Abstract
The biosynthesis of B12, involving up to 30 different enzyme-mediated steps, only occurs in bacteria. Thus, most eukaryotes require an external source of B12, and yet the vitamin appears to have only two functions in eukaryotes: as a cofactor for the enzymes methionine synthase and methylmalonylCoA mutase. These two functions are crucial for normal health in humans, and in particular, the formation of methionine is essential for providing methyl groups for over 100 methylation processes. Interference with the methionine synthase reaction not only depletes the body of methyl groups but also leads to the accumulation of homocysteine, a risk factor for many diseases. The syndrome pernicious anemia, characterized by lack of intrinsic factor, leads to a severe, sometimes fatal form of B12 deficiency. However, there is no sharp cutoff for B12 deficiency; rather, there is a continuous inverse relationship between serum B12 and a variety of undesirable outcomes, including neural tube defects, stroke, and dementia. The brain is particularly vulnerable; in children, inadequate B12 stunts brain and intellectual development. Suboptimal B12 status (serum B12<300pmol/L) is very common, occurring in 30%-60% of the population, in particular in...Continue Reading
Citations
Feb 15, 2019·Journal of Inherited Metabolic Disease·Martina Huemer, Matthias R Baumgartner
Mar 8, 2019·International Journal of Food Sciences and Nutrition·Maria V Chandra-HioeJayashree Arcot
Jul 25, 2019·JAMA Psychiatry·Babak HooshmandLaura Fratiglioni
Nov 22, 2019·European Journal of Clinical Pharmacology·Yun ZhangYehuan Sun
Jan 11, 2020·Proceedings of the National Academy of Sciences of the United States of America·Montserrat Elías-Arnanz
Jan 15, 2020·BMC Medical Genetics·Suelen Porto BasgaluppIda Vanessa Doederlein Schwartz
Jul 3, 2020·Nutrients·Joseph BoachiePonnusamy Saravanan
Jan 24, 2019·BMJ Open·Shamon AhmedJ David Spence
Dec 26, 2018·Critical Reviews in Food Science and Nutrition·Uwe GröberKlaus Kisters
Jan 17, 2019·International Journal of Molecular Sciences·Gustavo C RománCamilo Bernal
Apr 26, 2019·Metallomics : Integrated Biometal Science·Yan ZhangYinzhen Xu
Aug 7, 2020·Foods·Tatiana Pintado, Gonzalo Delgado-Pando
Jul 11, 2019·Nutrients·Jinous SamavatMichaela Luconi
Jul 25, 2019·Frontiers in Microbiology·Chong XieKati Katina
Jul 30, 2020·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·Yan Zhang, Junge Zheng
Jul 19, 2018·Pediatric Research·A David Smith
Mar 3, 2020·Journal of Nutritional Science and Vitaminology·Ke ChenChangqi Liu
Oct 9, 2020·Cell Proliferation·Yang OuyangShengrong Sun
Oct 10, 2020·BMC Medicine·Bruce H R WolffenbuttelRijk O B Gans
Jan 8, 2020·Heliyon·Maria V Chandra-HioeJayashree Arcot
Apr 4, 2021·International Journal of Molecular Sciences·Joseph BoachiePonnusamy Saravanan
Mar 5, 2021·Journal of Internal Medicine·A D Smith, H Refsum
Jul 3, 2021·Nutrients·Alessandra VincentiHellas Cena
Jul 3, 2021·Antioxidants·Arif AndraYukinori Yabuta
Jul 1, 2021·Food and Nutrition Bulletin·Chittaranjan YajnikSanat Phatak
Jul 23, 2021·Molecular Nutrition & Food Research·Pauline MoscaNatacha Dreumont