Information about Vitamin B6
Vitamin B6 is a water-soluble vitamin. Pyridoxal phosphate (PLP) is the active form and is a cofactor in many reactions of amino acid metabolism, including transamination, deamination, and decarboxylation. PLP also is necessary for the enzymatic reaction governing the release of glucose from glycogen.
Enzymes dependent on PLP focus a wide variety of chemical reactions mainly involving amino acids. The reactions carried out by the PLP-dependent enzymes that act on amino acids include transfer of the amino group, decarboxylation, racemization, and beta- or gamma-elimination or replacement. Such versatility arises from the ability of PLP to covalently bind the substrate, and then to act as an electrophilic catalyst, thereby stabilizing different types of carbanionic reaction intermediates.
Overall, the Enzyme Commission (EC; [1] has catalogued more than 140 PLP-dependent activities, corresponding to ~4% of all classified activities.
In the early 1990s, it was suggested in megadoses as treatment for PMS and clinical depression, but this is no longer considered effective. [1]
Vitamin B6 is prevalent in both animal and vegetable food sources. Avocados, nuts, liver, chicken, fish, green beans, field salad, wheat germ, nutritional yeast, sea vegetables, and bananas are particularly good food sources.
Vitamin B6 is a co-factor for glutamic acid decarboxylase, an enzyme that converts Glutamate to GABA. Therefore, the concurrent increase in the excitatory neurotransmitter, Glutamate, and decrease in inhibitory neurotransmitter, GABA, resultant from B6 deficiency, may manifest itself in the form of seizures.
Because adverse effects have only been documented from vitamin B6 supplements and never from food sources, this article only discusses the safety of the supplemental form of vitamin B6 (pyridoxine). Although vitamin B6 is a water-soluble vitamin and is excreted in the urine, very high doses of pyridoxine over long periods of time may result in painful neurological symptoms known as sensory neuropathy. Symptoms include pain and numbness of the extremities, and in severe cases difficulty walking. Sensory neuropathy typically develops at doses of pyridoxine in excess of 1,000 mg per day. However, there have been a few case reports of individuals who developed sensory neuropathies at doses of less than 500 mg daily over a period of months. None of the studies, in which an objective neurological examination was performed, found evidence of sensory nerve damage at intakes of pyridoxine below 200 mg/day. In order to prevent sensory neuropathy in virtually all individuals, the Food and Nutrition Board of the Institute of Medicine set the tolerable upper intake level (UL) for pyridoxine at 100 mg/day for adults. Because placebo-controlled studies have generally failed to show therapeutic benefits of high doses of pyridoxine, there is little reason to exceed the UL of 100 mg/day. Studies have shown, however, that in the case of individuals diagnosed with autism, high doses of vitamin B6 given with magnesium have been found to be extremely beneficial.
The intake of vitamin B6, from either diet or supplements, could cut the risk of Parkinson’s disease by half according to a prospective study from the Netherlands. "Stratified analyses showed that this association was restricted to smokers," wrote the authors.[6]
Nutritional supplementation with high dose vitamin B6 and magnesium is claimed to alleviate the symptoms of autism and is one of the most popular complementary and alternative medicine choices for autism. Three small randomized controlled trials have studied this therapy; the smallest one (with 8 individuals) found improved verbal IQ in the treatment group and the other two (with 10 and 15 individuals, respectively) found no significant difference. The short-term side effects seem to be mild, but there may be significant long-term side effects of peripheral neuropathy.[7] Some studies suggest that the B6-magnesium combination can also help attention deficit disorder , citing improvements in hyperactivity, hyperemotivity/aggressiveness and improved school attention. [8]
It is also suggested that ingestion of vitamin B6 can alleviate some of the many symptoms of an alcoholic hangover and morning sickness from pregnancy. This might be due to B6's mild diuretic effect[9].
The double blind method is an important part of the scientific method, used to prevent research outcomes from being 'influenced' by either the placebo effect or the observer bias.
