High serum levels are needed to "push" B12 into the spinal fluid and hence the brain. There are transporters or some process that carries it there. Higher blood levels, facilitate this process because of the gradient it creates. That is one goal for keeping the serum levels up.
__________________
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.