By DR. RICHARD BELIVEAU, QMI Agency
September 20, 2010 2:00am
As many people are aware, female sex hormones called estrogens play an important role in the development of breast cancer. When the levels of these hormones get too high, they can cause an excessive stimulation in the growth of mammary glands and subsequently, an increase in cancer risk. (This is called hormone-dependent breast cancer.)
But some types of plants contain molecules that have a structure similar to estrogen. These molecules are called phytoestrogens. They can have several positive effects on the metabolism of estrogens in humans, including reducing the amount of these hormones in the blood stream and stopping them from binding to the surface of cells in the breast. These combined effects can reduce the negative impact of estrogens and in turn reduce the cancer risk.
LIGNANS – PHYTOESTROGENS WORTH GETTING TO KNOW
Phytoestrogens come in three forms: a) as isoflavones, found only in soybeans, b) as coumestans, found mainly in alfalfa and clover, and c) as lignans, found mainly in fruits and vegetables and some grains. But the two main lignans – secoisolariciresinol and matairesinol – are abundant in flax seeds, which register levels up to 3,000 times higher than other plant products.
And unlike other classes of phytoestrogens, lignans are not absorbed directly but are instead metabolized first by the intestinal bacteria. The by-products of this metabolic process – enterolactone and enterodiol – have less affinity with the body’s estrogen receptors than other phytoestorgens, but have additional anti-cancer properties that could help defend against breast cancer.
This protective effect is supported by a recent analysis of epidemiological studies looking into the impact of lignan molecules on breast cancer risk.