Plant phenolics converted in the intestines to a type of phytoestrogen ("plant" estrogen) with antioxidant properties. As a weak estrogen, lignans may affect hormone-related cancers by tying up the estrogen receptors on cells. Lignans are abundant in flax seed and flour, whole grain products and some berries. Vegetables and other grains are also sources.
Lignans are considered phytoestrogens. They bind to estrogen sites and exhibit a weak estrogenic active and in some cases may block the action of estrogen altogether. Lignan precursors are found in seeds, whole grains, legumes vegetables and berries. Lignan precursors are converted by bacteria in human intestine into the lignans, enterodiol and enterolactone. May play a role in estrogen mediated cancers by reducing the cancer promoting effect of estrogen in cancer cells. Foods high in lignan precursors are associated with lower occurrences of cancer and cardiovascular diseases. It has not been established whether it is the lignans or other nutrients in these products are the protective agents. Evidence leans to a combination effect. A lignan sesamolin found in sesame seeds has be identified as a potent reducer of hypertension. Flaxseed have the highest level of lignan precursors followed by sesame seeds.