Foot odor: Difference between revisions

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{{Short description|Type of body odor that affects the feet of humans}}

'''Foot odor''' often results from wearing [[shoe]]s and/or [[sock]]s for many hours, as they provide warm, moist conditions for [[bacterium|bacteria]] and/or [[fungi]] to thrive.

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'''Foot odor''' (also spelled '''foot odour''') or '''bromodosis''' is a type of [[body odor]] that affects the [[foot|feet]] of [[human]]s.

Usually people grow up believing foot odor is unpleasant, making people embarrassed about how their feet smell. Kids often grow up making fun of the fact that their feet smell ("Trick or Treat, smell my feet..."), etc. For this reason, in Western countries, where shoes are worn for most of the day, some people avoid removing their shoes around others, or they are asked to keep them on or put them back on. This is paradoxical, since being shoeless as much as possible is one of the best ways to prevent the feet from becoming smelly in the first place. Note that there is no "foot odor" stigma in countries where shoes are removed upon entering the home(for a more detailed discussion of this topic, see [[Shoes]]).

==Causes==

The smell of feet is usually a warm, sweet scent, even floral, but can sometimes be more musty (girls' feet are usually sweeter, while boys' are more pungent). Brevibacteria are considered a major cause of foot odor, as they ingest dead skin on the feet, especially on the soles and between the toes, converting in the process the amino acid methionine to methane thiol, which has a sulfuric aroma. Brevibacteria also give cheeses such as Limburger, Bel Paese, Port du Salut, and Muenster their characteristic pungency.[http://www.wheatoncollege.edu/Quarterly/q2003fall/bacteria.html]

The main cause is foot [[Perspiration|sweat]] (also see [[focal hyperhidrosis]]). Sweat itself is odorless; however, it creates a beneficial environment for certain bacteria to grow, producing odorous substances. These bacteria are naturally present on our skin as part of the [[human microbiome]]. The front part of the foot produces the most sweat.<ref>{{cite web|url=http://www.ijisr.com/sites/default/files/issues-pdf/034.pdf|title=INTERACTION OF SILVER NITRATE WITH COMMERCIALLY AVAILABLE COTTON SOCKS; RELATIONSHIP TO THE ANTIBACTERIAL ACTION OF SILVER IONS|date=21 February 2015|access-date=31 March 2015|archive-date=August 27, 2019|archive-url=https://web.archive.org/web/20190827012526/http://www.ijisr.com/sites/default/files/issues-pdf/034.pdf|url-status=dead}}</ref>

The smell is exacerbated by factors that increase sweating, such as wearing closed-toe shoes. Sports footwear such as [[sneakers]] is often heavily padded inside which provides a perfect environment to trap moisture and allow the bacteria to thrive. Socks can trap [[foot hair]], especially on the [[toe]]s, and may contribute to odor intensity by increasing [[surface area]] on which bacteria can thrive.{{cn|date=July 2017}}

Among the earliest foot deodorants were aromatic herbs such as [[allspice]], which nineteenth-century Russian soldiers would put in their boots. [http://www.foodreference.com/html/fallspice.html]

Some types of powders and [[activated charcoal]] insoles, such as [[Odor Eaters]], have been developed to combat foot odor, but they are not as effective as thoroughly washing feet, choosing shoes with proper [[ventilation]], changing socks regularly, and only wearing shoes when necessary.

Given that [[sock]]s directly contact the feet, their composition can affect foot odor. [[synthetic fiber|Synthetic materials]] like [[polyester]] and [[nylon]] afford less [[breathability|ventilation]] to the foot than do [[cotton]] or [[wool]], leading to increased perspiration and odor, although they can also reduce incidence of [[blister]]s by [[Capillary action|wicking]] away perspiration. Many synthetic socks are treated with chemicals to help reduce odor.<ref>{{Cite web|title=Smelly foot (Foot Odor) - Information from ePodiatry|url=http://www.epodiatry.com/smelly-foot.htm|access-date=2023-01-02|website=www.epodiatry.com}}</ref>

Since many martial arts are practiced [[barefoot]], odor can pose a problem(in countries with a high incidence of foot odor).

Wearing closed-toe shoes (e.g., [[ballet flat]]s or pumps) without socks leads to accumulation of sweat, dead [[keratinocytes|skin cells]], dirt, and [[sebaceous gland|oils]], further contributing to bacterial growth.

