B vitamins
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List of B vitamins
[[Image:B vitamin supplement tablets.jpg|thumb|B [[vitamin supplement]] tablets]]
The '''B vitamins''' are eight water-soluble [[vitamin]]s that play important roles in [[Cell (biology)|cell]] [[metabolism]]. Historically, the B vitamins were once thought to be a single vitamin, referred to as '''vitamin B''' (much like how people refer to [[vitamin C]] or [[vitamin D]]). Later research showed that they are [[chemical]]ly distinct vitamins that often coexist in the same foods. Supplements containing all eight are generally referred to as a '''vitamin B complex'''. Individual B vitamin supplements are referred to by the specific name of each vitamin (e.g. B<sub>1</sub>, B<sub>2</sub>, B<sub>3</sub>).
==List of B vitamins==
* '''[[Vitamin B1|Vitamin B<sub>1</sub>]]''' ([[thiamine]])
* '''Vitamin B<sub>2</sub>''' ([[riboflavin]])
* '''Vitamin B<sub>3</sub>''' ([[niacin]], includes [[nicotinic acid]] and [[nicotinamide]]), vitamin PP
* '''Vitamin B<sub>5</sub>''' ([[pantothenic acid]])
* '''[[Vitamin B6|Vitamin B<sub>6</sub>]]''' ([[pyridoxine]])
* '''Vitamin B<sub>7</sub>''' ([[biotin]]), vitamin H
* '''Vitamin B<sub>9</sub>''' ([[folic acid]]), vitamin M, vitamin B-c
* '''[[Vitamin B12|Vitamin B<sub>12</sub>]]''' (cyano [[cobalamin]])
''note'':
* '''''Vitamin B<sub>4</sub>''' ([[adenine]], DNA metabolite) is no longer classified as a vitamin because it is synthesized by the human body''
* '''''Vitamin B<sub>8</sub>''' ([[inositol|myo-inositol]], adenylic acid, DNA metabolite) is no longer classified as a vitamin because it is synthesized by the human body''
* '''''Vitamin B<sub>15</sub>''' ([[pangamic acid]]) is not widely accepted as a vitamin because it has not been shown to be essential in the human diet
* '''''Vitamin B<sub>17</sub>''' ([[amygdalin]], laetrille) is not yet classified
==B vitamin deficiency==
Several named vitamin deficiency diseases may result from the lack of sufficient B-vitamins. Deficiencies of other B vitamins result in symptoms that are not part of a named deficiency disease.
{| class="wikitable"
| '''Vitamin''' || '''Name''' || '''Deficiency effects'''
|-
| '''Vitamin B<sub>1</sub>''' || [[thiamine]] || Deficiency causes [[beriberi]]. Symptoms of this disease of the [[nervous system]] include weight loss, emotional disturbances, [[Wernicke's encephalopathy]] (impaired sensory perception), weakness and pain in the limbs, periods of [[arrhythmia|irregular heartbeat]], and [[edema]] (swelling of bodily tissues). [[Heart failure]] and [[death]] may occur in advanced cases. Chronic thiamine deficiency can also cause [[Korsakoff's syndrome]], an irreversible psychosis characterized by [[amnesia]] and [[confabulation]].
|-
| '''Vitamin B<sub>2</sub>''' || [[riboflavin]] || Deficiency causes [[ariboflavinosis]]. Symptoms may include cheilosis (cracks in the lips), high sensitivity to sunlight, [[angular cheilitis]], [[glossitis]] (inflammation of the tongue), [[seborrheic dermatitis]] or pseudo-[[syphilis]] (particularly affecting the [[scrotum]] or [[labia majora]] and the [[nasolabial folds|mouth]]), [[sore throat|pharyngitis]], [[hyperemia]], and edema of the [[pharyngeal]] and [[Wiktionary:oral|oral]] [[mucus membranes|mucosa]].
|-
| '''Vitamin B<sub>3</sub>''' || [[niacin]] || Deficiency, along with a deficiency of [[tryptophan]] causes [[pellagra]]. Symptoms include aggression, [[dermatitis]], [[insomnia]], [[weakness]], mental confusion, and [[diarrhea]]. In advanced cases, pellagra may lead to [[dementia]] and death.
|-
| '''Vitamin B<sub>5</sub>''' || [[pantothenic acid]] || Deficiency can result in [[acne]] and [[paresthesia]], although it is uncommon.
|-
| '''Vitamin B<sub>6</sub>''' || [[pyridoxine]] || Deficiency may lead to [[anemia]], [[clinical depression|depression]], dermatitis, high blood pressure ([[hypertension]]), water retention, and elevated levels of [[homocysteine]].
|-
| '''Vitamin B<sub>7</sub>''' || [[biotin]] || Deficiency does not typically cause symptoms in adults but may lead to impaired growth and neurological disorders in infants.
|-
| '''Vitamin B<sub>9</sub>''' || [[folic acid]] || Deficiency results in a [[Megaloblastic anemia|macrocytic anemia]], and elevated levels of [[homocysteine]]. Deficiency in pregnant women can lead to birth defects. Supplementation is often recommended during pregnancy. Researchers have shown that folic acid might also slow the insidious effects of age on the brain.
