Hi, I realize this is a very old thread. I found this thread by looking up causes of vitamin B6 toxicity several months ago and saved it to my reading list. I too have had vitamin B6 toxicity which was discovered about two years ago by a neurologist. At that time I had what has previously been described here, neuropathy, zings down my legs (not terribly uncomfortable), feeling like pins and needles we're going down my legs, sometimes my arms. Two years ago I was taking melatonin to sleep which had B6 in it, although not enough to cause a normal person to be toxic. I stopped the melatonin and my B6 numbers came down. Then 6 months after that I saw a functional MD who put me on some supplements which had B6 in them (total of 10mg/day) and when I returned to the neurologist my B6 numbers were toxic again.
I also have celiac disease like several in this thread. Despite being on a strict GF diet, celiac disease eventually led to my having microscopic colitis(MC) specifically Collagenous colitis (to be honest, I could have had both celiac disease and MC at the same time, but didn't know that the watery diarrhea was coming from MC and maybe not celiac disease, although my celiac disease was pretty bad at the time of diagnosis.) Most doctors know very little about MC, and when one of their patients is diagnosed with MC, the doctor usually goes straight to using corticosteroids to treat the disease. But corticosteroids don't cure anything; they just mask the symptoms, and when one graduates off the corticosteroid, the symptoms usually return. So I began my detective work to try to answer some questions about why my gut is inflamed...why the colitis? I've been on a GF diet for 8 years. Long story short...I found that mast cell degradation in the gut may be causing my MC by releasing histamine into the gut. Too much histamine can cause inflammation. Why do I have too much histamine in my gut? Celiacs have trouble producing an enzyme called Diamine Oxidase (DAO) which breaks down histamine. No DAO, histamine stays in the gut to cause inflammation along with a plethora of other problems, such as painful menstral cramps, rapid heartbeat, migraine headaches, hypotension, etc. What does DAO need to breakdown histamine in our guts? Vitamin B6. And to metabolize B6 we need enough Magnesium either in our diets or through our supplementation. So, I'm wondering if I've found the answer to the B6 puzzle that seems to afflict celiacs, and those who are sensitive to gluten. I've been supplementing now with DAO, which seems to have helped my MC symptoms without my having to go on any corticosteroids. Yay!
If anyone on this thread discovered any other useful information about B6 toxicity, please post it.