Vitamin B 12 in Relation to Oxidative Stress: A Systematic Review

• Published in: Nutrients Vol. 11; no. 2
• Main Authors: van de Lagemaat, Erik E, de Groot, Lisette C P G M, van den Heuvel, Ellen G H M
• Format: Journal Article
• Language: English
• Published: Switzerland 01.02.2019
• Subjects: Antioxidants - metabolism; Antioxidants - pharmacology; Biomarkers; Humans; Oxidative Stress; Reactive Oxygen Species; Vitamin B 12 - metabolism; Vitamin B 12 - pharmacology; Vitamin B Complex - administration & dosage; Vitamin B Complex - pharmacology; age-related diseases; antioxidant; B12; cobalamin; subclinical deficiency; deficiency; ROS; micronutrients; triage theory; oxidative stress
• ISSN: 2072-6643
• DOI: 10.3390/nu11020482

The triage theory posits that modest micronutrient deficiencies may induce reallocation of nutrients to processes necessary for immediate survival at the expense of long-term health. Neglected processes could in time contribute to the onset of age-related diseases, in which oxidative stress is believed to be a major factor. Vitamin B (B12) appears to possess antioxidant properties. This review aims to summarise the potential antioxidant mechanisms of B12 and investigate B12 status in relation to oxidative stress markers. A systematic query-based search of PubMed was performed to identify eligible publications. The potential antioxidant properties of B12 include: (1) direct scavenging of reactive oxygen species (ROS), particularly superoxide; (2) indirect stimulation of ROS scavenging by preservation of glutathione; (3) modulation of cytokine and growth factor production to offer protection from immune response-induced oxidative stress; (4) reduction of homocysteine-induced oxidative stress; and (5) reduction of oxidative stress caused by advanced glycation end products. Some evidence appears to suggest that lower B12 status is related to increased pro-oxidant and decreased antioxidant status, both overall and for subclinically deficient individuals compared to those with normal B12 status. However, there is a lack of randomised controlled trials and prospective studies focusing specifically on the relation between B12 and oxidative stress in humans, resulting in a low strength of evidence. Further work is warranted.