*此篇條目的引言在中文已有資料，但並不是由英文翻譯而來，故有許多需要整合的地方（參考來源也需要整理）。我先把在中文條目中已經有的段落剪貼過來，以方便後續合併：
Malnutrition is a condition that results from eating a diet in which nutrients are not enough or are too much such that it causes health problems.[1][2] The nutrients involved can include: calories, protein, carbohydrates, vitamins or minerals.[2] It is often used specifically to refer to undernutrition where there is not enough calories, protein or micronutrients; however, it also includes overnutrition.[3][4] If undernutrition occurs during either pregnancy or before the age of two years of age it may result in permanent problems with physical and mental development.[2] Extreme undernourishment, known as starvation, may have symptoms that include: a short height, thin body, very poor energy levels, and swollen legs and abdomen.[2][3] People also often get infections and are frequently cold. The symptoms of micronutrient deficiencies depend on the micronutrient that is lacking.[3]
’’’營養不良’’’（{{lang-en|malnutrition}}）是一個描述[[健康]]狀況的用語，是指由不平衡[[飲食]]所造成的[[營養素]]缺乏、過剩、或比例失調<ref>{{DorlandsDict|five/000062745|malnutrition}}</ref><ref name=FFL2010>{{cite book|first1=UNICEF|title=Facts for life|date=2010|publisher=United Nations Children’s Fund|location=New York|isbn=978-92-806-4466-1|pages=61 and 75|edition=4th ed.|url=http://www.unicef.org/nutrition/files/Facts_for_Life_EN_010810.pdf}}</ref>。重要的營養成分包括：產生[[熱量]]的[[蛋白質]]、脂質與[[醣類]]，還有不產生熱量的[[維生素]]與[[膳食礦物質]]<ref name=FFL2010/>。一般會用「營養不良」指稱’’’營養不足’’’，也就是攝取的熱量、蛋白質與[[微量元素]]不足，但{{link-en|營養過剩|Overnutrition}}也屬於營養不良的一種<ref name=Young2012>{{cite book|last1=Young|first1=E.M.|title=Food and development|date=2012|publisher=Routledge|location=Abingdon, Oxon|isbn=9781135999414|pages=36–38|url=http://books.google.ca/books?id=XhwKwNzJVjQC&pg=PA36}}</ref><ref name=Jones2011>{{cite book|title=Essentials of International Health|date=2011|publisher=Jones & Bartlett Publishers|isbn=9781449667719|page=194|url=http://books.google.ca/books?id=lt7TqZPZSlIC&pg=PA194}}</ref>。若是孕婦在[[妊娠|懷孕]]時或兒童在兩歲以前發生營養不足，可能會對兒童的身心發展造成永久性的損傷<ref name=FFL2010/>。極度的營養不足稱之為[[餓死|饑饉]]，處在饑饉狀態的人可能會有身高偏低、體型瘦弱、活力不佳、腿部及[[腹|腹部]]腫脹的情形<ref name=FFL2010/><ref name=Young2012/>，也容易受到疾病感染且[[低體溫症|不耐寒冷]]，而{{link-en|微量元素缺乏|Micronutrient deficiency}}產生的症狀則視缺乏的元素而各有不同。如果不能長期攝取由適當數量、種類或質量的營養素所構成的健康飲食，個體將產生營養不良。長期的營養不良可能導致飢餓死亡<ref name=Young2012/>。
Undernourishment is most often due to not enough high quality food available to eat.[5] This is often related to high food prices and poverty.[2][5] A lack of breast feeding may contribute, as may a number of infectious diseases such as: gastroenteritis, pneumonia,malaria and measles which increase nutrient requirements.[5] There are two main types of undernutrition: protein-energy malnutrition and dietary deficiencies.[4] Protein-energy malnutrition has two severe forms: marasmus (a lack of protein and calories) andkwashiorkor (a lack of just protein).[3] Common micronutrient deficiencies include: a lack of iron, iodine and vitamin A.[3] During pregnancy, due to increased demand, deficiencies become more common.[6] In some developing countries overnutrition in the form of obesity is beginning to present within the same communities as undernutrition.[7] Other causes of malnutrition include anorexia nervosa and bariatric surgery.[8][9] In the elderly malnutrition becomes more common due to physical, psychological and social factors.[10]
