Neurochemical, neurophysiological, and neuropathological studies in vitamin E deficiency

It is now recognized that vitamin E is essential for normal neurological structure and function in both man and experimental animals, with severe deficiency resulting in a characteristic neurological syndrome. The reasons why the neurological system should be particularly susceptible to a deficiency of this fat-soluble vitamin, and the mechanisms involved, are not known. In this review, the neurochemistry, neuropathology, and neurophysiology associated with vitamin E deficiency are described and correlated. A deficiency of vitamin E results in a "distal or dying back" axonal neuropathy which predominantly involves the centrally directed fibers of sensory neurons, with the large caliber myelinated fibers being particularly affected. Both the pathological and electrophysiological studies indicate that the primary abnormality is a degeneration of the axons which then results in a secondary demyelination. The mechanism(s) involved is assumed to involve lipid peroxidation of neuronal membranes as a consequence of a deficiency of the major lipid-soluble secondary (i.e., chain breaking) antioxidant in vivo.