Yes, basically if you get that low there is only one reason...
failure of intrinsic factor.
Readings in the 800's are not that bad. Sometimes the real answer eludes us. Just do what you need to do. I think 5mg daily is plenty, for most people.
See what happens over 3 or so months.
__________________
All truths are easy to understand once they are discovered; the point is to discover them.-- Galileo Galilei
************************************
.
Weezie looking at petunias 8.25.2017
****************************
These forums are for mutual support and information sharing only. The forums are not a substitute for medical advice, diagnosis or treatment provided by a qualified health care provider. Always consult your doctor before trying anything you read here.