Choline

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Choline

Identifiers
CAS number	[62-49-7]
PubChem	305
MeSH	Choline
Properties
Molecular formula	C5H14NO+
Molar mass	104.171
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

1 History
2 Chemistry
3 Physiology
4 Choline as a supplement
5 Sources
6 Additional images
7 References
8 External links

[edit] History

Choline was discovered by Andreas Strecker in 1862 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.) and Adequate Intakes (AI) have been established.

[edit] Chemistry

Choline is a quaternary saturated amine with the chemical formula

(CH₃)₃N⁺CH₂ CH₂ OHX⁻.

where X⁻ is a counterion such as chloride (see choline chloride), hydroxide or tartrate.

[edit] 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.

[edit] Choline as a supplement

The Food and Drug Administration (FDA) requires that infant formula be made from cow's milk containing choline.^[1]

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.

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.^[specify]

Choline supplements are often taken as a form of 'smart drug' or nootropic, due to the 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 and intelligence are mediated at least in part by acetylcholine metabolism in the brain. The efficacy of these supplements in enhancing cognitive abilities is a topic of continuing debate.

[edit] 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.^[2]