Vitamin B6 supplements

On supplementing SeMet, GSH-Px activities reach a maximum value and then plateau, while tissue Se levels continue to rise in proportion to the dosage (Deagen et al, 1987). The release of Se from SeMet also depends on vitamin B6 status. In rats maintained on a feed supplemented with 0.25 mg Se/kg of diet in the form of SeMet, GSH-Px activities in erythrocytes, muscle and heart were lower in vitamin B6-deficient than in vitamin B6-supplemented animals (Yin et al, 1996). Vitamin B6 also significantly reduced lipid peroxide contents in tissues. These results indicate that dietary vitamin B6 is involved in the metabolic breakdown of SeMet. 

Levodopa. The absorption of levodopa is decreased by iron preparations, while the effects of levodopa may be reduced or abolished by vitamin B6 supplements providing more than 5 mg daily. If the intake of vitamin B6 supplements cannot be discontinued, substitute co-careldopa or co-beneldopa for levodopa. 

Vitamin B6 deficiency diseases are very rare. In 1954, a batch of commercially prepared baby food was overheated during its preparation. Overheating apparently destroyed the vitamin B6 present in the food. Babies who were fed with the food had convulsions became unusually irritable, and developed unusual behaviors. As soon as the babies were given vitamin B6 supplements, these symptoms disappeared. Such instances among humans are so rare that they become the... 

Bryan, J., Calvaresi, E, and Hughes, D., 2002. Short-term folate, vitamin B12, or vitamin B6 supplementation slightly affects memory performance but not mood in women of various ages. The Journal of Nutrition. 132 1345-1356. 

If your patient with parkinsonism is taking levodopa, he must be careful to avoid vitamin B6 (pyridoxine) because it may interfere with the therapeutic effects of the drug. Most multivitamin supplements contain vitamin B6. Therefore, be sure to instruct your patient to check with his health care provider before taking any vitamin supplements. 

Elevated homocysteine concentrations have been associated with an increased risk for cardiovascular disease in both epidemiologic and clinical studies.43 Several studies have evaluated the benefit of lowering homocysteine levels with folic acid supplementation. One study reported a reduction in major cardiac events with the combination of folic acid, vitamin B12, and vitamin B6 following PCI.44 However, a more recent study found an increased risk of instent restenosis and the need for target-vessel revascularization with folate supplementation following coronary stent placement.45 The role of folate in the management of IHD is currently unclear. 

Prognosis is more favorable in the pyridoxine-respon-sive patients. Patients who respond to large doses of vitamin B6 (250-500 mg/day for several weeks) have the best prognosis. Efficacy of treatment usually is reflected in a reduction of blood homocystine and methionine to normal or near-normal levels. Since supplementation with pyridoxine can cause a deficiency of folic acid, the latter should be given (2-5 mg daily) at the same time. Any patient receiving pyridoxine should be monitored carefully for any signs of hepatotoxicity and for a peripheral neuropathy (see Ch. 36). 

Supplemental doses of pyridoxine hydrochloride (vitamin B6), 50 mg/ day, are recommended to prevent the peripheral neuropathy associated with isoniazid administration. 

Pyridoxine [Vitamin B ] [Vitamin B Supplement] U e Rx prevention of vit B6 deficiency Action Vit supl Dose Adults. Deficiency 10-20 mg/d PO Drug-induced neuritis 100-200 mg/d 25-100 mg/d prophylaxis Peds. 5-25 mg/d x 3 wk Caution [A (C if doses exceed RDA), +] Contra Component aUCTgy Disp Tabs 25, 50, 100 mg inj 100 mg/mL SE Allergic Rxns, HA, N Interactions -1- Effects OF levodopa, phenobarbital, phenytoin EMS Can be used as an antidote for isoniazid poisoning OD May cause sensory nerve damage (numbness, tingling, reduced sensation) and coordination problems Sxs are usually revised aft stopping pyridoxine symptomatic and supportive... 

The homocystinurias are a group of disorders involving defects in the metabolism of homocysteine. The diseases are inherited as autosomal recessive illnesses, characterized by high plasma and urinary levels of homocysteine and methionine and low levels of cysteine. The most common cause of homocystinuria is a defect in the enzyme cystathionine /3-synthase, which converts homocysteine to cystathionine (Figure 20.21). Individuals who are homozygous for cystathionine [3-synthase deficiency exhibit ectopia lentis (displace ment of the lens of the eye), skeletal abnormalities, premature arte rial disease, osteoporosis, and mental retardation. Patients can be responsive or non-responsive to oral administration of pyridoxine (vitamin B6)—a cofactor of cystathionine [3-synthase. Bg-responsive patients usually have a milder and later onset of clinical symptoms compared with B6-non-responsive patients. Treatment includes restriction of methionine intake and supplementation with vitamins Bg, B, and folate. 

Isoniazid (isonicotinic acid hydrazide), a drug frequently used to treat tuberculosis, can induce a B6 deficiency by forming an iiactive derivative with pyridoxal phosphate. Dietary supplementation with B is, thus, an adjunct to isoniazide treatment. Otherwise, cletary deficiencies in pyridoxine are rare but have been observed in newborn infants fed formulas low in vitamin B6, in women taking oral contraceptives, and in alcoholics. 

Because the potential benefits outweigh the possibilities of harm, many experts recommend a daily multivitamin that does not exceed the RDA of it component vitamins. Multivitamins ensure an adequate intake for those vitamins—folic acid, vitamin B6, vitamin B12, and vitamin D—that are most likely to be deficient. However, the the evidence is insufficient to recommend for or against the use of supplements of vitamins A, C, or E multivitamins with folic acid or antioxidant combinations for the pre vention of cancer or cardiovascular disease. Most experts recommend against the use of p-carotene supplements, either alone or in combina Don, for the prevention of cancer or cardiovascular disease. 

