{{for|the plant disorder also known as "lime-induced chlorosis"|Iron deficiency (plant disorder)}}

{{Infobox disease|

Name = Iron deficiency |

Image = Heme b.svg |

Caption = [[Iron]] in [[heme]] |

DiseasesDB = 6947 |

ICD10 = {{ICD10|E|61|1|e|50}} |

ICD9 = {{ICD9|280.9}} |

ICDO = |

OMIM = |

MedlinePlus = 000584 |

eMedicineSubj = med |

eMedicineTopic = 1188 |

MeshID = |

}}

'''Iron deficiency''' ('''sideropenia''' or '''hypoferremia''') is one of the most common of the [[nutritional deficiencies]]. [[Iron]] is present in all [[cell (biology)|cell]]s in the [[human body]], and has several vital functions. Examples include as a carrier of [[oxygen]] to the tissues from the [[human lung|lung]]s in the form of [[hemoglobin]], as a transport medium for electrons within the cells in the form of [[cytochrome]]s, and as an integral part of [[enzyme]] reactions in various tissues. Too little iron can interfere with these vital functions and lead to [[morbidity]] and [[death]].

The eventual consequence of iron deficiency is [[iron deficiency anemia]] where the body's stores of iron have been depleted and the body is unable to maintain levels of haemoglobin in the blood. Children and [[pre-menopausal]] women are the groups most prone to the disease.

Total body iron averages approximately 3.8 g in men and 2.3 g in women. In [[blood plasma]], iron is carried tightly bound to the protein [[transferrin]]. There are several mechanisms that control [[human iron metabolism]] and safeguard against iron deficiency. The main regulatory mechanism is situated in the gastrointestinal tract. When loss of iron is not sufficiently compensated by adequate intake of iron from the diet, a state of iron deficiency develops over time. When this state is uncorrected, it leads to iron deficiency anemia.

==Causes==

* chronic bleeding ([[haemoglobin]] contains iron)

** excessive [[menstrual bleeding]]

** non-menstrual [[bleeding]]

** bleeding from the [[gastrointestinal tract]] ([[Peptic ulcer|ulcers]], [[hemorrhoid]]s, [[Ulcerative Colitis]] etc.)

** rarely, [[laryngological]] bleeding or from the [[respiratory tract]]

* inadequate intake

* substances (in diet or drugs) interfering with iron absorption

* [[malabsorption]] syndromes

* [[inflammation]] where it is [[Evolutionary medicine|adaptive]] to limit bacterial growth

* blood donation

Though [[genetic defects]] causing iron deficiency have been studied in rodents, there are no known genetic disorders of [[human iron metabolism]] that directly cause iron deficiency.

==Symptoms==

Symptoms of iron deficiency can occur even before the condition has progressed to [[iron deficiency anaemia]].

Symptoms of iron deficiency are not unique to iron deficiency (i.e. not [[pathognomonic]]). Iron is needed for many enzymes to function normally, so a wide range of symptoms may eventually emerge, either as the secondary result of the anemia, or as other primary results of iron deficiency. Symptoms of iron deficiency include:

* [[Fatigue (physical)|fatigue]]

* [[dizziness]]

* [[pallor]]

* [[hair loss]]

* [[Myoclonus|Twitches]]

* [[irritability]]

* [[Muscle weakness|weakness]]

* [[Pica (disorder)|pica]]

* [[Brittle nails|brittle]] or [[Nail_disease#Shape_and_texture|grooved nails]]

* [[Plummer-Vinson syndrome]]: painful atrophy of the [[mucous membrane]] covering the [[tongue]], the [[human pharynx|pharynx]] and the [[esophagus]]

* impaired [[immune function]]<ref>{{Cite PMID|17726308}}</ref>

*[[pagophagia]]

*[[restless legs syndrome]]<ref name="pmid17368978">{{cite journal |pmid=17368978 |year= April 2007 |title=Restless legs syndrome in Indian patients having iron deficiency anemia in a tertiary care hospital |last1=Rangarajan |first1=Sunad |last2=D'Souza |first2=George Albert.|journal=Sleep Medicine. |volume= 8 |issue=3 |pages=247–51 |doi=10.1016/j.sleep.2006.10.004}}</ref>

