While vitamin<unk>  is water-soluble, it has a half-life of 25–33 days and accumulates in the body where it is stored in muscle, plasma, the liver, red blood cells and bound to proteins in tissues. Potential mechanisms The common supplemental form of vitamin<unk> , pyridoxine, is similar to pyridine which can be neurotoxic. Pyridoxine has limited transport across the blood–brain barrier explaining why the central nervous system is spared. Cell bodies of motor fibers are located within the spinal cord that is also restricted by the blood-brain barrier explaining why motor impairment is rare. The dorsal root ganglia, however, are located outside of the blood-brain barrier making them more susceptible. Pyridoxine is converted to pyridoxal phosphate via two enzymes, pyridoxal kinase and pyridoxine 5′-phosphate oxidase. High levels of pyridoxine can inhibit these enzymes. As pyridoxal phosphate is the active form of vitamin<unk> , this saturation of pyridoxine could mimic a deficiency of vitamin<unk> .
Megavitamin-B6 syndrome
Mercury poisoning
Zinc toxicity
Lead poisoning
Iron poisoning
Copper toxicity
Mercury Poisoning
Chromium toxicity