From the Guidelines
Elevated vitamin B12 levels in the blood typically don't require treatment as B12 is water-soluble and excess amounts are usually excreted in urine. However, high B12 levels can be a marker for underlying conditions that warrant investigation. Common causes include liver disease, certain blood disorders like myeloproliferative neoplasms or leukemia, kidney disease, and certain cancers. Some medications can also raise B12 levels, particularly supplements containing B12 (cyanocobalamin or methylcobalamin). If you have elevated B12 without supplementation, consult your healthcare provider for appropriate evaluation, which may include liver function tests, complete blood count, and kidney function assessment.
While high B12 itself isn't typically harmful, it's essential to identify any underlying condition causing the elevation. During evaluation, continue your normal diet but avoid additional B12 supplements unless specifically directed by your healthcare provider. The body stores B12 efficiently, so levels can remain elevated for some time even after addressing the underlying cause. It's also crucial to note that folic acid supplementation may mask severe vitamin B12 depletion, as discussed in the British Obesity and Metabolic Surgery Society guidelines 1.
Key points to consider:
- Elevated B12 levels are often not harmful but may indicate underlying conditions
- Common causes of elevated B12 include liver disease, blood disorders, kidney disease, and certain cancers
- Medications, especially B12 supplements, can also raise B12 levels
- Evaluation should include liver function tests, complete blood count, and kidney function assessment
- Avoid additional B12 supplements unless directed by a healthcare provider, as folic acid supplementation may mask vitamin B12 deficiency 1.
In the context of morbidity, mortality, and quality of life, it's vital to prioritize the identification and treatment of underlying conditions that may be causing elevated B12 levels, rather than focusing solely on the elevated B12 itself. This approach is supported by the most recent and highest quality study available, which emphasizes the importance of addressing underlying conditions and avoiding unnecessary supplementation 1.
From the Research
Implications of Elevated Vitamin B12 Levels
Elevated Vitamin B12 (Cobalamin) levels, also known as hypervitaminosis B12, can have several implications, including:
- Association with oncohematological diseases, such as solid neoplasia, acute or chronic hematological diseases, and myeloid leukemia 2, 3
- Potential indicator of underlying disorders, including liver diseases, monoclonal gammapathy of undetermined significance, renal failure, inflammatory or autoimmune diseases, and transient hematological disorders 2
- Masking of underlying B12 deficiency due to complex formation of B12-vitamin binding proteins with immunoglobulins, known as macro-B12 4, 5
- Possible sign of significant morbidity, including pancreatic tumour and lung adenocarcinoma 6, 5
Underlying Causes
The underlying causes of elevated Vitamin B12 levels can be diverse, including:
- Excess of vitamin B12 intake, either through oral supplements or injections 2, 4
- Liver disorders, such as hepatitis or liver cancer 2, 3
- Hematological diseases, such as leukemia or lymphoma 2, 3
- Renal failure or kidney disease 2
- Inflammatory or autoimmune diseases, such as rheumatoid arthritis or lupus 2
- Macro-vitamin B12, a condition where vitamin B12 is bound to immunoglobulins, leading to falsely elevated cobalamin levels 4, 5
Diagnostic Considerations
When encountering elevated Vitamin B12 levels, it is essential to consider the following:
- The possibility of macro-vitamin B12, which can be distinguished from "real" high vitamin B12 using PEG precipitation 5
- The need to identify the underlying cause of hypervitaminosis B12, as it can be a sign of significant morbidity 6
- The importance of thorough medical inquiries to rule out underlying diseases, such as oncohematological disorders or liver diseases 2, 3, 5