世界上大部分的營養不良都是營養不足造成，由於貧困與相對高昂的食物價格<ref name=FFL2010/><ref name=WHO2014/>，導致無法攝入足夠的食物<ref name=WHO2014/>。除此之外缺乏[[母乳餵養]]也可能會造成嬰兒營養不足，而部分[[感染|感染疾病]]如[[腸胃炎]]、[[肺炎]]、[[瘧疾]]與[[痲疹]]，會造成人體熱量需求上升，也可能引起營養不足<ref name=WHO2014/>。營養不足主要可分為兩大類：{{link-en|蛋白質能量營養不良|Protein-energy malnutrition}}與微量元素缺乏<ref name=Jones2011/>。蛋白質能量營養不良又有幾種常見型態：因同時缺乏蛋白質和熱量而產生的{{link-en|消瘦症|Marasmus}}與單純缺乏蛋白質產生的[[誇休可爾症|紅孩症]]<ref name=Young2012/>；飲食成份中常缺乏的微量元素包括[[缺鐵|鐵]]、[[碘缺乏病|碘]]與{{link-en|維生素A缺乏|Vitamin A deficiency|維生素A}}<ref name=Young2012/>。孕婦對營養的需求會增加，因此在[[妊娠|懷孕]]期間營養不足更容易發生<ref>{{cite book|last1=Konje|first1=editor, Mala Arora ; co-editor, Justin C.|title=Recurrent pregnancy loss|date=2007|publisher=Jaypee Bros. Medical Publishers|location=New Delhi|isbn=9788184480061|edition=2nd ed.}}</ref>。在某些開發中國家，[[肥胖症]]不僅是營養過剩的表現，營養不足亦能造成[[肥胖症]]<ref>{{cite web|title=Progress For Children: A Report Card On Nutrition|url=http://www.unicef.org/nutrition/files/Progress_for_Children_-_No._4.pdf|publisher=UNICEF}}</ref>。其他可能引起營養不足的狀況包括[[神经性厌食症]]與[[減肥手術]]<ref>{{cite book|last1=Prentice|first1=editor-in-chief, Benjamin Caballero ; editors, Lindsay Allen, Andrew|title=Encyclopedia of human nutrition|date=2005|publisher=Elsevier/Academic Press|location=Amsterdam|isbn=9780080454283|page=68|edition=2nd ed.|url=http://books.google.ca/books?id=DHtERWm0mrcC&pg=RA1-PA68}}</ref><ref>{{cite book|title=Stoelting’s anesthesia and co-existing disease|date=2012|publisher=Saunders/Elsevier|location=Philadelphia|isbn=9781455738120|page=324|edition=6th ed.|url=http://books.google.ca/books?id=yxTtmJYPUV0C&pg=PA324}}</ref>，[[老年]]人則常因為生理、心理或社會因素而發生營養不良<ref>{{cite book|last1=editors|first1=Ronnie A. Rosenthal, Michael E. Zenilman, Mark R. Katlic,|title=Principles and practice of geriatric surgery|date=2011|publisher=Springer|location=Berlin|isbn=9781441969996|page=78|edition=2nd ed.|url=http://books.google.ca/books?id=VcgmpMZE6a8C&pg=PA87}}</ref>。
Efforts to improve nutrition are some of the most effective forms of development aid.[11] Breastfeeding can reduce rates of malnutrition and death in children,[2] and efforts to promote the practice increase rates.[12] In young children providing food in addition to breastmilk between six months and two years improves outcomes.[12] There is also good evidence supporting the supplementation of a number of micronutrients during pregnancy and among young children in the developing world.[12] To get food to people who need it most both delivering food and providing money so that people can buy food within local markets are effective.[11][13] Simply feeding people at school is insufficient.[11] Management of severe malnutrition within the person’s home with ready-to-use therapeutic foods is possible much of the time.[12] In those who have severe malnutrition complicated by other health problems treatment within hospital is recommended.[12] This often involves managing low blood sugar, body temperature, dehydration, and gradual feeding.[12][14] Routineantibiotics are usually recommended due to the high risk of infection.[14] Long term measures include: improving agricultural practices,[15] reducing poverty, improving sanitation, and the empowerment of women.[11]