==Likely lab test results in people with iron deficiency==

* A [[complete blood count]] would likely reveal [[microcytic anemia]]<ref>{{cite book

| last = Longmore

| first = Murray

| coauthors = Ian B. Wilkinson, Supaj Rajagoplan

| title = Oxford Handbook of Clinical Medicine|edition= 6th

| publisher = [[Oxford University Press]]

| year = 2004

| pages = 626–628

| isbn = 0-19-852558-3 }}</ref>

* Low serum [[ferritin]] ''*see below''

* Low [[serum iron]]

* High [[TIBC]] (total iron binding capacity)

* It is possible that the [[fecal occult blood]] test might be positive, if iron deficiency is the result of [[gastrointestinal bleeding]].

As always, laboratory values have to be interpreted with the lab's [[reference values]] in mind and considering all aspects of the individual clinical situation.

Serum ferritin can be elevated in inflammatory conditions and so a normal serum ferritin may not always exclude iron deficiency, and the utility is improved by taking a concurrent C reactive protein (CRP).

==Consequences==

Continued iron deficiency may progress to [[anaemia]] and worsening fatigue. [[Thrombocytosis]], or an elevated [[platelet]] count, can also result. A lack of sufficient iron levels in the blood is a reason that some people cannot donate blood.

==Treatment==

Before commencing treatment, there should be definitive diagnosis of the underlying cause for iron deficiency. This is particularly the case in older patients, who are most susceptible to [[colorectal cancer]] and the gastrointestinal bleeding it often causes. In adults, 60% of patients with iron deficiency anemia may have underlying gastrointestinal disorders leading to chronic blood loss.<ref name="pmid8179652">{{cite journal |author=Rockey D, Cello J |title=Evaluation of the gastrointestinal tract in patients with iron-deficiency anemia |journal=N Engl J Med |volume=329 |issue=23 |pages=1691–5 |year=1993 |pmid=8179652 |doi=10.1056/NEJM199312023292303}}</ref>

It is likely that the cause of the iron deficiency will need treatment as well.

Upon diagnosis, the condition can be treated with [[iron supplements]]. The choice of supplement will depend upon both the severity of the condition, the required speed of improvement (e.g. if awaiting elective surgery) and the likelihood of treatment being effective (e.g. if has underlying [[IBD]], undergoing [[dialysis]] or is having [[ESA]] therapy).

Examples of oral iron that are often used are [[ferrous sulfate]], [[ferrous gluconate]], or amino acid chelate tablets. Recent research suggests the replacement dose of iron, at least in the elderly with iron deficiency, may be as little as 15&nbsp;mg per day of elemental iron.<ref name="pmid16194646">{{cite journal |author=Rimon E, Kagansky N, Kagansky M, Mechnick L, Mashiah T, Namir M, Levy S |title=Are we giving too much iron? Low-dose iron therapy is effective in octogenarians |journal=Am J Med |volume=118 |issue=10 |pages=1142–7 |year=2005 |pmid=16194646 | doi = 10.1016/j.amjmed.2005.01.065}}</ref>

==Food sources of iron==

Mild iron deficiency can be prevented or corrected by eating iron-rich foods and by cooking in an iron skillet. Because iron is a requirement for most plants and animals, a wide range of foods provide iron. Good sources of dietary iron have haem-iron as this is most easily absorbed and is not inhibited by medication or other dietary components. Three examples are [[red meat]], [[poultry]] and [[entomophagy|insects]].<ref>Defoliart,G. 1992. Insects as Human Food. Crop Protection, 11:395-99.</ref><ref>Bukkens SGF. 1997. The Nutritional Value of Edible Insects. Ecol. Food. Nutr. Vol. 36(2–4): pp. 287–319.</ref> Non-haeme sources do contain iron, though it has reduced bioavailability. Examples are [[lentil]]s, [[bean]]s, [[leafy vegetable]]s, [[pistachio]]s, [[tofu]], fortified bread, and fortified breakfast cereals.

