Lignans are phytoestrogens, or plant estrogens. Their precursors are found in a wide variety of plant-based foods and are converted to the lignans, enterodiol and enterolactone, by bacteria in the intestine.

Research suggests these compounds may help protect against hormone-dependent cancers and heart disease.

Because flaxseed is the richest source of lignans, researchers believe it is the synergy of phytonutrients (including lignans) and omega-3's to credit for their beneficial health effects.

References

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