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)
)
Forms
Seven forms of this vitamin are known:- pyridoxine (PN). PN is the form that is given as vitamin B6 supplement.
- pyridoxine 5'-phosphate (PNP).
- pyridoxal (PL).
- pyridoxal 5'-phosphate (PLP). PLP is the metabolically active form.
- pyridoxamine (PM).
- pyridoxamine 5'-phosphate (PMP).
- 4-pyridoxic acid (PA). PA is the catabolite which is excreted in the urine.
History
Vitamin B6 is a water-soluble compound that was discovered in the 1930s during nutrition studies on rats. The vitamin was named pyridoxine to indicate its structural homology to pyridine. Later it was shown that vitamin B6 could exist in two other, slightly different, chemical forms, termed pyridoxal and pyridoxamine. All three forms of vitamin B6 are precursors of an activated compound known as pyridoxal 5'-phosphate (PLP), which plays a vital role as the cofactor of a large number of essential enzymes in the human body.Enzymes dependent on PLP focus a wide variety of chemical reactions mainly involving amino acids. The reactions carried out by the PLP-dependent enzymes that act on amino acids include transfer of the amino group, decarboxylation, racemization, and beta- or gamma-elimination or replacement. Such versatility arises from the ability of PLP to covalently bind the substrate, and then to act as an electrophilic catalyst, thereby stabilizing different types of carbanionic reaction intermediates.
Overall, the Enzyme Commission (EC; [1] has catalogued more than 140 PLP-dependent activities, corresponding to ~4% of all classified activities.
In the early 1990s, it was suggested in megadoses as treatment for PMS and clinical depression, but this is no longer considered effective. [1]
Sources
The United States RDA varies between 1.3 mg and 2.0 mg, depending upon age and gender.Vitamin B6 is prevalent in both animal and vegetable food sources. Avocados, nuts, liver, chicken, fish, green beans, field salad, wheat germ, nutritional yeast, sea vegetables, and bananas are particularly good food sources.
Deficiencies
- Supporters of a debated medical condition known as Pyroluria believe it may be one potential cause of vitamin B6 deficiency.
- Another cause of vitamin B6 deficiency is the use of the tuberculostatic medication isoniazid, and for this reason, it is recommended to supplement with vitamin B6 when using this drug.
- Grumpiness and irritability are also often symptomatic of a deficiency according to "Body, Mind, and the B Vitamins" by Ruth Adams and Frank Murray.
- A meta-analysis of three databases (MEDLINE, EMBASE, and Cochrane Library), including only double-blind, randomized controlled trials, found that vitamin B6 has a significant effect compared to placebos in treating morning sickness, similar to that of ginger.[2]
Vitamin B6 is a co-factor for glutamic acid decarboxylase, an enzyme that converts Glutamate to GABA. Therefore, the concurrent increase in the excitatory neurotransmitter, Glutamate, and decrease in inhibitory neurotransmitter, GABA, resultant from B6 deficiency, may manifest itself in the form of seizures.
Diagnostic Testing for B6 Deficiency
A positive diagnosis test for pyridoxine deficiency can be assertained by measuring erythrocyte levels of aspartate aminotransferase and transketolase in serum.Overdose
An overdose of pyridoxine can cause a temporary deadening of certain nerves such as the proprioceptory nerves; causing a feeling of disembodiment common with the loss of proprioception. This condition is reversible when supplementation is stopped.[4]Because adverse effects have only been documented from vitamin B6 supplements and never from food sources, this article only discusses the safety of the supplemental form of vitamin B6 (pyridoxine). Although vitamin B6 is a water-soluble vitamin and is excreted in the urine, very high doses of pyridoxine over long periods of time may result in painful neurological symptoms known as sensory neuropathy. Symptoms include pain and numbness of the extremities, and in severe cases difficulty walking. Sensory neuropathy typically develops at doses of pyridoxine in excess of 1,000 mg per day. However, there have been a few case reports of individuals who developed sensory neuropathies at doses of less than 500 mg daily over a period of months. None of the studies, in which an objective neurological examination was performed, found evidence of sensory nerve damage at intakes of pyridoxine below 200 mg/day. In order to prevent sensory neuropathy in virtually all individuals, the Food and Nutrition Board of the Institute of Medicine set the tolerable upper intake level (UL) for pyridoxine at 100 mg/day for adults. Because placebo-controlled studies have generally failed to show therapeutic benefits of high doses of pyridoxine, there is little reason to exceed the UL of 100 mg/day. Studies have shown, however, that in the case of individuals diagnosed with autism, high doses of vitamin B6 given with magnesium have been found to be extremely beneficial.
