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.