from the comments section
The only problem that I'm aware of with eating cambium is eating it constantly for too long will stop up your large intestine. The blockage causes serious pain. It should be fine consumed infrequently.
A warning from me as a herbalist: Please eat at the beginning VERY small quantities - like 1 spoon full twice a week ...
The microbiom can become very upset when overwrought with such high-density nutrients.