, although the clinical relevance is unclear. B12 deficiency can affect individuals at all ages, but most particularly elderly individuals. Infants, children, adolescents and women of reproductive age are also at high risk of deficiency in populations where dietary intake of B12-containing animal-derived foods is restricted. Deficiency is caused by either inadequate intake, inadequate bioavailability or malabsorption. Disruption of B12 transport in the blood, or impaired cellular uptake or metabolism causes an intracellular deficiency. Diagnostic biomarkers for B12 status include decreased levels of circulating total B12 and transcobalamin-bound B12, and abnormally increased levels of homocysteine and methylmalonic acid. However, the exact cut-offs to classify clinical and subclinical deficiency remain debated. Management depends on B12 supplementation, either via high-dose oral routes or via parenteral administration. This Primer describes the current knowledge surrounding B12 deficiency, and highlights improvements in diagnostic methods as well as shifting concepts about the prevalence, causes and manifestations of B12 deficiency.
Mots clés
Adolescent, Adult, Aged, Aged, 80 and over, Biomarkers, Child, Child, Preschool, Female, Homocysteine, metabolism, Humans, Male, Methylmalonic Acid, metabolism, Middle Aged, Prevalence, Risk Factors, Transcobalamins, metabolism, Vitamin B 12, blood, Vitamin B 12 Deficiency, complications, Young Adult
Référence
Nat Rev Dis Primers. 2017 Jun;3:17040