From the Guidelines
Vitamin B12, also known as cobalamin, is an essential water-soluble vitamin that plays crucial roles in nerve function, DNA synthesis, and red blood cell formation, with a recommended daily intake of approximately 2.4 micrograms for adults 1.
Key Functions and Sources
Vitamin B12 is naturally found in animal products such as meat, fish, eggs, and dairy, making it a nutrient that vegetarians and vegans may need to supplement 1. It requires a substance called intrinsic factor, produced by the stomach, for proper absorption. The vitamin is a cofactor for two enzymes in humans: methionine synthase and methyl malonyl-CoA mutase, which are essential for mitochondrial metabolism, immune response, preservation of DNA integrity, and synthesis of neurotransmitters 1.
Deficiency and Risk Factors
Deficiency can lead to serious health problems including anemia, neurological damage, fatigue, and weakness. People with certain conditions like pernicious anemia, Crohn's disease, or those who have undergone gastric surgery may require B12 supplementation 1. Additionally, individuals with a diet low in vitamin B12, certain health conditions, or taking specific medicines such as metformin or H2 receptor antagonists are at risk of deficiency 1.
Supplementation and Storage
Vitamin B12 supplementation is typically available as oral tablets (100-1000 mcg daily), sublingual formulations, or injections (1000 mcg monthly for maintenance) 1. The body can store vitamin B12 for several years, but regular intake is necessary to maintain adequate levels, especially for at-risk populations. The most recent guideline recommends considering the individual's needs, health status, and dietary habits when determining the appropriate supplementation regimen 1.
From the FDA Drug Label
Vitamin B12 is essential to growth, cell reproduction, hematopoiesis, and nucleoprotein and myelin synthesis. Vitamin B12, also known as cobalamin, is a crucial nutrient necessary for various bodily functions, including:
- Growth
- Cell reproduction
- Hematopoiesis (production of blood cells)
- Nucleoprotein and myelin synthesis 2
From the Research
Definition and Importance of Vitamin B12
- Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a crucial role in human metabolism 3, 4, 5.
- It is essential for cellular function, particularly for the nervous system, red blood cell production, and DNA synthesis 3, 5, 6.
- Vitamin B12 is synthesized only by prokaryotic organisms, and humans rely on its exogenous dietary intake 3.
Functions and Deficiency of Vitamin B12
- Vitamin B12 deficiency can lead to hematological and neurological disorders, and its manifestation can be relatively late 5.
- Deficiency of vitamin B12 is considered a significant public health issue worldwide, especially in the elderly 3.
- High levels of vitamin B12 can also indicate a risk factor for morbidity with various clinical manifestations 3, 4.
- Vitamin B12 has antioxidant properties that help protect DNA from damage caused by reactive oxygen species 6.
Forms and Treatment of Vitamin B12 Deficiency
- Vitamin B12 has two active co-enzyme forms, methylcobalamin and adenosylcobalamin, which have distinct metabolic fates and functions 7.
- Treatment of vitamin B12 deficiency can be done with a combination of methylcobalamin and adenosylcobalamin or hydroxocobalamin 7.
- Oral replacement therapy has been shown to be effective in treating vitamin B12 deficiency, in addition to intramuscular injections 4, 7.