改善[[營養學|營養]]為[[發展援助]]中部分最有效的方式之一<ref name=UK2012/>。母乳哺餵可減少孩童的營養不良及死亡<ref name=FFL2010/>，並有效推進存活率<ref name=Bh2013/>。除母乳外，提供其他食物給6個月至2歲大的孩童，可改善營養不良<ref name=Bh2013/>。另外有良好證據，支持提供發展中國家懷孕過程中的孕婦與孩童，補充含微量元素的[[膳食補充劑]]<ref name=Bh2013/>。讓亟需的人取得食物之最佳方法為提供食品或給予金錢於當地市場購買<ref name=UK2012/><ref>{{cite web|title=World Food Programme, Cash and Vouchers for Food|url=http://documents.wfp.org/stellent/groups/public/documents/communications/wfp246176.pdf|website=WFP.org|accessdate=5 July 2014|date=April 2012}}</ref>，然而僅提供食物給學童是不夠的<ref name=UK2012/>。大部分嚴重營養不良的都能以{{link-en|即食治療食品|Therapeutic_food#Ready-to-Use_Therapeutic_Food}}處理<ref name=Bh2013/>。當營養不良併發其他健康問題時，則建議進一步就醫治療<ref name=Bh2013/>。這些常包括處理{{link-en|低血糖|Hypoglycemia}}、[[低體溫症|體溫]]、[[脫水]]以及漸進式餵食<ref name=Bh2013/><ref name=WHO2003>{{cite book|first1=World Health Organization. Authors: Ann Ashworth|title=Guidelines for the inpatient treatment of severely malnourished children|date=2003|publisher=World Health Organization|location=Geneva|isbn=9241546093}}</ref>。基於感染之高風險，通常建議例行性給予[[抗生素]]<ref name=WHO2003/>。而解決營養不良的長期措施，包括提升農業技術<ref name=solcultivateplanet>{{cite journal |author=Jonathan A. Foley, Navin Ramankutty, Kate A. Brauman, Emily S. Cassidy, James S. Gerber, Matt Johnston, Nathaniel D. Mueller, Christine O’Connell, Deepak K. Ray, Paul C. West, Christian Balzer, Elena M. Bennett, Stephen R. Carpenter, Jason Hill1, Chad Monfreda, Stephen Polasky1, Johan Rockström, John Sheehan, Stefan Siebert, David Tilman1, David P. M. Zaks |title=Solutions for a cultivated planet |journal=Nature |volume=478 |issue=7369 |pages=337–342 |date=October 2011|pmid=21993620|url=http://www.nature.com/nature/journal/v478/n7369/full/nature10452.html |doi=10.1038/nature10452}}</ref>、降低貧窮、改善{{link-en|衛生條件|Sanitation}}和{{link-en|賦權|Empowerment#Women|女性賦權}}<ref name=UK2012/>。
[[世界衛生組織]]（WHO）認為營養不良是世界公共衛生狀況的最大威脅。[6] 改善[[營養]]被廣泛接受為最有效的援助方式。[6][7]營養干預手段被直接用來針對因營養不足所造成的後果，已經被證明是所有發展干預手段中效果最好的手段。[8]這些緊急措施中包括有通過[[食品強化]]或直接的[[膳食補充劑]]來補充缺乏的[[微量元素]]。[9][10] WHO，[[UNICEF]]和[[世界糧食計劃署]]推薦使用[[醫療食品]]來管理社區性的嚴重急性營養缺乏，這類食品在緊急措施中會導致體重增加。[11]經常被援助組織使用的[[飢荒救濟]]模式來進行呼籲，不要直接從援助國購買食物，而是將發放現金或代幣券給飢餓者，支付給受援助國的當地農民購買食物，以避免（援助物資）[[傾銷]]損害當地農民。[12][13]
長期的措施包括藉由提高產量來促進高營養價值的農業，並且使未來會使產量降低的可能性降到最低。[14]其他的作法還包括幫助農民，[15]不過[[世界銀行]]限制政府對農民的補貼，而化肥的使用可能會對生態系和人類的健康造成負面影響[16][17]，因此受到很多公民團體的阻礙。[18]
營養不良已經成為婦女，兒童和老年人的關注問題。由於懷孕和哺乳，婦女需要更多的營養。[19]兒童甚至在出生前就有營養不良的危險，因為他們的營養狀況直接和他們母親的營養狀況相聯繫。[20]哺乳可以減少兒童的營養不良率和死亡率，[4][11]針對母親們的教育計劃可以對這些比例產生很大影響。[21]老年人因為特有的複雜性（比如胃口和精力的改變，咀嚼和吞咽的問題）會有很大的機會造成營養不良。[22]充分的老年看護是防止營養不良的基本手段，特別是對那些不能自理的老年人來說。
There were 925 million undernourished people in the world in 2010, an increase of 80 million since 1990.[16][17] Another billion people are estimated to have a lack of vitamins and minerals.[11] In 2010 protein-energy malnutrition was estimated to have resulted in 600,000 deaths down from 883,000 deaths in 1990.[18] Other nutritional deficiencies, which include iodine deficiency and iron deficiency anemia, result in another 84,000 deaths.[18] Undernutrition as of 2010 was the cause of 1.4% of all disability adjusted life years.[11][19] About a third of deaths in children are believed to be due to undernutrition; however, the deaths are rarely labelled as such.[5] In 2010 it was estimated to have contributed to about 1.5 million deaths in women and children[20] though some estimate the number may be greater than 3 million.[12] An additional 165 million children havestunted growth from the disease.[12] Undernutrition is more common in developing countries.
