Choline
158799
219081341
2008-06-13T14:03:52Z
68.16.118.226
/* Choline as a supplement */
{{Chembox new
| ImageFile = Choline-skeletal.png
| ImageSize = 200px
| IUPACName = (2-Hydroxyethyl)trimethylammonium
| OtherNames =
| Section1 = {{Chembox Identifiers
| CASNo = 62-49-7
| PubChem = 305
| SMILES = C[N+](C)(C)CCO
| MeSHName = Choline
}}
| Section2 = {{Chembox Properties
| Formula = C<sub>5</sub>H<sub>14</sub>NO<sup>+</sup>
| MolarMass = 104.17 g/mol
| Appearance =
| Density =
| MeltingPt =
| BoilingPt =
}}
| Section3 = {{Chembox Hazards
| Solubility =
| MainHazards =
| FlashPt =
| Autoignition =
}}
}}
'''Choline''' is an [[organic compound]], classified as a water-soluble [[essential nutrient]]<ref>{{pauling|id=othernuts/choline/|title=Choline|author=Jane Higdon}}</ref><ref>"[http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/cho_0283.shtml Choline], ''PDRHealth''</ref><ref>"[http://www.abc.net.au/rn/talks/8.30/helthrpt/stories/s119524.htm Choline]" (An interview with Steven Zeisel, Editor-in-Chief of the Journal of Nutritional Biochemistry), ''Radio National Health Report with Norman Swan'', Monday 17 April 2000</ref> and usually grouped within the [[Vitamin B]] complex. This natural [[amine]] is found in the lipids that make up cell membranes and in the [[neurotransmitter]] [[acetylcholine]]. Adequate intakes (AI) for this [[micronutrient]] of between 425 to 550 milligrams daily, for adults, have been established by the Food and Nutrition Board of the [[Institute of Medicine]] of the [[United States National Academy of Sciences|National Academy of Sciences]].
==History==
Choline was discovered by Andreas Strecker in [[1864]] and [[chemical synthesis|chemically synthesized]] in [[1866]]. In [[1998]] choline was classified as an [[essential nutrient]] by the [[Food and Nutrition Board]] of the [[Institute of Medicine]] ([[United States|U.S.A.]]).
==Chemistry==
Choline is a [[quaternary ammonium cation|quaternary]] [[saturation (chemistry)|saturated]] [[amine]] with the [[chemical formula]]: ([[methyl|CH<sub>3</sub>]])<sub>3</sub>[[Nitrogen|N]]<sup>+</sup>[[methylene|CH<sub>2</sub>]][[methylene|CH<sub>2</sub>]][[hydroxyl|OH]]X<sup>−</sup>.
where X<sup>−</sup> is a [[counterion]] such as [[chloride]] (see [[choline chloride]]), [[hydroxyl|hydroxide]] or [[Tartaric acid|tartrate]].
[[Choline chloride]], in mixture with [[urea]] is used as a solvent ( [[deep eutectic solvent|DES]] ) and the [[salicylate]] salt is used topically for pain relief of [[aphthous ulcer]]s.
==Physiology==
[[Image:Choline_metabolism.png|thumb|300px|right|Choline metabolism. (Choline is green box at left, second from the bottom.)]]
Choline and its [[metabolites]] are needed for three main [[physiology|physiological]] purposes: structural integrity and [[cell signaling|signaling]] roles for cell membranes, cholinergic [[neurotransmission]] ([[acetylcholine]] [[protein biosynthesis|synthesis]]), and as a major source for [[methyl group]]s via its metabolite, [[trimethylglycine]] (betaine) that participates in the [[S-adenosylmethionine]] synthesis [[metabolic pathway|pathways]].
When choline is [[metabolism|metabolized]] by the [[body]], it may form [[trimethylamine]], a compound with a fishy odor. Hence, when large amounts of choline are taken the person may suffer from a fishy [[body odor]].