Preventive roles and therapeutic uses
At least one preliminary study has found that this vitamin may increase dream vividness or the ability to recall dreams.[5] It is thought that this effect may be due to the role this vitamin plays in the conversion of tryptophan to serotonin.<ref name="ebben" />The intake of vitamin B6, from either diet or supplements, could cut the risk of Parkinson’s disease by half according to a prospective study from the Netherlands. "Stratified analyses showed that this association was restricted to smokers," wrote the authors.[6]
Nutritional supplementation with high dose vitamin B6 and magnesium is claimed to alleviate the symptoms of autism and is one of the most popular complementary and alternative medicine choices for autism. Three small randomized controlled trials have studied this therapy; the smallest one (with 8 individuals) found improved verbal IQ in the treatment group and the other two (with 10 and 15 individuals, respectively) found no significant difference. The short-term side effects seem to be mild, but there may be significant long-term side effects of peripheral neuropathy.[7] Some studies suggest that the B6-magnesium combination can also help attention deficit disorder , citing improvements in hyperactivity, hyperemotivity/aggressiveness and improved school attention. [8]
It is also suggested that ingestion of vitamin B6 can alleviate some of the many symptoms of an alcoholic hangover and morning sickness from pregnancy. This might be due to B6's mild diuretic effect[9].
External links
- Facts about Vitamin B6 from Office of Dietary Supplements at National Institutes of Health
- The B6 database A database of B6-dependent enzymes at University of Parma
- Vitamin B6 Information Sheet from the Linus Pauling Institute at Oregon State University
- Vitamin B6 (and magnesium) in the treatment of autism from the Autism Research Institute
- MeSH Vitamin+B6
References
1. ^ [2]
2. ^ Pregnancy Morning Sickness - Ginger as Effective as Vitamin B6 (open) Effectiveness and Safety of Ginger in the Treatment of Pregnancy-Induced Nausea and Vomiting (subscription), Borrelli et al., Obstetrics & Gynecology, 2005;105:849-856
3. ^ Andrews' Diseases of the Skin, 10th Edition, Elsevier.
4. ^ Vitamin and Mineral Supplement Fact Sheets Vitamin B6
5. ^ Ebben, M., Lequerica, A., & Spielman A. (2002). Effects of pyridoxine on dreaming: a preliminary study. Perceptual & Motor Skills, 94(1), 135–140.
6. ^ Increased intake of vitamin B6Sheet. Retrieved on 2006-08-11.
7. ^ Angley M, Semple S, Hewton C, Paterson F, McKinnon R (2007). "Children and autism—part 2—management with complementary medicines and dietary interventions" (PDF). Aust Fam Physician 36 (10): 827–30. PMID 17925903.
8. ^ "Improvement of neurobehavioral disorders in children supplemented with magnesium-vitamin B6. I. Attention deficit hyperactivity disorders." Magnes Res. 2006 Mar;19(1):46-52. PMID: 16846100
9. ^ THE MYSTERIOUS VITAMIN B6. By Dr. Russ Ebbets. Off The Road Column
2. ^ Pregnancy Morning Sickness - Ginger as Effective as Vitamin B6 (open) Effectiveness and Safety of Ginger in the Treatment of Pregnancy-Induced Nausea and Vomiting (subscription), Borrelli et al., Obstetrics & Gynecology, 2005;105:849-856
3. ^ Andrews' Diseases of the Skin, 10th Edition, Elsevier.