2010年，全球共有9.25億人營養不良，並自1990年起，營養不良人數從1990年至今增加了8,000萬人<ref name=FAO2010>{{cite web|title=Global hunger declining, but still unacceptably high International hunger targets difficult to reach|url=http://www.fao.org/docrep/012/al390e/al390e00.pdf|website=Food and Agriculture Organization of the United Nations|accessdate=1 July 2014|date=September 2010}}</ref><ref name=Fao2008>{{cite book|last1=Food|last2=(FAO)|first2=Agriculture Organization of the United Nations|title=The state of food insecurity in the world, 2008 : high food prices and food security : threats and opportunities|date=2008|publisher=Food and Agriculture Organization of the United Nations (FAO)|location=Rome|isbn=978-92-5-106049-0|page=2|url=http://www.fao.org/docrep/011/i0291e/i0291e00.htm|quote=FAO’s most recent estimates put the number of hungry [actually, malnourished] people at 923 million in 2007, an increase of more than 80 million since the 1990–92 base period.}}</ref>。此外，約10億人可能缺乏維生素與礦物質<ref name=UK2012>{{cite web|title=An update of ‘The Neglected Crisis of Undernutrition: Evidence for Action’|url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/67319/undernutrition-finalevidence-oct12.pdf|website=www.gov.uk|publisher=Department for International Development|accessdate=5 July 2014|date=Oct 2012}}</ref>。2010年，{{link-en|蛋白質能量營養不良|Protein-energy malnutrition}}估計造成60萬人死亡，比起1990年時造成88.3萬人死亡來說，有所降低<ref name=Loz2012/>。其他營養不良的情形，包含了[[碘缺乏病]]與{{link-en|缺鐵性貧血|Iron-deficiency anemia}}，造成8.4萬人死亡<ref name=Loz2012>{{cite journal |author=Lozano R, Naghavi M, Foreman K, et al. |title=Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010 |journal=Lancet |volume=380 |issue=9859 |pages=2095–128 |date=December 2012 |pmid=23245604 |doi=10.1016/S0140-6736(12)61728-0 |url=}}</ref>。2010年，營養不良造成[[失能調整生命年]]成長了1.4%<ref name=UK2012/><ref name=Murray2012>{{cite journal|last1=Murray|first1=CJ|tit
le=Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010.|journal=Lancet|date=Dec 15, 2012|volume=380|issue=9859|pages=2197–223|pmid=23245608|doi=10.1016/S0140-6736(12)61689-4}}</ref>。據信營養不良為兒童死亡起因的1/3，然而此部分卻很少被提及<ref name=WHO2014>{{cite web|title=Maternal, newborn, child and adolescent health|url=http://www.who.int/maternal_child_adolescent/topics/child/malnutrition/en/|website=WHO|accessdate=4 July 2014}}</ref>。2010年，估計已造成150萬兒童與婦女死於營養不良<ref name=Lim2012>{{cite journal |author=Lim SS, Vos T, Flaxman AD, et al. |title=A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010 |journal=Lancet |volume=380 |issue=9859 |pages=2224–60 |date=December 2012 |pmid=23245609 |doi=10.1016/S0140-6736(12)61766-8 |url=}}</ref>，而部分估計可能超過300萬<ref name="Bh2013"/>。此外，有1.65
億兒童有疾病導致的{{link-en|發育遲緩|Stunted growth}}。營養不良於[[開發中國家]]更為常見<ref name=Bh2013>{{cite journal|last1=Bhutta|first1=ZA|last2=Das|first2=JK|last3=Rizvi|first3=A|last4=Gaffey|first4=MF|last5=Walker|first5=N|last6=Horton|first6=S|last7=Webb|first7=P|last8=Lartey|first8=A|last9=Black|first9=RE|last10=Lancet Nutrition Interventions Review|first10=Group|last11=Maternal and Child Nutrition Study|first11=Group|title=Evidence-based interventions for improvement of maternal and child nutrition: what can be done and at what cost?|journal=Lancet|date=Aug 3, 2013|volume=382|issue=9890|pages=452–77|pmid=23746776|doi=10.1016/s0140-6736(13)60996-4}}</ref> Undernutrition is more common in [[developing countries]].<ref>{{cite book|author1=Liz Young|title=World Hunger Routledge Introductions to Development|date=2002|isbn=9781134774944|page=20|url=http://books.google.ca/books?id=w4CGAgAAQBAJ&pg=PA20}}</ref>
{{TOC limit|3}}。