Although most people believe the scent of feet unpleasant (usually more often than not because of a societal bias more than actual experience), some people find smelling feet [[sexually arousing]]. This can be part of a [[foot fetish]]. Some people also have fetishes for the sock or shoe scent that usually accompanies warm feet (for example as part of a [[shoe fetish]]), or enjoy [[foot worship]]. Girls' feet often smell sweet and fruity, almost like honey. Many people find this scent attractive. (See also: [[mysophilia]]).

==Odor See also qualities==

''[[Brevibacteria]]'' are considered a major cause of foot odor because they ingest dead skin on the feet and, in the process, convert the [[amino acid]] [[methionine]] into [[methanethiol]], a colorless gas with a distinctive [[sulfur]]ic aroma. The dead skin that fuels this process is especially common on the [[Sole (foot)|sole]] and [[interdigital webbing|between the toes]]. Brevibacteria also give such [[cheese]]s as [[Limburger]], [[Bel Paese (cheese)|Bel Paese]], [[Port Salut]], [[Pálpusztai]] and [[Munster (cheese)|Munster]] their characteristic [[pungency]].<ref>{{Cite journal

* [[Body odor]]

| title= Characterization of aerobic non-lipophilic coryneforms from human feet

| vauthors = Anthony RM, Noble WC, Pitcher DG | journal= Clinical and Experimental Dermatology | issn = 0307-6938

| year = 1992

| volume= 17 | number=2

| pages = 102–105 |publisher=Blackwell Scientific Publications

| doi = 10.1111/j.1365-2230.1992.tb00174.x | pmid=1516232

| s2cid = 33517719 }}</ref>{{rp|103}}

[[Isovaleric acid]] (3-methyl butanoic acid), another source of foot odor, is produced by ''[[Staphylococcus epidermidis]]'', a bacterial species normally [[skin flora|resident on human skin]]<ref>{{Cite journal| doi = 10.1139/w05-130| issn = 0008-4166| volume = 52| issue = 4| pages = 357–364| last = Ara| first = Katsutoshi|author2=Masakatsu Hama |author3=Syunichi Akiba |author4=Kenzo Koike |author5=Koichi Okisaka |author6=Toyoki Hagura |author7=Tetsuro Kamiya |author8=Fusao Tomita | title = Foot odor due to microbial metabolism and its control| journal = Canadian Journal of Microbiology| date = April 2006| pmid=16699586| citeseerx = 10.1.1.1013.4047}}</ref> and present in several strong-smelling varieties of cheese.<ref>{{cite journal

== External Links ==

| title=Isovaleric acid is mainly produced by Propionibacterium freudenreichii in Swiss cheese

*[http://science.howstuffworks.com/question514.htm HowStuffWorks.com "Why Do Feet Stink?" ]

| author1= Thierry, Anne

| author2=Richoux, Romain

| author3= Kerjean, Jean-René

| journal=International Dairy Journal

| year=2004

| volume= 14 | issue= 9

| pages=801–807

| doi=10.1016/j.idairyj.2004.02.002

| s2cid= 85336899

| url= https://hal.archives-ouvertes.fr/hal-02264923/file/Thierry04_IDJ-iC5_1.pdf

}}</ref>

Other implicated [[microorganisms]] include [[Micrococcaceae]], ''[[Corynebacterium]]'' and ''[[Pityrosporum]]''.<ref>{{Cite journal | title=Body malodours and their topical treatment agents | last=Kanlayavattanakul | first=M |author2=Lourith N | journal=International Journal of Cosmetic Science | volume=33 | issue=4 | pages=298–311|date=August 2011 | pmid=21401651 | doi=10.1111/j.1468-2494.2011.00649.x | doi-access=free }}</ref>

[[Bart Knols]] of [[Wageningen Agricultural University]] in the [[Netherlands]] received a 2006 "[[Ig Nobel Prize]]"<ref>{{cite web |url=https://improbable.com/ig/winners/?amp=1#ig2006 |title=The 2006 Ig Nobel Prize Winners

