B6 (Pyridoxine) DESCRIPTION: Vitamin B6 is a well-known member of the water-soluble B vitamins. Besides pyridoxine, two other variations on B6 exist - namely pyridoxal and pyridoxamine. All three forms exist routinely in animal and plant foods and have equal vitamin B6 activity. STABILITY Vitamin B6 is fairly resistant to heat but may leach out into water and is also lost by exposure to alkalis or ultraviolet light. FUNCTIONS Vitamin B6 is rapidly converted in the body to the coenzymes pyridoxal phosphate and pyridoxamine phosphate. These coenzymes play an essential role in protein metabolism and also function in energy production, fat metabolism, central nervous system activity and haemoglobin production. Involved in the conversion of Essential Fatty Acids to prostaglandins, which help regulate hormone balance. It helps to stablisise fluid levels through Potassium/Sodium balance. Back to Top   DEFICIENCY The administration of a vitamin B6 antagonist to the diet of human volunteers produced symptoms of seborrhoea (oily Skin with crusts and scales) around the eyes, nose and mouth. There was also a lowering of white blood cell count and a loss of ability to convert tryptophan to nicotinic acid. A type of Anaemia was also noted. Back to Top   REQUIREMENTS Upper safe level for daily supplementation = 200mg Recommended Daily Allowance = 2mg Individuals with high intakes of protein will need more vitamin B6 in the diet. Back to Top   SUPPLEMENTAL USES The Pill and HRT: Many women on the contraceptive pill find vitamin B6 is a useful supplement to take as it can help alleviate the Depression sometimes associated with taking this medication (1). Drinkers and Smokers: People who smoke or drink large quantities of alcohol would benefit from a supplement of vitamin B6 as these activities deplete the nutrient (2). PMS: Supplemental vitamin B6 can also be useful in the treatment of Pre-menstrual syndrome (3) and is used by many women for this purpose. Studies in this area have conflicting results, but 50-200 mg daily does seem to be generally of benefit. Sickness: Vitamin B6 has been used for the prevention and treatment of nausea and Vomiting due to morning sickness (4) irradiation, drug therapy, anaesthesia and travel sickness, but a good response is not always seen. Back to Top   SAFETY 2-7g vitamin B6 daily may bring about the development of sensory neuropathy (numbness and tingling of nerves in the extremities). Such symptoms have also been reported in women taking as low as 50mg daily, but these reports have since largely been discredited. All cases of peripheral neuropathy disappeared within six months on withdrawal of the vitamin. Back to Top   INTERACTIONS AND CONTRA-INDICATIONS Levadopa: Vitamin B6 is not compatible with this medication for Parkinson’s disease. Phenytoin and Phenobarbitone: These anticonvulsant medicines should not be used in conjunction with vitamin B6. It is usually recognised that B vitamins are best taken together for most general purposes. However, there is no detriment in taking vitamin B6 singly for a specific reason. Back to Top   FOOD SOURCES Food (mg/100g) Wheatgerm 0.95 Bananas 0.51 Turkey 0.44 Chicken 0.29 Fish, white 0.29 Brussels sprouts 0.28 Beef, stewing steak 0.27 Potatoes 0.25 Baked beans 0.12 Bread, wholemeal 0.12 Peas, frozen 0.10 Bread, white 0.07 Oranges 0.06 Milk 0.06 The main sources of vitamin B6 in the diet are potatoes and other vegetables, milk and meat. REFERENCES: 1. Villegas Salas E. et al, Effect of vitamin B6 on the side effects of a low-dose combined oral contraceptive. Contraception, ,55;4:245-248, 1997. 2, Fonda ML, Vitamin B6 metabolism and binding to proteins in the blood of alcoholic and nonalcoholic men. Alcohol Clin Exp Res,17;6:1171-1178, 1993. 3. Campbell EM et al, Premenstrual symptoms in general practice patients. Prevalence and treatment. J Reprod Med,42;10:637-646, 1997. 4. Erick M, Vitamin B-6 and Ginger in morning sickness. J Am Diet Assoc, 95;4:416, 1995. 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