Hey VMary -- Good to see you here!! Sorry to hear about the ferritin and zinc. I hope they improve soon! I wonder if the gut is involved after years of SAD/neolethal damage?
NH-- that sucks about your bosslady but great to hear the B12 reversal of symptoms with repletion and treatment. The sad thing is that even many young infants and children have B12 deficiency (e.g. 'failure to thrive' diagnoses and other types of neurodeficits) because of the current SAD diet. B12 deficiency is related to seizures and many other types of brain damage which can be irreversible later like Wernicke's in chronic alcoholics from alcohol-malnourished states.
The gut lining cells have at the tip (of the villi) many of the critical enzymes and transporters for absorption, metabolism, activation/detox for our food and nutrients, naturally, right?
Gluten and other food allergens will destroy the villi so instead of sticking 'upward' they are flattened and useless. For some it only takes 1-2 months to heal but others depending on their hormone/nutritional status, much longer, I've observed.
To grow these fundamentally essential villi back, avoidance of the food allergens (gluten/grains, dairy/casein, phyate/legumes, egg white, nightshades, nuts, whatever) is absolutely necessary. Then nutrients to heal the villi are required (vitamin D, all the fat-soluble nutrients, saturated fat, omega-3, zinc, gut-specific and immune-specific amino acids/protein (GLUTAMINE is essential, leucine, taurine, etc), B-vitamins, minerals, etc.
B12 is just a temporary bandaid.
Besides foods and lifestyles, many drugs deplete B12 (probably by a variety of gut-bacteria-displacing mechanisms)
--artifical synthetic hormones (Big Pharm 'HRT')
--prilosec (the 'purple pill' and its mirror image Nexium)
--pepsid (acid blocker and all its cousins: tagamet axid etc)
--metformin (the #1 diabetic drug)
--any stomach upsetting or acid disrupting drug