The old wives' tale of xenoestrogen/phytoestrogen/isoflavone activity is right up there with your toenails, and seawater, containing gold (and uranium): an extremely tiny nugget of truth wrapped around a vast sea of irrational passion. It's pop-science at it's worst, but it's also such an interesting and colorful little myth that it's discussed often on internet forums and written up in women's magazines.
I don't have numbers handy, but I've seen people run this sort of calculation before. In short, these substances are present in food in extremely small quantities, such that, if they had a direct injection effect, you might see an effect if you ate several pounds of tofu each day. Since the tofu is absorbed through your digestive tract and much of that material is broken down in the process, the quantity required becomes several dozen pounds per diem, assuming still that the substances are equal in activity level. Since the biological activity level (it's effect on estrogen-receptors and associated metabolic pathways) is usually on the order of a hundredth to a ten-thousandth of normal, you'd then have to eat several tons of tofu, or similar foods, per diem, for many months on end, to see an effect similar to a low dose of estrogen.
Unless you scarf more than ten tofurkeys per day, I wouldn't worry. If you are pre-HRT, your body produces a vastly greater hormone load, and the increase is noise. If you are post-HRT, your injections contain a vastly greater hormone load, and the increase is noise.
If you need to know more, ask your endocrinologist, visit your local university librarian, or poke around
Snopes.com and other such sites.
P.S.: A slightly more interesting topic is the presence of more toxic byproducts in tobacco which may inhibit androgens, not to mention the radiation load from tobacco smoke inhalation.
- N
