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 published here. Dr. Weyrich welcomes financial contributions to support specific research topics, as well as copies of non-free access journal articles for him to review on a topic. 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 [PA-OAT], [Surendran2018].

Diagnosis of Vitamin B-12 Deficiency

Symptoms of Vitamin B-12 deficiency include:

Tests include:


References for Vitamin B-12 Deficiency