Iron from different foods is absorbed and processed differently by the body; for instance, iron in meat (heme iron source) is more easily absorbed than iron in grains and vegetables ("non-heme" iron source),<ref>[http://www.eatwell.gov.uk/healthissues/irondeficiency/ Iron deficiency]. Food Standards Agency.</ref> but [[heme]]/[[hemoglobin]] from red meat has effects which may increase the likelihood of [[colorectal cancer]].<ref name="pmid10582688">{{cite journal |author=Sesink AL, Termont DS, Kleibeuker JH, Van der Meer R |title=Red meat and colon cancer: the cytotoxic and hyperproliferative effects of dietary heme |journal=[http://cancerres.aacrjournals.org/ Cancer Research] |volume=59 |issue=22 |pages=5704–9 |year=1999 |pmid=10582688 |doi= |url=http://cancerres.aacrjournals.org/cgi/pmidlookup?view=long&pmid=10582688}}</ref><ref name="pmid16226281">{{cite journal |author=Glei M, Klenow S, Sauer J, Wegewitz U, Richter K, Pool-Zobel BL |title=Hemoglobin and hemin induce DNA damage in human colon tumor cells HT29 clone 19A and in primary human colonocytes |journal=[[Mutat. Res.]] |volume=594 |issue=1–2 |pages=162–71 |year=2006 |pmid=16226281 |doi=10.1016/j.mrfmmm.2005.08.006 |url=}}</ref> Minerals and chemicals in one type of food may also inhibit absorption of iron from another type of food eaten at the same time.<ref>[http://www.nlm.nih.gov/medlineplus/ency/article/002422.htm Iron in diet]. MedlinePlus.</ref> For example, [[oxalate]]s and [[phytic acid]] form insoluble complexes which bind iron in the gut before it can be absorbed.

Because iron from plant sources is less easily absorbed than the heme-bound iron of animal sources, [[vegetarian]]s and [[vegan]]s should have a somewhat higher total daily iron intake than those who eat meat, fish or poultry.<ref>[[Reed Mangels|Mangels, Reed]]. [http://www.vrg.org/nutrition/iron.htm Iron in the vegan diet]. The Vegetarian Resource Group.</ref> [[Legume]]s and dark-green leafy vegetables like [[broccoli]], [[kale]] and oriental greens are especially good sources of iron for vegetarians and vegans. However, [[spinach]] and [[Swiss chard]] contain oxalates which bind iron making it almost entirely unavailable for absorption. Iron from nonheme sources is more readily absorbed if consumed with foods that contain either heme-bound iron or [[vitamin C]]. This is due to a hypothesised "meat factor" which enhances iron absorption.<ref>[http://www.merckmanuals.com/home/disorders_of_nutrition/minerals/iron.html Iron]. The Merck Manuals Online Medical Library.</ref>

Following are two tables showing the richest foods in heme and non-heme iron.<ref>[http://iron.rich-foods.com/ iron rich foods]. Rich Foods.</ref>

In both tables, foods serving size may differ from the usual 100g quantity for relevancy reasons.

Arbitrarily, the guideline is set to 18&nbsp;mg, which is the [[usda|USDA]] [[Recommended Dietary Allowance]] for women aged between 19 and 50.<ref>[http://www.iom.edu/Activities/Nutrition/SummaryDRIs/~/media/Files/Activity%20Files/Nutrition/DRIs/5_Summary%20Table%20Tables%201-4.pdf Dietary Reference Intakes: Recommended Intakes for Individuals] National Academy of Sciences. Institute of Medicine. Food and Nutrition Board.</ref>