4. ^ Vitamin and Mineral Supplement Fact Sheets Vitamin B6
5. ^ Ebben, M., Lequerica, A., & Spielman A. (2002). Effects of pyridoxine on dreaming: a preliminary study. Perceptual & Motor Skills, 94(1), 135–140.
6. ^ Increased intake of vitamin B6Sheet. Retrieved on 2006-08-11.
7. ^ Angley M, Semple S, Hewton C, Paterson F, McKinnon R (2007). "Children and autism—part 2—management with complementary medicines and dietary interventions" (PDF). Aust Fam Physician 36 (10): 827–30. PMID 17925903.
8. ^ "Improvement of neurobehavioral disorders in children supplemented with magnesium-vitamin B6. I. Attention deficit hyperactivity disorders." Magnes Res. 2006 Mar;19(1):46-52. PMID: 16846100
9. ^ THE MYSTERIOUS VITAMIN B6. By Dr. Russ Ebbets. Off The Road Column
Vitamins (A11) | |
|---|---|
| fat soluble | Retinol (A) | Ergocalciferol and Cholecalciferol (D) | Tocopherol (E) | Naphthoquinone (K) |
| water soluble | B vitamins (Thiamine (B1), Riboflavin (B2), Niacin (B3), Pantothenic acid (B5), Pyridoxine (B6), Biotin (B7), Folic acid (B9), Cyanocobalamin (B12)) | Choline | Ascorbic acid (C) |
A vitamin is a nutrient that is an organic compound required in tiny amounts for essential metabolic reactions in a living organism.[1] The term vitamin
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EC1 Oxidoreductases/list - EC2 Transferases/list - EC3 Hydrolases/list - EC4 Lyases/list - EC5 Isomerases/list - EC6 Ligases/list
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amino acid is a molecule that contains both amine and carboxyl functional groups. In biochemistry, this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent.
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Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. The living cell uses it as a source of energy and metabolic intermediate.
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Glycogen is a polysaccharide of glucose (Glc) which functions as the primary short term energy storage in animal cells. It is made primarily by the liver and the muscles, but can also be made by the brain, uterus, and the vagina.
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Pyridoxine is one of the compounds that can be called vitamin B6, along with Pyridoxal and Pyridoxamine. It differs from pyridoxamine by the substituent at the '4' position. It is often used as 'pyridoxine hydrochloride'.
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Pyridoxal is one of the three natural forms of vitamin B6, along with pyridoxamine and pyridoxine (also called "pyridoxol"). All of these forms are converted in the human body into a single biologically active form, pyridoxal 5-phosphate.
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Pyridoxal-phosphate (PLP, pyridoxal-5'-phosphate) is a coenzyme of many enzymatic reactions. It is the active form of vitamin B 6 which comprises three natural organic compounds, pyridoxal, pyridoxamine and pyridoxine.
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Pyridoxamine is one of the compounds composing vitamin B6, along with Pyridoxal and Pyridoxine. It is converted to the biologically active form pyridoxal 5-phosphate.
It is based on a pyridine ring, with hydroxyl, methyl, aminomethyl, and hydroxymethyl substituents.
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It is based on a pyridine ring, with hydroxyl, methyl, aminomethyl, and hydroxymethyl substituents.
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Pyridine is a chemical compound with the formula C5H5N. It is a liquid with a distinctively putrid, fishy odour. Pyridine is a simple and fundamentally important heterocyclic aromatic organic compound that is structurally related to benzene, wherein one CH
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PMS is a three-letter initialism which may mean:
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- Premenstrual syndrome, a collection of physical, psychological and emotional symptoms related to a woman's menstrual cycle
- Postmarketing surveillance
- Pantone Matching System, a colour space
- P.M.S.
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Depression
Classification & external resources
ICD-10 F 32. , F 33.
ICD-9 296
OMIM 608516
DiseasesDB 3589
MedlinePlus 003213
eMedicine med/532
Clinical depression (also called major-depressive disorder, or
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Classification & external resources
ICD-10 F 32. , F 33.
