叶酸

叶酸
臨床資料
其他名稱	FA, N-(4-{[(2-amino-4-oxo-1,4-dihydropteridin-6-yl)methyl]amino}benzoyl)-L-glutamic acid, pteroyl-L-glutamic acid, vitamin B9, vitamin Bc, vitamin M, folacin, pteroyl-L-glutamate
AHFS/Drugs.com	Monograph
MedlinePlus	a682591
给药途径	By mouth, IM, IV, sub-Q
ATC碼	B03BB01 (WHO) ;
法律規範狀態
法律規範	美：OTC;
藥物動力學數據
生物利用度	50–100%
药物代谢	肝臟
排泄途徑	腎臟
识别信息
	IUPAC命名法 (2S)-2-[[4-[(2-Amino-4-oxo-1H-pteridin-6-yl)methylamino]benzoyl]amino]pentanedioic acid; ;
CAS号	59-30-3
PubChem CID	6037;
IUPHAR/BPS	4563;
DrugBank	DB00158 ;
ChemSpider	5815;
UNII	935E97BOY8;
KEGG	C00504;
ChEBI	CHEBI:27470;
ChEMBL	ChEMBL1622;
CompTox Dashboard（英语：CompTox Chemicals Dashboard） (EPA)	DTXSID0022519 ;
ECHA InfoCard	100.000.381
化学信息
化学式	C19H19N7O6
摩尔质量	441.40 g·mol−1
3D模型（JSmol（英语：JSmol））	交互式图像;
熔点	250 °C（482 °F）（分解）
水溶性	1.6 mg/L (25 °C) mg/mL (20 °C)
	SMILES n1c2C(=O)NC(N)=Nc2ncc1CNc3ccc(cc3)C(=O)N[C@H](C(O)=O)CCC(O)=O;
	InChI InChI=1S/C19H19N7O6/c20-19-25-15-14(17(30)26-19)23-11(8-22-15)7-21-10-3-1-9(2-4-10)16(29)24-12(18(31)32)5-6-13(27)28/h1-4,8,12,21H,5-7H2,(H,24,29)(H,27,28)(H,31,32)(H3,20,22,25,26,30)/t12-/m0/s1; Key:OVBPIULPVIDEAO-LBPRGKRZSA-N;

叶酸（Folate、folic acid）也稱為维生素B₉、维生素M、维生素B_c、蝶酰谷氨酸，屬於維生素B的一種^[4]。葉酸可用於治療由葉酸缺乏症引起的貧血^[4]。葉酸也是孕婦的營養補充品^[4]^[6]。在新生兒的神經管缺損（英语：Neural tube defect）病例中，有超過一半被認為肇因懷孕初期葉酸攝取不足所致^[7]。有超過50個國家利用加入葉酸的營養強化食品來減少神經管缺損的比例^[8]^[9]。長期補充葉酸和中風及心血管疾病風險的小幅下降有關^[10]。葉酸可以口服，也可以用注射的方式補充^[4]。

正常劑量下的葉酸不會造成副作用^[4]，但還不確定長期的高劑量攝取是否有需要關注的問題^[4]。不過已知高劑量的葉酸攝取會讓维生素B12缺乏症的問題較不易被檢查到^[7]。人體在製造DNA、RNA，以及製造细胞分裂需要的胺基酸代謝時，都必須用到葉酸^[7]。因為人體無法自行製造葉酸，因此葉酸屬於人體必需的维生素^[11]。

葉酸攝取不足會造成葉酸缺乏症^[7]，會導致巨母紅血球性貧血（英语：Megaloblastic anemia）^[7]，症狀包括疲勞、心悸、呼吸困难、舌頭上的瘡，以及皮膚或髮色的變化^[7]，兒童若膳食攝入不足，一個月後會出現葉酸缺乏症^[12]。成人體內正常的葉酸總量在10,000–30,000µg，而血液中的濃度則為7 nmol/L（3 ng/mL）^[7]。