{| class="wikitable"

|+Abstract: richest foods in ''heme iron''

|-

!Food

!Serving Size

!Iron

!% Guideline

|-

|[[clam]]

|align="right" |100g

|align="right" |28&nbsp;mg

|align="right" |155%

|-

|[[Pork|pork liver]]

|align="right" |100g

|align="right" |18&nbsp;mg

|align="right" |100%

|-

|[[lamb and mutton|lamb kidney]]

|align="right" |100g

|align="right" |12&nbsp;mg

|align="right" |69%

|-

|[[oyster|cooked oyster]]

|align="right" |100g

|align="right" |12&nbsp;mg

|align="right" |67%

|-

|[[cuttlefish]]

|align="right" |100g

|align="right" |11&nbsp;mg

|align="right" |60%

|-

|[[lamb and mutton|lamb liver]]

|align="right" |100g

|align="right" |10&nbsp;mg

|align="right" |57%

|-

|[[octopus]]

|align="right" |100g

|align="right" |9.5&nbsp;mg

|align="right" |53%

|-

|[[mussel]]

|align="right" |100g

|align="right" |6.7&nbsp;mg

|align="right" |37%

|-

|[[beef|beef liver]]

|align="right" |100g

|align="right" |6.5&nbsp;mg

|align="right" |36%

|-

|[[beef|beef heart]]

|align="right" |100g

|align="right" |6.4&nbsp;mg

|align="right" |35%

|}

{| class="wikitable"

|+Abstract: richest foods in ''non-heme iron''

|-

!Food

!Serving Size

!Iron

!% Guideline

|-

|[[soybean]]s

|align="right" |250ml

|align="right" |9.3&nbsp;mg

|align="right" |52%

|-

|[[bean|raw yellow beans]]

|align="right" |100g

|align="right" |7&nbsp;mg

|align="right" |39%

|-

|[[lentil]]s

|align="right" |250ml

|align="right" |7&nbsp;mg

|align="right" |39%

|-

|[[falafel]]

|align="right" |140g

|align="right" |4.8&nbsp;mg

|align="right" |27%

|-

|[[soybean|soybean kernels]]

|align="right" |250ml

|align="right" |4.7&nbsp;mg

|align="right" |26%

|-

|[[sesame|toasted sesame seeds]]

|align="right" |30g

|align="right" |4.4&nbsp;mg

|align="right" |25%

|-

|[[Spirulina (dietary supplement)|spirulina]]

|align="right" |15g

|align="right" |4.3&nbsp;mg

|align="right" |24%

|-

|[[ginger|candied ginger root]]

|align="right" |30g

|align="right" |3.4&nbsp;mg

|align="right" |19%

|-

|[[spinach]]

|align="right" |85g

|align="right" |3&nbsp;mg

|align="right" |17%

|}

Iron deficiency can have serious health consequences that diet may not be able to quickly correct, hence an [[iron supplement]] is often necessary if the iron deficiency has become symptomatic.

==Bioavailability and bacterial infection==

Iron is needed for [[bacterial growth]] making its [[bioavailability]] an important factor in controlling [[infection]].<ref>{{Cite PMID|760197}}</ref> [[Blood plasma]] as a result carries iron tightly bound to [[transferrin]], and only releases it to cells with appropriate cell markers thus preventing its access to bacteria.<ref name=Nesse30>Nesse, R. M.; Williams, G. C. ''Why We Get Sick: The New Science of Darwinian Medicine''. New York. page 30 ISBN 0-679-74674-9.</ref> Between 15 and 20 percent of the protein content in [[human milk]] consists of [[lactoferrin]]<ref>T. William Hutchens, Bo Lönnerdal; Lactoferrin: Interactions and Biological Functions (1997). [http://books.google.com/books?id=KOHK0Zi8S08C&pg=PA379&vq=milk&source=gbs_search_s&cad=0 page 379 on Google Books]</ref> that binds iron. As a comparison, in cow's milk, this is only 2 percent. As a result, [[Breast feeding|breast fed babies]] have fewer infections.<ref name=Nesse30/> Lactoferrin is also concentrated in tears, saliva and at wounds to bind iron to limit bacterial growth. [[Egg white]] contains 12% [[conalbumin]] to withhold it from bacteria that get through the egg shell (for this reason prior to antibiotics, egg white was used to treat infections).<ref>Nesse, R. M.; Williams, G. C. ''Why We Get Sick: The New Science of Darwinian Medicine''. New York. page 29 ISBN 0-679-74674-9.</ref>