| series = Past Ig Winners

|website= improbable.com|date=August 2006

}}</ref> for demonstrating that the female ''[[Anopheles gambiae]]'' [[mosquito]], known for transmitting [[malaria]], is "attracted equally to the smell of [[Limburger]] cheese and to the smell of human feet".<ref>{{citation |title=On Human Odour, Malaria Mosquitoes, and Limburger Cheese |author= Bart G.J. Knols |journal= The Lancet |volume= 348 |issue= 9037 |date= November 9, 1996 |page=1322|doi=10.1016/S0140-6736(05)65812-6 |pmid=8909415|s2cid= 12571262 }}</ref> [[Fredros Okumu]], of the [[Ifakara Health Institute]] in [[Tanzania]], received grants in 2009 and 2011 to develop [[mosquito control|mosquito attractant]]s and [[insect trap|trap]]s to combat malaria.<ref>{{cite news |url=http://www.huffingtonpost.com/2011/07/13/stinky-socks-smell-malaria_n_896819.html |title= Scientists: Stinky Sock Smell Helps Fight Malaria |orig-year=July 13, 2011 |date=July 15, 2011 | work=Huffington Post |first=Michael |last=McLaughlin}}</ref> He used a blend of eight chemicals four times more effective than actual human secretions.<ref>{{cite news |language = en |author = Susannah Palk |url = http://edition.cnn.com/2011/WORLD/africa/07/26/tanzania.malaria.socks/index.html |archive-url = https://web.archive.org/web/20110726223123/http://edition.cnn.com/2011/WORLD/africa/07/26/tanzania.malaria.socks/index.html |url-status = dead |archive-date = July 26, 2011 |title = 'Dirty sock smell' lures mosquitoes to a sticky end |publisher = CNN |date = 2 August 2011 |access-date = 14 October 2018}}</ref>

==Prevention==

Maintaining good foot hygiene is the best way to prevent foot odour as it eliminates odour causing bacteria and removes dead skin cells as well as [[sebum]]. A foot file, [[pumice stone]] or chemical treatment, such as an [[Alpha hydroxy acid]] containing foot peel preparation, can be used to remove dead skin cells.<ref>{{Cite web|title = The solution - Stinkyfeet|url = http://www.stinkyfeet.org/the-solution/|website = Stinkyfeet|access-date = 2016-02-12|language = en-US|archive-date = May 14, 2021|archive-url = https://web.archive.org/web/20210514110237/http://www.stinkyfeet.org/the-solution/|url-status = dead}}</ref><ref>{{cite web |last1=VELASCO |first1=PIA |title=Read This Before You Try the 'Baby Foot' Peel Craze |url=https://www.goodhousekeeping.com/beauty-products/a38129/baby-foot-peel-safety/ |website=Good Housekeeping |access-date=19 October 2019|date=2019-03-25 }}</ref>

Using antibacterial soap to wash feet daily; keeping feet dry by changing socks daily and wearing cotton or wool instead of synthetic fibres can also help reduce moisture build-up.

Using medicated insoles and foot powder can also help.<ref>{{cite web |title=How to stop smelly feet |url=https://www.nhs.uk/live-well/healthy-body/how-to-avoid-smelly-feet/ |website=NHS UK |publisher=National Health Service |access-date=19 October 2019|date=2018-04-26 }}</ref>

==Management==

In some cases, medical intervention may be needed to treat the bacterial or fungal infection with a topical antibacterial or fungicide.<ref>{{cite journal |last1=Fernández-Crehuet |first1=P |last2=Ruiz-Villaverde |first2=R |title=Pitted keratolysis: an infective cause of foot odour. |journal=Canadian Medical Association Journal |date=21 April 2015 |volume=187 |issue=7 |pages=519 |doi=10.1503/cmaj.140809 |pmid=25712956 |pmc=4401600 }}</ref><ref>{{cite web |title=ATHLETE'S FOOT (TINEA PEDIS) |url=https://www.summitmedicalgroup.com/library/pediatric_health/hhg_athlete_foot/ |website=Summit Medical Group |access-date=19 October 2019}}</ref>

==As a paraphilia==

Foot odor is one of the most widespread forms of olfactophilia;<ref>{{cite web|url=http://podiatry.curtin.edu.au/fetish.html#freud|archive-url=https://web.archive.org/web/20071018035445/http://podiatry.curtin.edu.au/fetish.html#freud|url-status=dead|archive-date=18 October 2007|title=The History of Footwear - Foot Fetish and Shoe Retifism|access-date=28 May 2018}}</ref> in a 1994 study, 45% of those with a [[foot fetish]] were found to be aroused by [[smelly socks]] and/or feet, but most importantly by the intensity of the smell produced by such bacteria.<ref>{{citation |title=Comprehensive handbook of psychopathology |author1=Patricia B. Sutker |author2=Henry E. Adams |url=https://books.google.com/books?id=uEx84FQPYoAC|page=762 |year=2001 |publisher=Springer |isbn=978-0-306-46490-4}}</ref>

==See also==

* [[Body odor]]

* [[Body odour and sexual attraction]]

* [[Shoe]]

* [[Smelly socks]]

==References==

{{Reflist|2}}

{{DEFAULTSORT:Foot Odor}}

[[Category:Foot]]

[[Category:Hygiene]]

[[Category:Body odor]]