What are bile acids?

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Bile acids are molecules synthesized from cholesterol in the liver that play a critical role in the digestion and absorption of dietary fat and fat-soluble vitamins (e.g., vitamin A).[1][2] Bile acids also act as signaling molecules that regulate the expression of genes involved in energy metabolism and immune responses,[1][2] and they can be metabolized by gut bacteria, which influences microbial composition and intestinal barrier function.[1][2]

Some bile acids are used to treat certain conditions.[3] For example, ursodeoxycholic acid (UDCA) — a component of TUDCA (taurine + UDCA) — may be of use in the treatment of cholestasis,[4][5] metabolic-associated fatty liver disease (MAFLD, formerly called nonalcoholic fatty liver disease, NAFLD),[6][7] primary biliary cholangitis,[8][9] and gallstones.[10] However, further randomized controlled trials are needed to fully understand the efficacy of UDCA in these conditions.

References
1.^di Gregorio MC, Cautela J, Galantini LPhysiology and Physical Chemistry of Bile Acids.Int J Mol Sci.(2021 Feb 10)
2.^Molinaro A, Wahlström A, Marschall HURole of Bile Acids in Metabolic Control.Trends Endocrinol Metab.(2018 Jan)
3.^Thomas C, Pellicciari R, Pruzanski M, Auwerx J, Schoonjans KTargeting bile-acid signalling for metabolic diseases.Nat Rev Drug Discov.(2008 Aug)
4.^Huang L, Li S, Chen J, Zhu Y, Lan K, Zeng L, Jiang X, Zhang LEfficacy and safety of ursodeoxycholic acid in children with cholestasis: A systematic review and meta-analysis.PLoS One.(2023)
5.^Ovadia C, Sajous J, Seed PT, Patel K, Williamson NJ, Attilakos G, Azzaroli F, Bacq Y, Batsry L, Broom K, Brun-Furrer R, Bull L, Chambers J, Cui Y, Ding M, Dixon PH, Estiú MC, Gardiner FW, Geenes V, Grymowicz M, Günaydin B, Hague WM, Haslinger C, Hu Y, Indraccolo U, Juusela A, Kane SC, Kebapcilar A, Kebapcilar L, Kohari K, Kondrackienė J, Koster MPH, Lee RH, Liu X, Locatelli A, Macias RIR, Madazli R, Majewska A, Maksym K, Marathe JA, Morton A, Oudijk MA, Öztekin D, Peek MJ, Shennan AH, Tribe RM, Tripodi V, Türk Özterlemez N, Vasavan T, Wong LFA, Yinon Y, Zhang Q, Zloto K, Marschall HU, Thornton J, Chappell LC, Williamson CUrsodeoxycholic acid in intrahepatic cholestasis of pregnancy: a systematic review and individual participant data meta-analysis.Lancet Gastroenterol Hepatol.(2021 Jul)
6.^Orlando R, Azzalini L, Orando S, Lirussi FBile acids for non-alcoholic fatty liver disease and/or steatohepatitis.Cochrane Database Syst Rev.(2007 Jan 24)
7.^Patel VS, Mahmood SF, Bhatt KH, Khemkar RM, Jariwala DR, Harris B, George MM, Kurudamannil RA, Anyagwa OE, Tak RS, Kassem MUrsodeoxycholic Acid's Effectiveness in the Management of Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis.Euroasian J Hepatogastroenterol.(2024 Jan-Jun)
8.^Jakub Gazda, Sylvia Drazilova, Matej Gazda, Martin Janicko, Tomas Koky, Marian Macej, Marco Carbone, Peter JarcuskaTreatment response to ursodeoxycholic acid in primary biliary cholangitis: A systematic review and meta-analysisDig Liver Dis.(2023 Oct)
9.^Poropat G, Giljaca V, Stimac D, Gluud CBile acids for primary sclerosing cholangitis.Cochrane Database Syst Rev.(2011 Jan 19)