Functional cobalamin (vitamin B12) deficiency: role of advanced age and disorders associated with increased oxidative stress

Abstract

Functional Cbl deficiency is associated with disorders marked by increased oxidative stress particularly in the elderly; it occurs even when Cbl levels are high and is not consistently corrected with high-dose cyanocobalamin therapy. Thus, current approaches to recognizing and managing this disorder may be inadequate.

Single arm phase II study of oral vitamin B12 for the treatment of musculoskeletal symptoms associated with aromatase inhibitors in women with early stage breast cancer

“…The serum biomarker analyses included in this study were Serum B12, C‐reactive protein (CRP) (a nonspecific inflammatory marker), Homocysteine (HCys), and Methylmalonic Acid (MMA). HCys and MMA levels were determined to more accurately assess the vitamin B12 status . Although blood analysis may reflect levels of vitamin B12 that are in the normal range, elevated levels of cobalamin metabolites including MMA or HCys may be the first signs of deficiency .…”

“…HCys and MMA levels were determined to more accurately assess the vitamin B12 status . Although blood analysis may reflect levels of vitamin B12 that are in the normal range, elevated levels of cobalamin metabolites including MMA or HCys may be the first signs of deficiency . It has been reported that 7%‐30% of people over the age of 60 have vitamin B12 deficiency, yet their presentation is ‘subclinical’ and is known as ‘functional cobalamin deficiency’ .…”

“…17 Although blood analysis may reflect levels of vitamin B12 that are in the normal range, elevated levels of cobalamin metabolites including MMA or HCys may be the first signs of deficiency. 17 It has been reported that 7%-30% of people over the age of 60 have vitamin B12 deficiency, yet their presentation is 'subclinical' and is known as 'functional cobalamin deficiency'. 17,18 Serum studies for B12 and CRP levels included in this trial were obtained Pre-screened & approached (n=44)…”

“…17 It has been reported that 7%-30% of people over the age of 60 have vitamin B12 deficiency, yet their presentation is 'subclinical' and is known as 'functional cobalamin deficiency'. 17,18 Serum studies for B12 and CRP levels included in this trial were obtained Pre-screened & approached (n=44)…”

Vitamin B12 - physiologische ­Bedeutung und therapeutische Möglichkeiten

“…B. Cyanocobalamin 500-1000 µg/Tag) kann durch Mangel entwickeln kann. Dabei ist bemerkenswert, dass bei älteren Patienten mit einer zusätzlichen Belastung durch oxidativen Stress auch Serumspiegel von Cobalamin im höheren Normalbereich (> 800 pg/ml) nicht vor einem Anstieg von MMA und/oder Homocystein schützen können [36]. Da Cobalamin sehr oxidationsempfindlich ist, kann es durch intrazellulären oxidativen Stress inaktiviert werden.…”