Conditions That Increase B12 Levels

Some diseases can cause serum B12 levels to increase higher than normal in some people. These include kidney, liver, cancer, and duodenal ulcers (1), diabetes, obesity (2), and cyanide metabolism defects (3). B12 deficiency can be hidden by alcoholism because excess B12 is released into the blood from the damaged liver (4). There is also evidence that a bacterial overgrowth from the colon into the small intestine can lead to elevated vitamin B12 levels (5).


1. Halsted JA, Carroll J, Rubert S. Serum and tissue concentration of vitamin B12 in certain pathologic states. N Engl J Med. 1959;260:575-80.

2. Fischbach F. A Manual of Laboratory & Diagnostic Tests, 6th Ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2000.

3. Linnell JC, Matthews DM. Cobalamin metabolism and its clinical aspects. Clin Sci (Lond). 1984 Feb;66(2):113-21.

4. Herbert V. Staging vitamin B-12 (cobalamin) status in vegetarians. Am J Clin Nutr. 1994 May;59(5 Suppl):1213S-1222S.

5. Mouton, Georges. Elevated Blood Levels of Vitamin B12. Accessed May 30, 2013. | link