ICD-9 296
OMIM 608516
DiseasesDB 3589
MedlinePlus 003213
eMedicine med/532
Clinical depression (also called major-depressive disorder, or
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The Dietary Reference Intake is a system of nutrition recommendations from the Institute of Medicine of the USA National Academy (IOM). The DRI system is used by both the United States and Canada. It is intended for the general public and health professionals.
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P. americana
Binomial name
Persea americana
Mill.
The avocado (Persea americana) is a tree native to Mexico and Central America, classified in the flowering plant family Lauraceae.
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Binomial name
Persea americana
Mill.
The avocado (Persea americana) is a tree native to Mexico and Central America, classified in the flowering plant family Lauraceae.
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chicken (Gallus gallus) is a type of domesticated fowl, believed to be descended from the wild Indian and south-east Asian Red Junglefowl.
The chicken is one of the most common and wide-spread domestic animals.
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The chicken is one of the most common and wide-spread domestic animals.
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Fish as a food describes the edible parts of water-dwelling, cold-blooded vertebrates with gills. Other edible water-dwelling animals such as mollusks, crustaceans, and shellfish may also be classified as fish but are often referred to as shellfish.
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Green beans (American English) or French beans (British English) are the unripe fruits of any kind of bean, including the yardlong bean, the hyacinth bean, the winged bean, and especially the common bean (Phaseolus vulgaris), whose pods are also usually called
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Salad is a light meal — or, more commonly a part of a larger meal, such as an appetizer — consisting of mixed vegetables (usually including at least one leaf vegetable) or fruit, often with a dressing or sauce, occasionally nuts and sometimes with the addition of meat,
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The germ is the "heart" of the cereal kernel, the embryo of the seed, and a concentrated source of several essential nutrients including Vitamin E, folate (folic acid), phosphorus, thiamin, zinc and magnesium, as well as essential fatty acids and fatty alcohols.
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Nutritional yeast, similar to brewer's yeast, is a nutritional supplement popular with vegans and the health conscious, who use it as an ingredient in recipes or simply as a condiment. It is a deactivated yeast, usually Saccharomyces cerevisiae.
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BANANA (an acronym of Build Absolutely Nothing Anywhere Near Anything or possibly Build Absolutely Nothing Anywhere Near Anyone
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This article or section may contain inappropriate or misinterpreted which do not the text.
Please help [ improve this article] by checking for inaccuracies. This article has been tagged since April 2007.
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Please help [ improve this article] by checking for inaccuracies. This article has been tagged since April 2007.
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Isoniazid is also called isonicotinyl hydrazine or INH. Isoniazid is a first-line antituberculous medication used in the prevention and treatment of tuberculosis. Isoniazid is never used on its own to treat active tuberculosis because resistance quickly develops.
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In statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. The first meta-analysis was performed by Karl Pearson in 1904, in an attempt to overcome the problem of reduced statistical power in studies with small sample
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MEDLINE (Medical Literature Analysis and Retrieval System Online) is an international literature database of life sciences and biomedical information. It covers the fields of medicine, nursing, pharmacy, dentistry, veterinary medicine, and health care.
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EMBASE [1] is a biomedical and pharmacological database containing over 11 million records from 1974 to present. Each record is fully indexed and it covers over 5,000 biomedical journals from 70 countries.
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The Cochrane Library is a collection of databases in medicine and other healthcare specialties provided by the Cochrane Collaboration. At its core is a database of systematic reviews and meta-analyses which summarise and interpret the results of high-quality medical research.
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For the communication paradox, see .
The double blind method is an important part of the scientific method, used to prevent research outcomes from being 'influenced' by either the placebo effect or the observer bias.
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Placebo effect is the term applied by medical science to the therapeutical and healing effects of inert medicines and/or ritualistic or faith healing manipulations.[1] [2].
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Morning sickness, also called nausea, vomiting of pregnancy (emesis gravidarum or NVP), or pregnancy sickness, affects between 50 [1]
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