Dr. Weyrich's Naturopathic Functional Medicine Notebook is a collection of information on topics of interest
to Dr. Weyrich that may be of interest to the world wide audience.
Due to limitations of time, not all information that Dr. Weyrich knows or would like to further research is
Dr. Weyrich welcomes financial contributions to support specific research topics, as well as copies of
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Constructive criticism is also welcome.
Etiology of Vitamin B-12 Deficiency
Deficiency may be due to:
Defective B-12 absorption, e.g. in pernicious anemia or certain drug therapies that cause
low intrinsic factor production.
Bacterial overgrowth of the GI tract that uses up vitamin B-12 [GP].
Genetic mutations in B-12 transporter proteins may result in a functional
intracellular deficiency of B-12, despite adequate serum levels of B-12