葉酸是在1931年至1943年之間發現的^[13]，由米切尔（H．K．Mitchell，1941）及其同事^[14]首次从菠菜叶中提取纯化出来，命名为叶酸^[15]。葉酸列在世界衛生組織基本藥物標準清單中，是基礎公衛體系（英语：health system）中所需，最有效及安全的藥物^[16]。2014年在開發中國家，每一劑的葉酸膳食補充品價格在0.001至0.005美金之間^[17]。葉酸的英文folic源自拉丁文的folium，意思就是葉子^[18]。在許多的食物中都含有葉酸，特別是深綠色的葉菜類以及肝^[7]。

對孕妇的重要性

由于叶酸对于神经管的形成有重要作用，因此孕妇在怀孕前摄入足够的叶酸对于胎儿的正常发育很重要。怀孕期间缺乏叶酸能够影响胎儿神经系统的发育。研究表明在怀孕前期和怀孕中补充足够的叶酸能够降低神经管畸形和唇裂胎儿的出生率^[19]。美国全国环境卫生科学研究所的研究人员在新一期《新英格兰医学杂志》上报告说，孕妇补充叶酸可防婴儿唇裂，但对于预防顎裂作用似乎不太明显^[20]。

自1998年1月1日起，美国已强制规定在某些谷物食品中强化叶酸，FDA规定每1KG谷物食品（面包、面粉、早餐谷物、大米等）强化1.4mg叶酸（美国卫生及公共服务部，1996年）。^[21]

70%接受调查的西班牙孕妇，没有补充叶酸。 ^[22]

叶酸的食物来源

从叶酸最初的提取和名称就能知道，叶酸大量存在于带叶的蔬菜中。菠菜、芦笋、芜菁、小白菜、莴苣、抱子甘蓝、花椰菜、黄豆、玉米、扁豆、豌豆、葵花籽的粗粮及其他带叶的蔬菜。水果包括哈密瓜、蜜瓜、香蕉、木莓、葡萄柚、草莓、以及橙汁、罐装菠萝汁、番茄汁等。动物食品如动物的肝脏、肾脏、禽肉及蛋类，如猪肝、鸡肉、牛肉、羊肉等也含有丰富的叶酸。

每日摄入量

国家卫生部及美国疾病控制中心均给出指导建议：孕妇建议每日摄入量0.4毫克，绝对不能随便选用大剂量的叶酸增补剂。^{[來源請求]}

美國國家醫學院(IOM)建议成年人每日叶酸摄取量安全上限为1毫克，即1000微克。^[23]

叶酸药物要保存在干燥避光阴凉的地方。因为叶酸见水、见光都会分解。 WHO推荐孕妇每日摄入量为：0.4mg/day^[11]