|-
| '''Vitamin B<sub>12</sub>''' || [[cobalamin]] || Deficiency causes [[megaloblastic anemia|macrocytic anemia]], elevated [[homocysteine]], [[peripheral neuropathy]], memory loss and other cognitive deficits. It is most likely to occur among elderly people as absorption through the gut declines with age; the autoimmune disease [[pernicious anemia]] is another common cause. In rare extreme cases, paralysis can result.
|}
==Related nutrients==
Many of the following substances have been referred to as vitamins because they were believed to be vitamins at one time, and they are relevant to vitamin nomenclature in that the numbers that were assigned to them form "gaps" in the series of B-vitamin names. Some of them, though not essential to humans, are essential in the diets of other organisms; others have no known nutritional value. See also [[Orthomolecular medicine]].
*'''Vitamin B<sub>4</sub>''': [[Adenine]], a [[nucleobase]].<ref>Vera Reader (1930). "The assay of vitamin B4". Biochem J. 24 (6): 1827–31.</ref>
*'''Vitamin B<sub>7</sub>''': "Vitamin I" of Centanni E. (1935) — also called 'Enteral factor' — is a water and alcohol soluble rice-bran factor which prevents digestive disturbance in pigeons. It governs the anatomical and functional integrity of the intestinal tract. Later found in yeast. Possible candidates for this substance are [[inositol]], [[niacin]] (nicotinic acid), and [[biotin]]. Carnitine was also claimed to be a candidate but is not soluble in alcohol.{{Fact|date=February 2007}}
*'''Vitamin B<sub>8</sub>''': [[adenosine monophosphate]], or alternately [[inositol]] has also been called vitamin B<sub>8</sub>
*'''Vitamin B<sub>10</sub>''': [[4-Aminobenzoic acid|para-aminobenzoic acid, or PABA]]
*'''Vitamin B<sub>11</sub>''': [[Pteryl-hepta-glutamic acid]] – Chick growth factor, which is a form of Folic acid. Later found to be one of five [[folate]]s necessary for humans; also known as Vitamin S or Factor S. ([[Carnitine|L-carnitine]]) is called Vitamin B<sub>11</sub> in France{{Fact|date=February 2007}}.
*'''Vitamin B<sub>13</sub>''': [[Pyrimidinecarboxylic acid|Orotic acid]].
*'''Vitamin B<sub>14</sub>''': cell proliferant, anti-anemia, rat growth, and antitumor pterin phosphate named by Earl R. Norris (biochemist of folic acid fame). Isolated from human urine at 0.33ppm (later in blood), but later abandoned by him as further evidence did not confirm this. He also claimed this was not Xanthopterin. <!--This needs a rewrite-->
*'''Vitamin B<sub>15</sub>''' 6-O-(dimethylaminoacetyl)-D-gluconic acid ([[Pangamic acid]])
*'''Vitamin B<sub>16</sub>''' ([[dimethylglycine]]) – also known as DMG. (However Lipoic acid was discovered and named a B-Vitamin after B15 and before B17)
*'''Vitamin B<sub>17</sub>''' ([[Amygdalin]], Nitrilosides, or [[laetrile]]) – A substance found in a number of seeds, sprouts, beans, tubers and grains. While toxic in large quantities, proponents claim that it is effective in cancer treatment and prevention. <ref>{{cite news|first=Jim|last=Clark|title=Foods Containing B17|Publisher=All Natural Cancer Therapy|date=September 2003|accessdate=2007-07-07|url=http://web.archive.org/web/20070828221422/http://home.bluegrass.net/~jclark/b17_dosage.htm}}</ref>
*'''Vitamin B<sub>18</sub>''' –
*'''Vitamin B<sub>19</sub>''' –
*'''Vitamin B<sub>20</sub>''' ([[Carnitine]]) –
*'''Vitamin B<sub>21</sub>''' –
*'''Vitamin B<sub>22</sub>''' – often claimed as an ingredient of [[Aloe|Aloe vera]] extracts but also in many other foods. Claimed by one source to be Vitamin B12b-δ.
*'''Vitamin B<sub>h</sub>''' – another name for [[Biotin]]
*'''Vitamin B<sub>m</sub>''''' ("mouse factor") – also used to designate Inositol
*'''Vitamin B<sub>p</sub>''' ([[Choline]]) – {{Dubious|date=March 2008}}
*'''Vitamin B<sub>t</sub>''' ([[Carnitine|L-carnitine]]) –
*'''Vitamin B<sub>v</sub>''' – a type of B<sub>6</sub> but not Pyridoxine
*'''Vitamin B<sub>w</sub>''' – a type of Biotin but not d-Biotin
*'''Vitamin B<sub>x</sub>''' – another name for PABA ([[para-Aminobenzoic acid|''para''-Aminobenzoic acid]])
* '''Lipoic acid''' –
Note: '''B<sub>16</sub>''', '''B<sub>17</sub>''', '''B<sub>18</sub>''', '''B<sub>19</sub>''', '''B<sub>20</sub>''', '''B<sub>21</sub>''' & '''B<sub>22</sub>''' do not appear to be animal factors but are claimed by some naturopaths as human therapedic factors.
