From the Guidelines
Elevated vitamin B12 levels can be caused by various factors, including excessive supplementation, liver diseases, kidney disease, blood disorders, and certain solid tumors. The most common causes of high vitamin B12 levels include excessive supplementation, either through oral supplements, injections, or fortified foods. Medical conditions that can cause elevated B12 include liver diseases such as hepatitis, cirrhosis, and liver cancer, which impair the liver's ability to store B12 properly, as seen in a study published in the Journal of Clinical Oncology 1. Kidney disease, particularly in advanced stages, may lead to B12 accumulation due to decreased clearance. Certain blood disorders like myeloproliferative disorders, polycythemia vera, and chronic myelogenous leukemia can cause increased B12 levels due to excessive production of transport proteins. Some solid tumors, particularly those affecting the liver, kidneys, and prostate, may elevate B12 levels. Autoimmune conditions like rheumatoid arthritis and lupus can sometimes cause high B12 readings due to interference with binding proteins. Interestingly, a high B12 level doesn't necessarily mean the body is utilizing the vitamin effectively, as some conditions can cause functional B12 deficiency despite elevated blood levels. If you have unexpectedly high B12 levels without supplementation, it's essential to consult with a healthcare provider to investigate potential underlying causes, as the British Obesity and Metabolic Surgery Society guidelines suggest 1.
Some key points to consider:
- Excessive supplementation is a common cause of elevated vitamin B12 levels
- Liver diseases, kidney disease, and blood disorders can also contribute to high B12 levels
- Certain solid tumors and autoimmune conditions may also be associated with elevated B12 levels
- Functional B12 deficiency can occur despite elevated blood levels, highlighting the importance of proper diagnosis and treatment. It is crucial to prioritize the investigation of underlying causes of elevated vitamin B12 levels, as they can have significant implications for morbidity, mortality, and quality of life.
From the Research
Causes of Elevated Vitamin B12 Levels
Elevated vitamin B12 levels can be caused by various factors, including:
- Hepatic diseases or tumors, as high plasma concentration of vitamin B12 was associated with interstitial renal diseases, cirrhosis, hepatitis, and liver metastasis 2
- Malignant hematologic diseases, such as lymphoma, and other types of cancer, as elevated B12 levels were linked to an increased risk of cancer 3
- Liver disease, as patients with acute-on-chronic liver failure had significantly higher B12 levels, and elevated B12 levels were associated with increased severity of liver disease and mortality 4
- Other medical conditions, such as renal disease, as high concentration of vitamin B12 was associated with interstitial renal diseases 2
Association with Mortality
While some studies suggest that elevated vitamin B12 levels may be associated with increased mortality, others have found that this association may be due to underlying liver disease or other confounding factors:
- Elevated B12 levels were associated with increased 3-month mortality rate in patients with acute-on-chronic liver failure 4
- However, after adjusting for liver function, no significant association existed between B12 and mortality in ICU patients 5
- The evidence linking vitamin B12 and mortality is less consistent, and more research is needed to fully understand this relationship 3
Other Factors
Other factors that may contribute to elevated vitamin B12 levels include:
- Metformin therapy, as long-term and high-dose metformin therapy has been associated with impaired vitamin B12 status and increased risk of vitamin B12 deficiency 6