参考文献

引用

^ Fenech, Michael. Folate (vitamin B9) and vitamin B12 and their function in the maintenance of nuclear and mitochondrial genome integrity. Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis. May 2012, 733 (1–2): 21–33. PMID 22093367. doi:10.1016/j.mrfmmm.2011.11.003.
^ Definition of vitamin Bc. Medical-dictionary.thefreedictionary.com. [9 September 2012]. （原始内容存档于2017-09-15）.
^ Darby, William J.; Jones, Edgar. Treatment of Sprue with Synthetic L. casei Factor (Folic Acid, Vitamin M).. Experimental Biology and Medicine. 1 November 1945, 60 (2): 259–262 [13 December 2014]. doi:10.3181/00379727-60-15154P.
^ ^4.0 ^4.1 ^4.2 ^4.3 ^4.4 ^4.5 ^4.6 ^4.7 ^4.8 Folic Acid. Drugs.com. American Society of Health-System Pharmacists. 1 January 2010 [1 September 2016]. （原始内容存档于2017-08-08）.
^ Folic Acid. The PubChem Project. [2017-12-18]. （原始内容存档于2014-04-07）.
^ Bibbins-Domingo, Kirsten; Grossman, David C.; Curry, Susan J.; Davidson, Karina W.; Epling, John W.; García, Francisco A.R.; Kemper, Alex R.; Krist, Alex H.; Kurth, Ann E.; Landefeld, C. Seth; Mangione, Carol M.; Phillips, William R.; Phipps, Maureen G.; Pignone, Michael P.; Silverstein, Michael; Tseng, Chien-Wen. Folic Acid Supplementation for the Prevention of Neural Tube Defects. JAMA. 10 January 2017, 317 (2): 183. doi:10.1001/jama.2016.19438.
^ ^7.0 ^7.1 ^7.2 ^7.3 ^7.4 ^7.5 ^7.6 ^7.7 Dietary supplement fact sheet: Folate. Health Information. Office of Dietary Supplements, US National Institutes of Health. [2016-09-01]. （原始内容存档于2016-09-03）.
^ Bailey, Lynn B. Folate in Health and Disease, Second Edition. CRC Press. 2009: 198 [2017-12-18]. ISBN 9781420071252. （原始内容存档于2021-01-22）（英语）.
^ Obeid, R; Herrmann, W. The emerging role of unmetabolized folic acid in human diseases: myth or reality?. Current drug metabolism. October 2012, 13 (8): 1184–95. PMID 22746304.
^ Li Y, Huang T, Zheng Y, Muka T, Troup J, Hu FB. Folic Acid Supplementation and the Risk of Cardiovascular Diseases: A Meta-Analysis of Randomized Controlled Trials. J Am Heart Assoc. 2016, 5 (8): e003768. PMC 5015297 . PMID 27528407. doi:10.1161/JAHA.116.003768.
^ Pommerville, Glendale Community College Jeffrey C. Alcamo's Fundamentals of Microbiology: Body Systems. Jones & Bartlett Publishers. 2009: 511 [2017-12-18]. ISBN 9780763787127. （原始内容存档于2021-01-22）（英语）.
^ Marino, Bradley S.; Fine, Katie Snead. Blueprints Pediatrics. Lippincott Williams & Wilkins. 2009: 131 [2017-12-18]. ISBN 9780781782517. （原始内容存档于2021-01-22）（英语）.
^ Pond, Wilson G.; Nichols, Buford L.; Brown, Dan L. Adequate Food for All: Culture, Science, and Technology of Food in the 21st Century. CRC Press. 2009: 148. ISBN 9781420077544 （英语）.
^ Mitchell HK, Snell EE, Williams RJ (1941). "The concentration of "folic acid"". J Am Chem Soc. 63 (8): 2284.[doi:10.1021/ja01853a512]
^ Hoffbrand AV & Weir DG (2001) The history of folic acid. Br J Haematol 113, 579-589.
^ WHO Model List of Essential Medicines (19th List) (PDF). World Health Organization. April 2015 [8 December 2016]. （原始内容存档 (PDF)于2016-12-13）.
^ Folic Acid. International Drug Price Indicator Guide. [1 September 2016]. ^{[永久失效連結]}
^ Chambers Concise Dictionary. Allied Publishers. 2004: 451 [2017-12-18]. ISBN 979-8186-06236-3. （原始内容存档于2021-01-06）（英语）.
^ Goh YI & Koren G (2008) Folic acid in pregnancy and fetal outcomes. J Obstet Gynaecol 28, 3-13
^ 存档副本. [2008-08-27]. （原始内容存档于2008-07-25）.
^ 中国营养学会. 《中国居民膳食营养素参考摄入量》. 北京: 中国轻工业出版社. 2006年2月: 356. ISBN 9787501928958 （中文（简体））.
^ El 80% de las mujeres no acuden al médico para planificar el embarazo (新闻稿). EL Pais. September 10, 2013 [2013-10-10]. （原始内容存档于2013-10-15）（西班牙语）.
^ Institute of Medicine (US) Food and Nutrition Board. Dietary Reference Intakes: A Risk Assessment Model for Establishing Upper Intake Levels for Nutrients, Institute of Medicine, 1998. Washington, DC: National Academies Press (US). 1998: 第57页. ISBN 9787501928958 （英语）.

