Editing Propionic acid (section)

===Human occurrence===
The human skin is host of several species of ''Propionibacteria''.  The most notable one is the ''[[Cutibacterium acnes]]'' (formerly known as ''Propionibacterium acnes''), which lives mainly in the [[sebaceous gland]]s of the skin and is one of the principal causes of [[acne]].<ref>{{cite journal |doi=10.1016/j.clindermatol.2004.03.005 |title=Acne and propionibacterium acnes |year=2004 |last1=Bojar |first1=Richard A. |last2=Holland |first2=Keith T. |journal=Clinics in Dermatology |volume=22 |issue=5 |pages=375–379 |pmid=15556721 }}</ref> Propionate is observed to be among the most common [[short-chain fatty acid]]s produced in the [[large intestine]] of humans by [[gut microbiome|gut microbiota]] in response to indigestible carbohydrates ([[dietary fiber]]) in the diet.<ref>{{cite journal |last1=Cani |first1=Patrice D. |last2=Knauf |first2=Claude |title=How gut microbes talk to organs: The role of endocrine and nervous routes |journal=Molecular Metabolism |date=27 May 2016 |volume=5 |issue=9 |pages=743–752 |doi=10.1016/j.molmet.2016.05.011 |pmid=27617197 |pmc=5004142 }}</ref><ref name = metab>{{cite journal|last1=den Besten |first1=G |last2=van Eunen |first2=K |last3=Groen |first3=AK |last4=Venema |first4=K|last5=Reijngoud|first5=DJ|last6=Bakker|first6=BM|title=The role of short-chain fatty acids in the interplay between diet, gut microbiota, and host energy metabolism.|journal=Journal of Lipid Research|date=September 2013|volume=54|issue=9|pages=2325–40|doi=10.1194/jlr.R036012 |doi-access=free |pmid=23821742|pmc=3735932}}</ref> The role of the gut microbiota and their metabolites, including propionate, in mediating brain function has been reviewed.<ref>{{cite journal |doi=10.1038/mp.2016.50 |doi-access=free |title=From gut dysbiosis to altered brain function and mental illness: Mechanisms and pathways |year=2016 |last1=Rogers |first1=G. B. |last2=Keating |first2=D. J. |last3=Young |first3=R. L. |last4=Wong |first4=M-L |last5=Licinio |first5=J. |last6=Wesselingh |first6=S. |journal=Molecular Psychiatry |volume=21 |issue=6 |pages=738–748 |pmid=27090305 |pmc=4879184 |s2cid=18589882 }}</ref>

A study in mice suggests that propionate is produced by the bacteria of the genus ''[[Bacteroides]]'' in the gut, and that it offers some protection against ''[[Salmonella]]'' there.<ref>{{cite journal |doi=10.1016/j.chom.2018.07.002   |title=A Gut Commensal-Produced Metabolite Mediates Colonization Resistance to Salmonella Infection |year=2018 |last1=Jacobson |first1=Amanda |last2=Lam |first2=Lilian |last3=Rajendram |first3=Manohary |last4=Tamburini |first4=Fiona |last5=Honeycutt |first5=Jared |last6=Pham |first6=Trung |last7=Van Treuren |first7=Will |last8=Pruss |first8=Kali |last9=Stabler |first9=Stephen Russell |last10=Lugo |first10=Kyler |last11=Bouley |first11=Donna M. |last12=Vilches-Moure |first12=Jose G. |last13=Smith |first13=Mark |last14=Sonnenburg |first14=Justin L. |last15=Bhatt |first15=Ami S. |last16=Huang |first16=Kerwyn Casey |last17=Monack |first17=Denise |journal=Cell Host & Microbe |volume=24 |issue=2 |pages=296–307.e7 |pmid=30057174 |pmc=6223613 }}</ref> Another study finds that fatty acid propionate can calm the immune cells that drive up blood pressure, thereby protecting the body from damaging effects of high blood pressure.<ref>{{cite journal |doi=10.1161/CIRCULATIONAHA.118.036652 |title=Short-Chain Fatty Acid Propionate Protects from Hypertensive Cardiovascular Damage |year=2019 |last1=Bartolomaeus |first1=Hendrik |last2=Balogh |first2=András |last3=Yakoub |first3=Mina |last4=Homann |first4=Susanne |last5=Markó |first5=Lajos |last6=Höges |first6=Sascha |last7=Tsvetkov |first7=Dmitry |last8=Krannich |first8=Alexander |last9=Wundersitz |first9=Sebastian |last10=Avery |first10=Ellen G. |last11=Haase |first11=Nadine |last12=Kräker |first12=Kristin |last13=Hering |first13=Lydia |last14=Maase |first14=Martina |last15=Kusche-Vihrog |first15=Kristina |last16=Grandoch |first16=Maria |last17=Fielitz |first17=Jens |last18=Kempa |first18=Stefan |last19=Gollasch |first19=Maik |last20=Zhumadilov |first20=Zhaxybay |last21=Kozhakhmetov |first21=Samat |last22=Kushugulova |first22=Almagul |last23=Eckardt |first23=Kai-Uwe |last24=Dechend |first24=Ralf |last25=Rump |first25=Lars Christian |last26=Forslund |first26=Sofia K. |last27=Müller |first27=Dominik N. |last28=Stegbauer |first28=Johannes |last29=Wilck |first29=Nicola |journal=Circulation |volume=139 |issue=11 |pages=1407–1421 |pmid=30586752 |pmc=6416008 }}</ref>