==Health benefits==
The B vitamins often work together to deliver a number of health benefits to the body. B vitamins have been shown to:
* Support and increase the rate of [[metabolism]]
* Maintain healthy skin and muscle tone
* Enhance [[immune system|immune]] and [[nervous system]] function
* Promote [[cell growth]] and [[cell division|division]] — including that of the [[red blood cell]]s that help prevent [[anemia]].
* Reduce the risk of [[pancreatic cancer]], one of the most lethal forms of cancer<ref>{{cite web|url= http://www.pancreatica.org |title=Confronting Pancreatic Cancer |accessdate=2008-02-08}}</ref>, when consumed in food, but not when ingested in vitamin tablet form.<ref>{{cite web |url=http://cancerres.aacrjournals.org/cgi/content/abstract/67/11/5553 |title=Plasma Folate, Vitamin B6, Vitamin B12, and Homocysteine and Pancreatic Cancer Risk in Four Large Cohorts -- Schernhammer et al. 67 (11): 5553 -- Cancer Research |accessdate=2008-02-08 |format= |work=}}</ref><ref>{{cite web |url=http://www.upi.com/Consumer_Health_Daily/Briefing/2007/06/01/pancreatic_cancer_risk_cut_by_b6_b12/3712/ |title=United Press International - Consumer Health Daily - Briefing |accessdate=2008-02-08 |format= |work=}}</ref>
Together, they also help combat the symptoms and causes of [[stress (medicine)|stress]], [[clinical depression|depression]], and [[cardiovascular disease]].
All B vitamins are water soluble, and are dispersed throughout the body. Most of the B vitamins must be replenished daily, since any excess is excreted in the [[urine]].<ref>Vitamins, water soluble at FAQ.org[http://www.faqs.org/nutrition/Smi-Z/Vitamins-Water-Soluble.html]</ref> A six year cobalamin store can be found in the liver, despite its water soluble nature. {{Fact|date=June 2008}}
==Vitamin B sources==
Different B vitamins come from different natural sources, such as [[potato]]es, [[banana]]s, [[lentil]]s, [[chilli pepper]]s, [[tempeh]], [[liver oil]], [[liver]], [[Turkey (bird)|turkey]], [[tuna]], [[Nutritional yeast]] (or [[brewer's yeast]]) and [[molasses]]. [[Marmite]] and [[Vegemite]] bill themselves as "one of the world's richest known sources of vitamin B". As might be expected, due to its high content of brewer's yeast, [[beer]] is a source of B vitamins<ref>{{cite news|first=Gregg|last=Glaser|title=Beer and Your Health|Publisher=All About Beer Magazine|date=July 2002|accessdate=2007-01-05|url=http://www.allaboutbeer.com/features/233beer&health.html}}</ref>, although this may be less true for filtered beers<ref>{{cite paper| author =Harden, A and Zylva, S S| title =Investigation of Barley, Malt and Beer for Vitamins B and C| publisher =Lister Institute| date =[[1924-07-21]]| url =http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1259493&blobtype=pdf| format =[[PDF]]| accessdate = 2007-01-05 }}</ref>and the alcohol in beer impairs the body's ability to activate vitamins.
The B-12 vitamin is of note because it is not available from plant products, making B-12 deficiency a concern for [[vegan]]s. Manufacturers of plant-based foods will sometimes report B-12 content, leading to confusion about what sources yield B-12. The confusion arises because the standard US Pharmacopeia (USP) method for measuring the B-12 content does not measure the B-12 directly. Instead, it measures a bacterial response to the food. Chemical variants of the B-12 vitamin found in plant sources are active for bacteria, but cannot be used by the human body. This same phenomenon can cause significant over-reporting of B-12 content in other types of foods as well.<ref> {{cite journal|title=Vitamin B-12: Plant sources, requirements, and assay|journal=Am. J. Clin. Nutr.|date=1998|first=Victor|last=Herbert|coauthors=|volume=48|issue=|pages=852–8|id= |url=http://www.ajcn.org/cgi/reprint/48/3/852|format=|accessdate=2008-02-26 }}</ref>
Another popular means of increasing one's vitamin B intake is through the use of [[dietary supplement]]s purchased at supermarkets, health centers, or natural food stores. B vitamins are also commonly added to [[energy drinks]].
==Mnemonic==
One mnemonic to remember the most commonly referenced B vitamins is "The (B1, Thiamine) Rhythm (B2, Riboflavin) Nearly (B3, Niacin) Proved (B6, Pyridoxine) Contagious (B12, Cobalamin)".<ref>{{MedicalMnemonics|399|||}}</ref>
==References==
{{Reflist|2}}
==External links==
* [http://home.howstuffworks.com/vitamin-b.htm How B Vitamins Work] at [[HowStuffWorks]]
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