来源

http://www.who.int/elena/titles/guidance_summaries/daily_iron_pregnancy/en/（页面存档备份，存于互联网档案馆）
This article contains information from the public domain resource at http://ods.od.nih.gov/factsheets/Folate-HealthProfessional/（页面存档备份，存于互联网档案馆）
Herbert V. Folic Acid. Shils ME, Olson J, Shike M, Ross AC (编). Modern nutrition in health and disease 9th. Baltimore: Williams and Wilkins. 1999. ISBN 0-683-30769-X.
Food and Nutrition Board, Institute of Medicine. Dietary reference intakes for thiamin, riboflavin, niacin, vitamin B₆, folate, vitamin B₁₂, pantothenic acid, biotin, and choline / a report of the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes and its Panel on Folate, Other B Vitamins, and Choline and Subcommittee on Upper Reference Levels of Nutrients. Washington, D.C.: National Academy Press. 1998. ISBN 0-309-06554-2.
Dietary Guidelines Advisory Committee, Agricultural Research Service, United States Department of Agriculture (USDA). Report of the Dietary Guidelines Advisory Committee on the Dietary Guidelines for Americans, 2010. https://web.archive.org/web/20110317053443/http://www.cnpp.usda.gov/DGAs2010-DGACReport.htm

外部連結

Template:Pauling
Health Canada article about folic acid（页面存档备份，存于互联网档案馆）
Folic Acid Council of Canada
US Public Health Service information page on folic acid（页面存档备份，存于互联网档案馆）
The primary prevention of birth defects: Multivitamins or folic acid?（页面存档备份，存于互联网档案馆）
Folate and Vitamin B12 at Lab Tests Online（页面存档备份，存于互联网档案馆）

生物化學鏈接

Folate biosynthesis (early stages)
Folate biosynthesis (later stages)
Folate coenzymes（页面存档备份，存于互联网档案馆）
C₁ metabolism with folate（页面存档备份，存于互联网档案馆）
Formylation, hydroxymethylation and methylation using folate（页面存档备份，存于互联网档案馆）
IUPAC nomenclature of folate related compounds（页面存档备份，存于互联网档案馆）

[Folate_2011-1] Fenech, Michael. Folate (vitamin B9) and vitamin B12 and their function in the maintenance of nuclear and mitochondrial genome integrity. Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis. May 2012, 733 (1–2): 21–33. PMID 22093367. doi:10.1016/j.mrfmmm.2011.11.003.

[Definition_of_vitamin_Bc-2] Definition of vitamin Bc. Medical-dictionary.thefreedictionary.com. [9 September 2012]. （原始内容存档于2017-09-15）.

[darby1945-3] Darby, William J.; Jones, Edgar. Treatment of Sprue with Synthetic L. casei Factor (Folic Acid, Vitamin M).. Experimental Biology and Medicine. 1 November 1945, 60 (2): 259–262 [13 December 2014]. doi:10.3181/00379727-60-15154P.

[AHFS2016-4] 4.0 ^4.1 ^4.2 ^4.3 ^4.4 ^4.5 ^4.6 ^4.7 ^4.8 Folic Acid. Drugs.com. American Society of Health-System Pharmacists. 1 January 2010 [1 September 2016]. （原始内容存档于2017-08-08）.

[5] Folic Acid. The PubChem Project. [2017-12-18]. （原始内容存档于2014-04-07）.

[USPSTF2017-6] Bibbins-Domingo, Kirsten; Grossman, David C.; Curry, Susan J.; Davidson, Karina W.; Epling, John W.; García, Francisco A.R.; Kemper, Alex R.; Krist, Alex H.; Kurth, Ann E.; Landefeld, C. Seth; Mangione, Carol M.; Phillips, William R.; Phipps, Maureen G.; Pignone, Michael P.; Silverstein, Michael; Tseng, Chien-Wen. Folic Acid Supplementation for the Prevention of Neural Tube Defects. JAMA. 10 January 2017, 317 (2): 183. doi:10.1001/jama.2016.19438.

