I have Pernicious Anaemia had it now quite a few years and i have a B12 jab every 3mths but i always know when i'm due, i go so tied on my legs, then my body starts plus i sleep more but with anaemia folic acid in the body is very important i have to take a tablet daily as it substitutes for many main issues.
www.umm.edu/health/medical/altmed/supplement/vitamin-b9-folic-acidTerry