Honestly, even soy shouldn't be bad... Unless you're eating absolutely ridiculous amounts of anything phytoestrogenic, none of it should come close to enough saturation to compete with PM.
PM is extremely competitive for estrogen receptors compared to most other estrogens.
It is also an extremely powerful estrogen.
These things are due to how similar to estradiol it's major constituents are. Curiously, though there's been no scientific study to back this up, deoxymiroestrol actually appears to bind more readily than even human estradiol does.
Now... all that being said... I would definitely discourage mixing any other phytoestrogen SUPPLEMENTS with PM. You could reach enough saturation doing that to interfere with the PM.
The ONLY thing that I could see mixing with PM and expect an estrogenic bonus instead of deficit would be BO. But by and large, most women will not need to mix PM with anything else to get excellent results.
They also shouldn't have to avoid any foods they like for fear of interfering with the PM either. There ARE foods you could ADD to your diet to improve uptake, but that's about it really. Unless you're already eating them anyways.
