Choline

From New World Encyclopedia
Revision as of 13:13, 17 July 2008 by Rick Swarts (talk | contribs)
Choline
Choline-skeletal.png
IUPAC name (2-Hydroxyethyl)trimethylammonium
Identifiers
CAS number [62-49-7]
PubChem 305
MeSH Choline
SMILES C[N+](C)(C)CCO
Properties
Molecular formula C5H14NO+
Molar mass 104.17 g/mol
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Choline is an organic compound, classified as a water-soluble essential nutrient[1][2][3] 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 National Academy of Sciences.

  • choline is a chemical *** that is considered an essential nutrient for humans (

although historically classified as a member of the vitamin B gropu. choline is not technical a vitamin. A vitamin is. however,...

However, it cannot be manufactured by the human body in ... RDA is Some animals, however, ***


Vitamins are organic (carbon-containing) nutrients obtained through the diet and essential in small amounts for normal metabolic reactions.
B vitamins or vitamin B complex are a group of eight, chemically distinct, water-soluble vitamins that were once considered a single vitamin (like Vitamin C), but now are seen as a complex of vitamins that have loosely similar properties and generally are found in the same foods. Vitamins are organic (carbon-containing) nutrients obtained through the diet and essential in small amounts for normal metabolic reactions in humans.
Many of the following substances have been referred to as vitamins because they were believed to be vitamins at one time. They are relevant to vitamin nomenclature in that the numbers that were assigned to them form "gaps" in the series of B-vitamin names (along with duplicate factors). While they are non-"essential" to humans in that they may be synthesized by the body from other starting materials, they have nutritional significance. Some of them, though not essential to humans, are essential to other organisms.

History

Choline was discovered by Andreas Strecker in 1864 and chemically synthesized in 1866. In 1998 choline was classified as an essential nutrient by the Food and Nutrition Board of the Institute of Medicine (U.S.A.).

Chemistry

Choline is a quaternary saturated amine with the chemical formula: (CH3)3N+CH2CH2OHX. where X is a counterion such as chloride (see choline chloride), hydroxide or tartrate. Choline chloride, in mixture with urea is used as a solvent ( DES ) and the salicylate salt is used topically for pain relief of aphthous ulcers.

Physiology

Choline metabolism. (Choline is green box at left, second from the bottom.)

Choline and its metabolites are needed for three main physiological purposes: structural integrity and signaling roles for cell membranes, cholinergic neurotransmission (acetylcholine synthesis), and as a major source for methyl groups via its metabolite, trimethylglycine (betaine) that participates in the S-adenosylmethionine synthesis pathways.

When choline is 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 B6, B12, folic acid reduce the blood titer of homocysteine and prevent 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 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.

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)[4] 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.[5]

Due to its role in lipid metabolism, choline has also found its way into nutritional supplements which claim to reduce body fat; but there is little or no 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

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 catalysts 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, 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 human digestion is still debated. In 2004, the USDA released its first database of the choline content in common foods.[6]

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

References
ISBN links support NWE through referral fees

  1. Jane Higdon, "Choline", Micronutrient Information Center, Linus Pauling Institute
  2. "Choline, PDRHealth
  3. "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
  4. Lakhan SE; Vieira KF. Nutritional therapies for mental disorders. Nutrition Journal 2008;7(2).
  5. Isadora B. Stehlin, "Infant Formula: Second Best but Good Enough", U.S. Food and Drug Administration.
  6. "USDA Database for the Choline Content of Common Foods - 2004", USDA Nutrient Data Laboratory
  • Bender, D. A., and A. E. Bender. 2005. A Dictionary of Food and Nutrition. New York: Oxford University Press. ISBN 0198609612.


  • Physicians Desk Reference (PDR). 2008. Choline. PDRHealth. Retrieved July 17, 2008.



Vitamins
All B vitamins | All D vitamins
Retinol (A) | Thiamine (B1) | Riboflavin (B2) | Niacin (B3) | Pantothenic acid (B5) | Pyridoxine (B6) | Biotin (B7) | Folic acid (B9) | Cyanocobalamin (B12) | Ascorbic acid (C) | Ergocalciferol (D2) | Cholecalciferol (D3) | Tocopherol (E) | Naphthoquinone (K)

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

The history of this article since it was imported to New World Encyclopedia:

Note: Some restrictions may apply to use of individual images which are separately licensed.