Here are some patient organizations and websites with possible answers to your questions. 

http://stichtingb12tekort.nl

Stichting B12 tekort (B12 deficiency Foundation) was founded in 2007 and has a website and an online forum with over 8400 members. B12 tekort is expertly led by Petra Visser. Its clear and transparent website provides scientifically based information. The forum is staffed by volunteers, who will assist you in finding information.

https://www.facebook.com/groups/807408932663995 

Facebookpage ‘B12 tekort, de vergeten ziekte’ has been run since 2015 and has over 16.000 followers. It is a private information platform, easy to use and easily accessible with committed managers who offer information and advice. They do not offer personal treatment advice.

We know from experience that no two patients are the same and every patient benefits from customized treatment. Unfortunately, some patients take supplements or stop taking them on the advice from others, with sometimes negative consequences. You should always discuss advice like this with your consulting doctor.

B12 Institute has no involvement with or control over patient group activities. They have their own policies.

© 2019, B12 Research Institute, Rotterdam