[NIH2016-7] 7.0 ^7.1 ^7.2 ^7.3 ^7.4 ^7.5 ^7.6 ^7.7 Dietary supplement fact sheet: Folate. Health Information. Office of Dietary Supplements, US National Institutes of Health. [2016-09-01]. （原始内容存档于2016-09-03）.

[8] Bailey, Lynn B. Folate in Health and Disease, Second Edition. CRC Press. 2009: 198 [2017-12-18]. ISBN 9781420071252. （原始内容存档于2021-01-22）（英语）.

[9] Obeid, R; Herrmann, W. The emerging role of unmetabolized folic acid in human diseases: myth or reality?. Current drug metabolism. October 2012, 13 (8): 1184–95. PMID 22746304.

[Li2016-10] Li Y, Huang T, Zheng Y, Muka T, Troup J, Hu FB. Folic Acid Supplementation and the Risk of Cardiovascular Diseases: A Meta-Analysis of Randomized Controlled Trials. J Am Heart Assoc. 2016, 5 (8): e003768. PMC 5015297 . PMID 27528407. doi:10.1161/JAHA.116.003768.

[11] Pommerville, Glendale Community College Jeffrey C. Alcamo's Fundamentals of Microbiology: Body Systems. Jones & Bartlett Publishers. 2009: 511 [2017-12-18]. ISBN 9780763787127. （原始内容存档于2021-01-22）（英语）.

[12] Marino, Bradley S.; Fine, Katie Snead. Blueprints Pediatrics. Lippincott Williams & Wilkins. 2009: 131 [2017-12-18]. ISBN 9780781782517. （原始内容存档于2021-01-22）（英语）.

[13] Pond, Wilson G.; Nichols, Buford L.; Brown, Dan L. Adequate Food for All: Culture, Science, and Technology of Food in the 21st Century. CRC Press. 2009: 148. ISBN 9781420077544 （英语）.

[14] Mitchell HK, Snell EE, Williams RJ (1941). "The concentration of "folic acid"". J Am Chem Soc. 63 (8): 2284.[doi:10.1021/ja01853a512]

[15] Hoffbrand AV & Weir DG (2001) The history of folic acid. Br J Haematol 113, 579-589.

[WHO19th-16] WHO Model List of Essential Medicines (19th List) (PDF). World Health Organization. April 2015 [8 December 2016]. （原始内容存档 (PDF)于2016-12-13）.

[17] Folic Acid. International Drug Price Indicator Guide. [1 September 2016]. ^{[永久失效連結]}

[18] Chambers Concise Dictionary. Allied Publishers. 2004: 451 [2017-12-18]. ISBN 979-8186-06236-3. （原始内容存档于2021-01-06）（英语）.

[19] Goh YI & Koren G (2008) Folic acid in pregnancy and fetal outcomes. J Obstet Gynaecol 28, 3-13

[20] 存档副本. [2008-08-27]. （原始内容存档于2008-07-25）.

[21] 中国营养学会. 《中国居民膳食营养素参考摄入量》. 北京: 中国轻工业出版社. 2006年2月: 356. ISBN 9787501928958 （中文（简体））.

[22] El 80% de las mujeres no acuden al médico para planificar el embarazo (新闻稿). EL Pais. September 10, 2013 [2013-10-10]. （原始内容存档于2013-10-15）（西班牙语）.

[23] Institute of Medicine (US) Food and Nutrition Board. Dietary Reference Intakes: A Risk Assessment Model for Establishing Upper Intake Levels for Nutrients, Institute of Medicine, 1998. Washington, DC: National Academies Press (US). 1998: 第57页. ISBN 9787501928958 （英语）.

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