Normal b12 numbers
Pro Research Analysisby 
Searched over 200M research papers
Normal Vitamin B12 Levels: A Comprehensive Overview
Introduction to Vitamin B12 Levels
Vitamin B12, also known as cobalamin, is essential for various bodily functions, including DNA synthesis, red blood cell formation, and neurological function. Understanding the normal range of vitamin B12 levels is crucial for diagnosing deficiencies and ensuring optimal health.
Normal Vitamin B12 Levels in Different Populations
General Population
The normal range of serum vitamin B12 levels can vary significantly across different populations and age groups. In a study conducted in Konya, Turkey, the normal reference levels for vitamin B12 were found to be 127-606 pg/mL for girls, 127-576 pg/mL for boys, and 127-590 pg/mL for the entire study group aged 0-24 years. Another study in an industrial and agricultural community showed that the serum vitamin B12 concentration decreases with age, with adjusted means of 255.2 ± 5.45 µg/mL for industrial men and 262 ± 10.06 µg/mL for women.
Elderly Population
Vitamin B12 levels tend to decrease with age. In a study of elderly individuals from urban low-income households, serum vitamin B12 levels ranged from 226 to 1200 pg/mL, with a mean of 700 ± 191 pg/mL. Another study found that low serum B12 levels were common in an elderly subpopulation, with 26 out of 378 patients showing low levels despite being hematologically normal.
Diabetic Population
Individuals with type 2 diabetes, especially those on metformin, are at a higher risk of vitamin B12 deficiency. A study in southwestern Colombia found that the prevalence of B12 deficiency was significantly higher in individuals with type 2 diabetes compared to those without, particularly among those receiving high doses of metformin.
Methods of Measuring Vitamin B12 Levels
Different methods for measuring vitamin B12 levels can yield varying results. A comparison of three methods—radioisotopic, Euglena gracilis, and Lactobacillus leichmannii—showed that the radioisotopic assay generally gave higher results, while the Euglena gracilis assay provided the clearest distinction between normal subjects and patients with untreated pernicious anemia.
Clinical Implications of Vitamin B12 Levels
Deficiency and Borderline Levels
Vitamin B12 deficiency is typically defined as levels below 200 pg/mL, while borderline levels range from 200-299 pg/mL. Levels above 300 pg/mL are considered normal. Deficiency can lead to serious health issues, including megaloblastic anemia and neurological disorders. Even individuals with normal blood counts can have hidden vitamin B12 deficiency, which underscores the importance of awareness and early detection.
Supplementation and Treatment
Vitamin B12 supplementation can significantly improve health outcomes in deficient individuals. A study on diabetic neuropathy patients showed that oral supplementation with 1000 µg/day of methylcobalamin for one year increased plasma B12 levels and improved neurophysiological parameters, pain scores, and quality of life.
Conclusion
Normal vitamin B12 levels can vary widely depending on age, population, and health status. Understanding these variations is crucial for accurate diagnosis and effective treatment of vitamin B12 deficiency. Regular monitoring and appropriate supplementation can help maintain optimal health and prevent the adverse effects associated with deficiency.
Sources and full results
Most relevant research papers on this topic