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|Section2= |Section3= |Section4= |Section5= |Section6= |Section7= |Section8= }} Choline is a water-soluble nutrient.〔"(Choline ), ''PDRHealth''〕〔"(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〕〔"()" Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (1998), Institute of Medicine.〕 It is usually grouped within the B-complex vitamins. Choline generally refers to the various quaternary ammonium salts containing the ''N'',''N'',''N''-trimethylethanolammonium cation. (X− on the right denotes an undefined counteranion.) The cation appears in the head groups of phosphatidylcholine and sphingomyelin, two classes of phospholipid that are abundant in cell membranes. Choline is the precursor molecule for the neurotransmitter acetylcholine, which is involved in many functions including memory and muscle control. Some animals must consume choline through their diet to remain healthy. To humans, choline is not an essential nutrient unless the diet is also devoid of methionine and folate.〔 It is used in the synthesis of components in cell membranes. The 2005 National Health and Nutrition Examination Survey stated that only 2% of postmenopausal women consume the recommended intake for choline. ==History== Choline was first isolated by Adolph Strecker from pig and ox bile (Greek: χολή, ''chole'') in 1862. When it was first chemically synthesized by Oscar Liebreich in 1865,〔 it was known as ''neurine'' until 1898 when it was shown to be chemically identical to choline. In 1998, choline was classified as an essential nutrient by the Food and Nutrition Board of the Institute of Medicine (USA).〔(【引用サイトリンク】url=http://www.cholineinfo.org/healthcare_professionals/overview.asp )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Choline」の詳細全文を読む スポンサード リンク
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