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Staging vitamin B-12 (cobalamin) status in vegetarians
1Mount Sinai Medical Center, New York City.
The American Journal of Clinical Nutrition
|May 1, 1994
Summary
Early detection of vitamin B-12 deficiency is possible by measuring vitamin B-12 bound to transcobalamin II (holoTCII). This marker indicates negative cobalamin balance before total serum vitamin B-12 levels decline, aiding in timely intervention.
Area of Science:
- Biochemistry
- Nutrition Science
- Hematology
Background:
- Vitamin B-12 (cobalamin) is essential for cellular function and DNA synthesis.
- Negative cobalamin balance progresses through distinct stages: serum, cell, biochemical, and clinical deficiency.
- Serum vitamin B-12 is transported by two proteins: transcobalamin II (TCII) and haptocorrin.
Purpose of the Study:
- To identify the earliest indicator of negative vitamin B-12 balance.
- To compare the diagnostic utility of holoTCII versus total serum vitamin B-12.
Main Methods:
- The study describes the four stages of negative vitamin B-12 balance.
- It highlights the roles of TCII and haptocorrin in vitamin B-12 transport and storage.
- The research focuses on the kinetics of holoTCII depletion.
Main Results:
- Holotranscobalamin II (holoTCII) levels decrease within days of ceasing vitamin B-12 intake.
- HoloTCII depletion precedes the decline in total serum vitamin B-12.
- Measurement of holoTCII serves as an early screening test for negative vitamin B-12 balance.
Conclusions:
- HoloTCII is a sensitive marker for detecting early negative vitamin B-12 balance.
- Measuring holoTCII allows for earlier identification of potential vitamin B-12 deficiency than total serum B-12.
- This finding supports holoTCII as a valuable tool in clinical practice for assessing vitamin B-12 status.
