Thread by @ck_eternity_

The most potent phytoestrogen, coumestrol, found primarily in alfalfa and red clover, is one of the few phytoestrogens that actually has any ability to cause endocrine disruption (at least in rodent studies)

Surprisingly, it does this through its anti-estrogenic effects!

All phytoestrogens activate estrogen receptors far weaker than estrogen itself does, because of this they reduce estrogen receptor activation rather than increase it

In some cases this could be beneficial (ie in reducing breast cancer), but issues can still occur

The most potent phytoestrogens still bind to estrogen receptors as strogly as estrogen itself, without properly activating the receptors

This blocks the activity of estrogen, altering gene expression, and preventing feedback loops that regulate estrogen levels

This is what could actually lead to the effects that people blame on increased estrogen, like disruptions in puberty, early ovulation, and issues with sex drive

While the research on these effects are all in rodent studies, in very high doses they may apply to humans as well

This anti-estrogenic effect is only potent enough to cause issues in a handful of herbs/foods, and even then high doses are usually required

The most potent of these compounds are found in alfalfa, red clover, licorice root, and very concentrated forms of soy

Other phytoestrogens are not potent enough to be harmful, unless you're consuming them in massive doses

Other phytoestrogens may even protect against issues like estrogen excess and breast cancer by reducing estrogen receptor activation and increasing estrogen waste metabolism

Neurobehavioral actions of coumestrol and related isoflavonoids in rodents
sciencedirect.com/science/articl…