Diets high in fiber contain plant lignan species that may be directly responsible for some observed health benefits of these diets.{10196} Enterolactone is an enterobacterial breakdown product of plant lignans that is absorbed and can be measured in human serum. Enterolactone and other ligans and phytoestrogens have been associated with a reduced risk of acute coronary events, hormone-dependent cancers, and possibly osteoporosis. Recent observations have shown an inverse association between serum enterolactone levels and serum isoprostane levels.{10625} This association implies a protective effect against oxidative injury associated with the dietary lignans themselves, enterolactone, or some intermediate in this pathway.