Your nervous system consists of two main divisions. Your central nervous system includes your brain and spinal cord, while your peripheral nervous system is comprised of long, filamentous nerve bundles outside of your skull and spinal column. Peripheral neuropathy is a term used to describe damage to groups of nerves outside of your central nervous system. Deficiencies of certain B vitamins can cause peripheral neuropathy, but B vitamins are not effective for treating all forms of peripheral neuropathy.
Your peripheral nerves are susceptible to damage from a variety of sources, including trauma, alcohol and other toxins, medications, nutritional deficiencies, cancer, AIDS, bacterial infections, genetic conditions and metabolic disorders, such as diabetes and hypothyroidism. According to experts at Michigan State University College of Human Medicine, diabetes, hypothyroidism and nutritional deficiencies are the most common treatable causes of peripheral neuropathy.
In his book "Staying Healthy with Nutrition," Elson Haas, M.D., states that thiamin, or vitamin B-1, contributes to the health of your nerves in two ways. By contributing to the synthesis of the neurotransmitter acetylcholine, thiamin facilitates the conduction of nerve impulses through your peripheral nerves. Thiamin is also instrumental in producing myelin, which is the protective coating that insulates your nerves. Beriberi, the classic disease associated with thiamin deficiency, is characterized by burning feet, decreased reflexes, decreased sensation in your extremities and muscle weakness, all symptoms of peripheral neuropathy.
Vitamin B-12, or cobalamin, is required for the manufacture of healthy myelin. Vitamin B-12 deficiency can be caused by inefficient absorption -- a common problem in elderly people -- an autoimmune disease called pernicious anemia or a lack of dietary intake, which sometimes occurs in strict vegetarians. Numbness, tingling and a loss of vibratory sensation in your extremities are prominent symptoms of vitamin B-12-deficient peripheral neuropathy. Difficulty walking, memory loss, disorientation, paranoia and delirium can result from damage to your central nervous system.
Failure to treat peripheral neuropathies arising from nutritional deficiencies can lead to progressive nerve damage and death. Twenty to 30 mg of thiamin daily will usually address the peripheral neuropathy due to thiamin deficiency, and 1 to 2 mg of vitamin B-12 daily is typically sufficient to treat B-12 deficiency. Supplementation may need to be continued for several months or, in many cases of B-12 deficiency, for life. Many of your symptoms may reverse during therapy, but some -- particularly with vitamin B-12 deficiency -- could be permanent.
When peripheral neuropathy is due to vitamin B-1 or B-12 deficiencies, treatment with these nutrients will prevent progression and often reverse some of the damage. Peripheral neuropathies due to other causes are unlikely to respond to vitamin B-1 or B-12 supplementation. Because the causes of neuropathy are diverse -- more importantly, some are potentially life-threatening -- see your doctor to determine the cause of persistent neurologic symptoms.