For me I have all sorts of symptoms from insufficient vitamin D when it gets below 50 (30-100) or so, the bottom third of the range approximately. It caused most cell making to cease and I was very damaged. I bought a UVB lamp and healing has started up strongly and I had to increase methylfolate from 45 mg to 60 mg (4 doses a day) and it looks like I'm back on the refeeding syndrome merry-go-round. With low vit D I couldn't sleep well or long, poorly for about 2 hours a night. he I restarted testosterone it help considerably and now with the UVB light making vit D I am feeling lots better and healing well.
Lack of sufficient MeCbl, AdoCbl and methylfolate, among other things can decrease methylation as can lack of vit D. This can cause hundreds of symptoms and lacks and symptoms all sorts of tings.
what measuring units are you referring to? ng/ml? nmol?
i have the feeling that methylfolate wrecks me badly, the inactive folic acid though does nothing.
regarding vitamin D i have a strange thing going on. i cannot tolerate daily dosages but weekly seams ok. 7x5k makes me more and more bad (muscles cramping and pain) but once 35k is ok.
i had deficiency few month ago, it was like 4ng/ml. i could not take magnesium anymore, made me worse, but since i am back up VD by 500.000ie over the last 4 month, i think i tolerate magnesium better again. so i take every few days 100mg magnesium.
also i noticed on a course of 1-2x weekly high dose active and methylated b-complex that my asthma/allergies/food intolerances are getting worse and worse. usually VD helps me with asthma but not in combo ... or the b vitamins make asthma worse than VD makes it better. i have no such problems with VD alone, or carnitine.
VC worsens asthma as well. not from fruits though, sadly i cannot eat any fruits.
in general i take once a week like 35k VD, high dose active and "methylated" B-complex, carnitine-fumerate, B12 1-2mg, VC, VA, Omega3 ... but not anymore. because of worsening of asthma.
i am now thinking to go with methylfree b-complex and folic acid instead.