To reduce bacterial growth, plasma concentrations of iron are lowered in inflammatory states in the body, such as those caused by [[fever]],<ref>{{Cite PMID|6420813}}</ref> and following surgery after open wounds where it acts as a protection against infection.<ref>{{Cite PMID|6830068}}</ref> Reflecting this link between iron bioavailability and bacterial growth, the taking of [[iron supplements]] can increase the risk of infection.<ref>{{Cite PMID|361162}}</ref> A moderate iron deficiency, in contrast, can provide protection against acute infection.<ref>{{Cite PMID|18949769}}</ref> This is due to the release of [[hepcidin]] from the liver.

==References==

{{reflist|2}}

==Further reading==

*{{Cite book |year=2009 |author=Gropper, Sareen S |author2=Smith, Jack L |author3=Groff, James L |chapter=Enhancers and inhibitors of iron absorption |chapterurl=http://books.google.com/books?id=rXSO9YLr72YC&pg=PA474&dq=iron+absorption+inhibitors+oxalate#v=onepage&q=iron%20absorption%20inhibitors%20oxalate&f=false |editor=. |title=Advanced Nutrition and Human Metabolism |edition=5th |place=Belmont, California |publisher=[[Cengage Learning|Wadsworth, Cengage Learning]] |isbn=978-0-495-11657-8 |url=http://books.google.com/books?id=rXSO9YLr72YC&printsec=frontcover&dq=Advanced+nutrition#v=onepage&q&f=false |accessdate=2 October 2010 |postscript=&nbsp;&nbsp;Alternative ISBN 0-495-11657-2}}

*{{Cite journal |year=2005 |author=Umbreit, Jay |title=Iron Deficiency: A Concise Review |journal=[[American Journal of Hematology]] |volume=78 |pages=225–231 |url=http://www.idpas.org/pdf/4145.pdf |accessdate=2 October 2010 |doi=10.1002/ajh.20249 |issue=3 |postscript=<!-- Bot inserted parameter. Either remove it; or change its value to "." for the cite to end in a ".", as necessary. -->{{inconsistent citations}}}}

*{{Cite journal |date=April 1989 |author=Hobbs, Christopher |title='Iron-Clad' Foods and Herbs |url=http://books.google.com/books?id=iAcAAAAAMBAJ&pg=PA70&dq=%22when+i%22+iron+hobbs#v=onepage&q=%22when%20i%22%20iron%20hobbs&f=false |journal=[[Vegetarian Times]] |pages=70–75 |postscript=<!-- Bot inserted parameter. Either remove it; or change its value to "." for the cite to end in a ".", as necessary. -->{{inconsistent citations}}}}

==External links==

* [http://www.ironrichfoods.info/ Iron Rich Foods] Extensive information on Iron Rich Foods

* [http://www.cdc.gov/mmwr/preview/mmwrhtml/00051880.htm Recommendations to Prevent and Control Iron Deficiency in the United States]

* [http://www.irontherapy.org/a.php3?a=ito-textbook--4339 Textbook on iron deficiency in various settings] IronTherapy.Org

* [http://www.irondeficiencyguide.com/ Iron Deficiency conditions, symptoms, treatments] Iron Deficiency Guide

{{Nutritional pathology}}

* [http://irondeficiencyhq.com/ Iron Deficiency Connected To Restless Leg Syndrome, Panic Attacks, and Hair Loss.]

{{Use dmy dates|date=June 2011}}

[[Category:Mineral deficiencies]]

[[Category:Iron metabolism|Deficiency]]

[[Category:Red blood cell disorders]]

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[[el:Σιδηροπενία]]

[[es:Ferropenia]]

[[pt:Deficiência de ferro]]

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