I can't really give you an answer on that one, but right now I'm increasing my intake of zinc through supplements and broccoli. Supposedly:
Zinc is absolutely necessary to maintain and increase testosterone, and unfortunately many of us are deficient. Zinc also inhibits something called the aromatase enzyme, which converts testosterone to estrogen. All in all, zinc is a very powerful element. It's even better to take ZMA, which is zinc combined with magnesium. You can find ZMA at most health food stores.
I'm not sure if this will work, but right now I'm giving it a try. I'll post my results if my experiment with zinc amounts to anything.