Two vitamins, nicotinamide and pyridoxine (vitamin B6), are pyridine derivatives. Nicotinamide participates in two coenzymes, coenzyme I (65 R = H) which is known variously as nicotinamide adenine dinucleotide (NAD) or diphosphopyridine nucleotide (DPN), and coenzyme II (65 R = P03H2) also called triphosphopyridine nucleotide (TPN) or nicotinamide adenine dinucleotide phosphate (NADP). These are involved in many oxidation-reduction processes, the quaternized pyridine system acting as a hydrogen acceptor and hydrogen donor. Deficiency of nicotinamide causes pellagra, a disease associated with an inadequately supplemented maize diet. Nicotinic acid (niacin) and its amide are... 

Kratzer (1946) reported that pyridoxine supplementation in chicks on diets containing a linseed meal was necessary to counteract the vitamin B6 deficiency. Klosterman et al. (1967) identified the antipyridoxine factor linatine. Although linatine is a problem in chicks, flaxseed has not been associated with a vitamin B6 deficiency in humans. In fact, no affect on serum pyridoxine levels in subjects consuming 45 grams of flaxseed per day over 5 weeks was observed (Dieken, 1992). 

Clarke R, Collins R. 1998. Can dietary supplements with folic add or vitamin B6 reduce cardiovascular risk Design of clinical trials to test the homocysteine hypothesis of vascular disease. J Cardiovasc Risk 5 249-55. 

Antibiotics. Long-term administration of antibiotics could lead to vitamin B6 deficiency, If symptoms of peripheral neuropathy develop (numbness and tingling of the extremities), administer vitamin B6. Sulfasalazine can decrease the absorption of folic acid, and trimethoprim can cause folate deficiency, hence the need to administer folic acid if there is evidence of deficiency. Rifampicin can cause disturbances in vitamin D metabolism and lead to osteomalacia. The absorption of tetracyclines can be reduced by calcium, magnesium, iron and zinc, while this antibiotic could also decrease the absorption of these minerals. This effect is probably least with minocycline and is not confirmed with doxycycline. Doses of minerals and antibiotic should be separated by at least 2 hours. The absorption of quinolones is reduced by cationic and anionic supplements. 

The long-term intake of hydralazine could lead to vitamin B6 deficiency, while the therapeutic effects of verapamil could be antagonized by calcium supplements. 

Folic acid is one of the B vitamins. Research has established that consuming about 800 micrograms by way of foods and supplements, along with vitamins B6 and B12, reduces levels of the amino acid homocysteine, another risk factor for heart disease. Now recent... 

Pyridoxine (vitamin Bb, in the form of pyridoxal phosphate) is a cofactor in the formation of dopamine from L-DOPA. It used to be thought that pyridoxine supplements would be helpful to treat Parkinson s disease. The opposite was found vitamin B6 apparently also enhances L-DOPA conversion to dopamine in other areas of the body. This means that less of the administered L-DOPA is available for entry into tlie brain. Therefore, Be treatment presently is contraindicated in Parkinson s disease. 

The reaction catalyzed by delta-6-desaturase enzyme is the slowest reaction in the metabolic pathway of LA and is considered as a rate-limiting step (4, 5). Activity of this enzyme further decreases with age and in people suffering from various diseases, including arthritis, diabetes, hypertension, eczema, psoriasis, and so on. Lifestyle factors like stress, smoking, excessive consumption of alcohol, linoleic acid (6), saturated and trans-fatty acids and nutritional deficiencies of Vitamin B6, zinc (7), and magnesium inhibit this desaturase. As a result of limitations in in vivo production of GLA, supplementation with preformed GLA is becoming important. This has led to interest in development and commercialization of the sources of GLA. 

Supplement individuals with vitamin B6 50 mg daily administer isoniazid at least 2 h apart from any foods... 

Various sugars make the listings, denoted by the suffix -ose. Various amino acids also make the listings, denoted by the suffix -ine, notable examples being L-alanine and L-phenylalanine, commonly associated with nutritional supplements. Arginine, an essential amino add (not manufactured in the body), is said to be an inhibitor. The suffix pyridoxal is fisted as an inhibitor, whereby it may be noted that pyridoxine (or pyridoxin) is called vitamin B6. 

Dietary Supplement Fact Sheet Vitamin B6. NIH Office of Diet ary Supplements. 

Rimm, E.B., Willett, W.C., Hu, F.B., Sampson, L., Colditz, G.A., Manson, J.E., Hennekens, C., and Stampfer, M.J., 1998. Folate and vitamin B6 from diet and supplements in relation to risk of coronary heart disease among women. JAMA, the Journal of the American Medical Association. 279 359-364. 

Balk, E.M., Raman, G., Tatsioni, A., Chung, M., Lau, J., and Rosenberg, I.H., 2007. Vitamin B6, B12, and folic acid supplementation and cognitive function a systematic review of randomized trials. Archives of Internal Medicine. 167 21-30. 

Elmazar, M.M., Thiel, R., and Nau, H., 1992. Effect of supplementation with folinic acid, vitamin B6, and vitamin B12 on valproic acid-induced teratogenesis in mice. Eundamentals of Applied Toxicology. 18 389-394. 

Kotsopoulos, J., Hecht, J.L., Marotti, J.D., Kelemen, L.E., and Tworoger, S.S., 2010. Relationship between dietary and supplemental intake of folate, methionine, vitamin B6 and folate receptor alpha expression in ovarian tumors. International Journal of Cancer. 126 2191-2198. 

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