Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Plant nutrition wikipedia , lookup
Wilson's disease wikipedia , lookup
Malnutrition in South Africa wikipedia , lookup
Wernicke–Korsakoff syndrome wikipedia , lookup
Human nutrition wikipedia , lookup
Alcoholic polyneuropathy wikipedia , lookup
Vitamin D deficiency wikipedia , lookup
SUPPLEMENTS Nourishing our Nerves: Neurotropic B Vitamins and Their Role in Nerve Care Overview of neurotropic B vitamins Neurotropic B vitamins are a combination of vitamins that play an important role in the health of the nervous system; they nourish and help regenerate nerves. These vitamins, thiamine (B1), pyridoxine (B6), and cobalamin (B12), are naturally obtained by eating meat, eggs, and grains.1,2 Because of the unique roles each of the neurotropic vitamins play in the health of the nervous system, all of them are essential, and a combination of all three may be needed to treat deficiencies. In an animal model, a combination of neurotropic B vitamins was found to be more effective at alleviating symptoms of neuropathy than B1, B6, or B12 given alone. 10 Deficiencies in neurotropic B vitamins Neurotropic B vitamin deficiencies occur for various reasons, such as malabsorption (e.g. post-bariatric surgery), low intake due to malnutrition or specific nutritional habits e.g. vegetarians, increased demand (e.g. pregnancy), or increased loss or malfunction associated with certain disease states (e.g. renal disease). Many conditions that cause B vitamin deficiency are chronic and/or irreversible, such as diabetes, renal impairment, gastrointestinal diseases, and advanced age. 5,11 These patients should be monitored and potentially treated as long as the condition causing B vitamin deficiency is present (e.g. long term treatment may be required). In most of these conditions, patients are deficient in all three neurotropic B vitamins – B1, B6 and B12. Symptoms of B vitamin deficiency vary. Neurological symptoms can include sensory disorders, peripheral neuropathy, polyneuritis, and weak muscle reflexes and/or coordination disorders (including gait impairment). Other possible symptoms are tiredness, hyperhomocysteinaemia, anaemia, cardiovascular dysfunction, or (in chronic deficiency) emotional disturbance. 3,5,7,12-14 In cases where B vitamin deficiency is suspected, neurotropic B vitamin supplementation is a well-tolerated approach to provide treatment. Some deficiency-related disease/ symptoms can be reversed with neurotropic B vitamin supplementation. 15 However, early diagnosis is crucial for avoiding irreversible neurological damage. 14 At therapeutic levels, neurotropic B vitamins have been shown to have a restorative effect on peripheral nerve Structure of a healthy peripheral nerve: The neurotropic B vitamins contribute to nerve health via different mechanisms. 8 SA Pharmacist’s Assistant [Winter 2016] SUPPLEMENTS Dietary sources of the neurotropic B vitamins Vitamin B1 Vitamin B6 Vitamin B12 Meat (especially pork and beef), liver, eggs, yeast, some species of fish, whole grain cereals and bread, nuts, pulses, potatoes Chicken, liver, pork and veal, fish, nuts, bread, corn and whole grain cereals Animal protein, liver, kidney, fish, eggs, dairy Vitamin Role in nerve health B1 Other contributions to health and metabolism Involved in providing energy to nerve cells, maintenance of Energy metabolism, muscle function myelin sheath which covers the axon of nerves, nerve stimulation and synthesis of neurotransmitters (acetylcholine, amino acids) 3-5 B6 Synthesis of key signalling molecules in the nervous system: neurotransmitters (epinephrine, norepinephrine, dopamine, serotonin, glycine, and gamma-aminobutyric acid [GABA]) 6-8 Carbohydrate and fat synthesis and breakdown, protein and amino acid metabolism, haemoglobin synthesis, homocysteine metabolism B12 Nerve cell maturation and regeneration, nerve cell metabolism (transmethylation processes), and formation of nerve myelin sheaths/remyelination (lipid and carbohydrate metabolism therein) 2,9 Fatty acid synthesis, nucleic acid/DNA synthesis, energy production, formation of red blood cells and maturation of other cells Vitamin Therapeutic dose Recommended daily allowance (RDA) B1 100 – 300mg (oral application) 5 1.1 – 1.2 mg 5,16 B6 50 – 600 mg (oral application) 1.3 – 1.7 mg 13,16 B12 0.2 – 2 mg (oral application) 2.0 – 2.4 μg* 9,14-16 function. 7 The levels of B vitamins present in a healthy diet do not provide these pharmacological effects and would not serve the needs of patients at risk. 6. Frye RE, Jabbour SA. Pyridoxine Deficiency. Secondary Pyridoxine Deficiency 2014. http://emedicine.medscape.com/article/124947-overview#showall. For vitamin B deficiencies associated with chronic disease or which are irreversible, long-term treatment with a pharmacological dose of neurotropic B vitamins may be required. 14 8. Dakshinamurti K, Paulose CS, Viswanathan M, et al. Neurobiology of pyridoxine. Annals of the New York Academy of Sciences 1990;585:128-44. References 11.Head KA. Peripheral neuropathy: pathogenic mechanisms and alternative therapies. Altern Med Rev 2006;11(4):294-329. 1. Watanabe T, Kaji R, Oka N, et al. Ultra-high dose methylcobalamin promotes nerve regeneration in experimental acrylamide neuropathy. Journal of the neurological sciences 1994;122(2):140-3. 12. Bernstein AL. Vitamin B6 in clinical neurology. Ann N Y Acad Sci 1990;585:250-60. 2. Zhang M, Han W, Hu S, et al. Methylcobalamin: a potential vitamin of pain killer. Neural Plast 2013;2013:424651. 3. Singleton CK, Martin PR. Molecular mechanisms of thiamine utilization. Curr Mol Med 2001;1(2):197-207. 4. Smithline HA, Donnino M, Greenblatt DJ. Pharmacokinetics of high-dose oral thiamine hydrochloride in healthy subjects. BMC Clin Pharmacol 2012;12:4. 5. Sriram K, Manzanares W, Joseph K. Thiamine in nutrition therapy. Nutr Clin Pract 2012;27(1):41-50. 10 SA Pharmacist’s Assistant [Winter 2016] 7. Reyes-Garcia G, Medina-Santillan R, Flores-Murrieta FJ, et al. Analgesic effects of B vitamins: A review. Curr Topics in Pharmacology 2006;10(1). 9. Stabler SP. Vitamin B12 deficiency. The New England journal of medicine 2013;368(21):2041-2. 10. Jolivalt CG, Mizisin LM, Nelson A, et al. B vitamins alleviate indices of neuropathic pain in diabetic rats. Eur J Pharmacol 2009;612(1-3):41-7. 13. Kjeldby IK, Fosnes GS, Ligaarden SC, et al. Vitamin B6 deficiency and diseases in elderly people--a study in nursing homes. BMC Geriatr 2013;13:13. 14. Briani C, Dalla Torre C, Citton V, et al. Cobalamin deficiency: clinical picture and radiological findings. Nutrients 2013;5(11):4521-39. 15. Woo KS, Kwok TC, Celermajer DS. Vegan diet, subnormal vitamin B-12 status and cardiovascular health. Nutrients 2014;6(8):3259-73. 16. World Health Organization, Food and Agriculture Organization of the United Nations. Vitamin and mineral requirements in human nutrition: Second edition. China, 2004.