==Choline as a supplement==
It is well established that supplements of methyl group transfer vitamins [[vitamin B6|B6]], [[vitamin B12|B12]], [[folic acid]] reduce the [[blood]] [[titer]] of [[homocysteine]] and prevent [[cardiovascular disease|heart disease]]. Choline is a necessary source of methyl groups for methyl group transfer. Supplements of [[lecithin]]/choline by Central Soya scientists reduced heart disease in [[clinical trial|laboratory studies]]. The reduction in heart disease with lecithin supplements may however relate more to the [[cholesterol]] carrying capacity of lecithin than to the methyl group transfer role of choline.{{Specify|date=December 2006}}
Choline supplements are often taken as a form of 'smart drug' or [[nootropic]], due to the role that the neurotransmitter [[acetylcholine]] plays in various [[cognition]] systems within the brain. Choline is a chemical precursor or "building block" needed to produce the neurotransmitter acetylcholine, and research suggests that memory, intelligence and mood are mediated at least in part by acetylcholine metabolism in the brain. The compound's [[quaternary amine]] renders it lipid insoluble which might suggest it would be unable to cross the [[blood-brain barrier]]. However, despite choline's lipid insolubility, a choline transporter exists that allows transport across the blood-brain barrier. The efficacy of these supplements in enhancing cognitive abilities is a topic of continuing debate.
Lakhan & Vieira (2008)<ref>Lakhan SE; Vieira KF. [http://www.nutritionj.com/content/7/1/2 Nutritional therapies for mental disorders]. ''Nutrition Journal'' 2008;7(2).</ref> link choline deficiency to bipolar disorder and report efficacy in lecithin supplementation based on a double-blind, placebo controlled trial.
Some people who practice [[lucid dreaming]] use [[Galantamine]] with choline bitartrate or Alpha GPC to increase their odds of having a lucid dream. Acetylcholine precursors such as choline work synergistically with Galantamine to help improve memory and the symptoms of Alzheimer's Disease (AD).
The [[Food and Drug Administration]] (FDA) requires that [[infant formula]] be made from cow's [[milk]] containing choline.<ref>Isadora B. Stehlin, "[http://www.fda.gov/fdac/features/596_baby.html Infant Formula: Second Best but Good Enough]", ''U.S. Food and Drug Administration''.</ref>
Due to its role in [[lipid metabolism]], choline has also found its way into nutritional supplements which claim to reduce [[adipose tissue|body fat]]; but there is little or no [[scientific evidence|evidence]] to prove that it has any effect on reducing excess body fat or that taking high amounts of choline will increase the rate at which fat is metabolised.
==Fish odor syndrome==
{{main|trimethylaminuria}}
Choline is a precursor to [[trimethylamine]], which some persons are not able to break down due to a genetic disorder. Persons suffering from this disorder, called [[trimethylaminuria]], may suffer from a strong fishy or otherwise unpleasant body odor due to the body's release of odorous trimethylamine. A body odor will occur even on a normal diet - ''i.e.'', one that is not particularly high in choline. Persons with trimethylaminuria are advised to restrict the intake of foods high in choline; this may help to reduce the sufferer's body odor.
==Choline hydroxide ==
[[Choline hydroxide]] is one of the class of [[phase transfer catalyst]]s which are used to carry the [[hydroxide]] ion into organic systems. It is far and away the least costly phase transfer catalyst, and gets a lot of use in stripping photoresists in printed circuit board production. Choline hydroxide is not completely stable and it spontaneously, slowly breaks down to release [[trimethylamine]]. It is a strong base.
==Sources==
The foods richest in [[phosphatidylcholine]] — the major delivery form of choline — are [[egg yolks]], [[soybean|soy]] and cooked [[beef]], [[chicken]], [[veal]] and [[turkey]] livers. Many foods contain trace amounts of free choline, even iceberg [[lettuce]]. To what extent these trace forms are usable by [[absorption (digestive)|human digestion]] is still debated. In [[2004]], the [[United States Department of Agriculture|USDA]] released its first database of the choline content in common foods.<ref>"[http://www.nal.usda.gov/fnic/foodcomp/Data/Choline/Choline.html USDA Database for the Choline Content of Common Foods - 2004]", ''USDA Nutrient Data Laboratory''</ref>
The most often available choline [[dietary supplement]] is [[lecithin]], derived from soy or egg yolks, often used as a [[food additive]]. [[Phosphatidylcholine]] is also available as a supplement, in pill or powder form. Supplementary choline is also available as choline chloride, which comes as a liquid due to its hydrophilic properties. Choline chloride is sometimes preferred as a supplement because [[phosphatidylcholine]] can have gastrointestinal side effects.
==Additional images==
<gallery>
Image:Choline_Molecule.png|Choline (C5H14NO+)
Image:Choline chloride.png|[[Choline chloride]]
Image:Choline hydroxide.png|Choline hydroxide
Image:Cholina.png|Synthesis
</gallery>
==References==
<references/>
{{Vitamin}}
[[Category:Alcohols]]
[[Category:Quaternary ammonium compounds]]
[[Category:Dietary supplements]]
[[Category:Nutrition]]
[[Category:Vitamins]]
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