Enterolactone is a mammalian lignan with an estrogen-like diphenolic structure. It is produced by intestinal bacteria from two plant precursors (matairesinol and secoisolariciresinol) obtained in the diet. Enterolactone and other lignans and phytoestrogens have been associated with a reduced risk of acute coronary events, hormone-dependent cancers, and possibly osteoporosis. Several studies have suggested that serum enterolactone may serve as a biomarker of a healthy, high-fiber diet. Cayman's Enterolactone ELISA is a competitive assay that utilizes a standard curve ranging from 15.6-2,500 pg/ml.