The chemical and biological characteristics of fatty acid esters of hydroxyl fatty acids.

This article reviews fatty acid esters of hydroxyl fatty acids (FAHFAs), a class of endogenous bioactive lipids discovered in 2014, focusing on their dietary sources, analytical methods, and biological effects, particularly regarding intestinal health. FAHFAs are found in various animal, plant, and microbial foods, including meats, breast milk, fruits, vegetables, cereals, oils, and fermented teas, though their natural concentrations are generally low. Advanced liquid chromatography–mass spectrometry techniques, often combined with chemical derivatization, have improved the detection and structural characterization of FAHFAs, including their chiral isomers. Biologically, FAHFAs exhibit anti-inflammatory, antidiabetic, and gut-protective properties, influencing intestinal barrier integrity and gut microbiota composition, but most functional studies rely on synthetic standards rather than dietary FAHFAs. The review highlights current challenges such as low dietary FAHFA levels, incomplete understanding of their bioavailability and mechanisms in humans, and the need for more sensitive analytical methods and comprehensive studies on their health impacts and potential in functional food development.