B12 levels and frailty syndrome

Abstract Vitamin B12, widely known as cobalamin, is a water-soluble vitamin crucial for human metabolism. It is synthesized only by prokaryotic organisms and since humans do not have the ability to synthesize it, they rely on its exogenous dietary intake. After its consumption, vitamin B12 undergoes a complicated procedure of absorption and assimilation and it is essential for cellular function, especially for nervous system, red blood cell production and DNA synthesis. Deficiency of vitamin B12 is considered as an important public health issue worldwide, while it is common in the elderly. Deficiency of this vitamin, as well as high levels, indicate a risk factor for morbidity with various clinical manifestations. Frailty is an age-related syndrome, which affects the elderly and is characterized by decreased function in many physiological systems, accompanied by vulnerability to stressors. A narrative non-systematic mini review of the literature was conducted and highlighted that vitamin B12 levels may have an impact on frailty and vice versa. As shown in several studies, vitamin B12 levels may be related to sarcopenia, cognitive and musculoskeletal disorders, neurological or psychiatric symptoms, which are closely linked to frailty. Furthermore, it is suggested that the extensions of frailty may affect the bioavailability of vitamin B12.