http://www.drweil.com/drw/u/ART02914/How-to-Boost-Green-Tea-Benefits.html

From the page: “The study found that lemon juice caused a roughly four-fold boost in the recovered levels of catechins; in order, the next most effective juice additions were orange, lime and grapefruit. And one should not be stingy with the juice – while adding 10 percent juice was helpful, the best catechin preservation happened at levels of 20 to 50 percent juice. This suggests that while adding a squeeze of lemon to tea is an excellent idea, it also makes sense to think in terms of 20 to 50 percent blends using orange and grapefruit juices. “