Abstract
Secondary bile acids (BAs) and short chain fatty acids (SCFAs), two major types of bacterial metabolites in the colon, cause opposing effects on colonic inflammation at chronically high physiological levels. Primary BAs play critical roles in cholesterol metabolism, lipid digestion, and host–microbe interaction. Although BAs are reabsorbed via enterohepatic circulation, primary BAs serve as substrates for bacterial biotransformation to secondary BAs in the colon. High-fat diets increase secondary BAs, such as deoxycholic acid (DCA) and lithocholic acid (LCA), which are risk factors for colonic inflammation and cancer. In contrast, increased dietary fiber intake is associated with anti-inflammatory and anticancer effects. These effects may be due to the increased production of the SCFAs acetate, propionate, and butyrate during dietary fiber fermentation in the colon. Elucidation of the molecular events by which secondary BAs and SCFAs regulate colonic cell proliferation and inflammation will lead to a better understanding of the anticancer potential of dietary fiber in the context of high-fat diet-related colon cancer. This article reviews the current knowledge concerning the effects of secondary BAs and SCFAs on the proliferation of colon epithelial cells, inflammation, cancer, and the associated microbiome.
Highlights
Colon cancer accounts for approximately 135,000 new cancer cases in the United States each year [1,2,3]
Research has shown that differences in the compositional nature of gut microbiome are associated with differences in risk of obesity and colon cancer via chronic inflammation [13]
Epidemiologic studies have shown that subjects who consume a high-fat diet produce elevated levels of fecal secondary bile acids (BAs), mainly deoxycholic acid (DCA) and lithocholic acid (LCA), as do colon cancer patients [132,133]
Summary
Colon cancer accounts for approximately 135,000 new cancer cases in the United States each year [1,2,3]. A “Western” diet that is high in fat (SFAs) and low in fiber promotes colonic inflammation and cancer [6,7]. A growing body of evidence demonstrates that increased dietary fiber intake is associated with many beneficial effects including amelioration of obesity and anti-inflammatory and anticancer activities in the colon [10,14]. These effects might be due to the increased production of short-chain fatty acids. TThheehhuummaannggaasstrtrooinintetesstitninaal l(G(GI)I)trtarcatctrerperperseesnetnstasnanabaubnudnadnatnrtesreersveorvirooirf omfimcriocbroesbewsiwthitohveorv1e0r010tr0iltlrioilnliobnacbtaecritaergiarogurpoeudpienduinp utop1t0o0100s0p0escpieesci[e1s8,[1198],.1B9]a.cBtearcitaelrdiaivl derisvietyrsiintythine tghuetgisutreilsarteivlaetliyvleolyw,loaws c, oams cpoamrepdatroedmtiocrmobiciarol bcoiaml cmoumnmitiuensi(t>ie5s0(>b5a0ctbearicatleprihayl lpah)yfolau)nfdouinndwiantewr aatnedr asnoidl esnoivlieronnvmiroenntms e[7n]t.sT[h7]e. bTahcetebraiacltecroinasl tciotunesntittsuoefnhtsuomfahnugmuatnmgiucrtombiioctraobarioetdaoamreindaotmedinbaytetwd obymtawjoor mphayjolar, Bpahcytelaro, idBeatecstearnoiddeFteirsmaicnudtesF; iwrmhiecruetaess;thwe hpehryelaas Ptrhoteeobpahcytelraia,PVroerteroubcaocmteircirao,biaV,eArrcutcinomobiaccrotebriiaa,, AFuctsionboabcatcetreirai,a,anFdusCobyaacntoerbiaac,tearniadaCreyapnroebsaecntetriina marienoprrepsreonptoirntiomnisn[o7r,2p0r].opPorretvioanlesn[t7g,2e0n]e. rParienvcalluednet gBeancteerraoideisn, cEluubdaecteriBuamct,eBroifiiddeosb,acteEruiubmac,tReruiummin, ocoBccifuids,obPaecptteorsiturmep,tocoRcucumsi,nPorcoopcicounsi,bactPeerpiutoms,trCeplotsotcroidcciuums,, PLraocptoiboanciiblaluctse, rEiuscmh,ericChlioa,stSrtirdeiputmoc,occLuasc,taonbadcailrluchs,aeaEl sgcehneruischMiae,thaSntorbepretvoicboaccctuers,[7,a2n0,d21].aTrchheameailcrogbeionmuse Mcoenthtrainboubtreesvtiboahctoemr [e7o,2st0a,2ti1c].reTghuelamtiiocnroibniommaenycotinstsruibeus tiensotuorhboomdey,oastnadticthreeginutleartrieolnatiinonmshainpyotfishsousetss iannodutrhbeoirdmy,icarnodbitohteaiinstearmreulattuioanlisshtiicpsoyfmhboisotssias,nwd hthicehirrmefiecrrsotboioatahiesaalthmyubtualaalniscteicosfymmibciroosbise,swinhitchhe rgeufet r[s22to,2a3]h. eHaoltwhyevbearl,aonncceeotfhmisimcruobtueasliinsttichesygmutb[io22si,s23is].dHisorwupevteedr,, iotnmceaythliesamd utotutahleisdtiecvseylompbmioesnist oisf dchisrrounpicteddi,sietamseasyinlcelaudditnogthcoeldoneviceilnopflmamenmtaotifocnharonndiccadnicseeras[2es4]i.ncluding colonic inflammation and cancer [24]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
