Vitamins are substances that the human body requires but is unable to synthesize and therefore, must obtain externally. Deficiencies in three B vitamins, B1 or thiamine, B3 or niacin and B12 or cobalamin are known to cause neurological disorders. Thiamine deficiencies result in a disease called beriberi, which causes peripheral neurological dysfunction and cerebral neuropathy. Niacin deficiencies cause a wasting disease known as pellagra, which affects the skin, mucous membranes, gastrointestinal tract as well as the brain, spinal cord and peripheral nerves. Cobalamin deficiencies most often result in the disease pernicious anemia. Neurological symptoms of pernicious anemia include numbness in the extremities, impaired coordination and a ringing in the ears.
Thiamine was the first water-soluble vitamin to be discovered, and is therefore, also known as vitamin B1. Thiamine deficiency, or beriberi, manifests itself as both wet beriberi, which affects the cardiovascular system, and dry beriberi, which causes neurological dysfunction. People suffering from beriberi exhibit muscle atrophy or wasting (especially in the legs), edema (swelling), mental confusion, intestinal discomfort and an enlarged heart. Severe cases of dry beriberi may result in Wernicke-Korsakoff syndrome and acute cases of wet beriberi may cause shoshin beriberi. Both of these extreme forms of the disease are sometimes fatal. In most cases, administering thiamine successfully reverses symptoms associated with thiamine deficiencies.
Niacin deficiency can be treated effectively with replacement of niacin in the diet. In the case of Hartnup disease, large quantities of niacin may be required for effective reversal of symptoms.
Juli M. Berwald PhD, The Gale Group Inc., Gale, Detroit,