Judging by comments on various topics, it seems that most Paleo folks eat a good amount of eggs. I certainly eat a lot more eggs than I used to since going (mostly...) Paleo.
Since most chickens - even pastured chickens- eat feed that contains soy, should we be concerned about soy phytoestrogens that pass from the chicken to the egg? Is there an upper limit on the number of eggs we should consume in a day?
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OK, I found this study:
According to this, eggs do contain some phytoestrogens. Pastured eggs have less than caged, but the difference is not that much. All types of eggs had less than most cheeses listed.
The amounts in all the animal foods listed are dwarfed by soy foods to the point it seems silly to worry about, however I would still love to know if anyone else has thoughts on this. Especially dosage - could even relatively small amounts of phytoestrogens be a problem?
Unless the soy's been fermented for a good year or so (good luck), I suspect it's bad for chickens and their eggs alike. Don't have any hard proof of that on hand, though. My guess is most organic producers that are large enough to sell to grocery stores probably depend on a fair amount of soy-containing (or contaminated) feed. If you eat a lot of eggs, I'd recommend getting them from the farmer's market, where you're likelier to find a small supplier whose chickens are soy-free (there's at least three at my neighborhood market, for instance; you just have to ask).