A recent Purdue University study investigating the bioaccessibility of mercury in fish suggests that consumption of various foods containing phytochemicals, such as green and black tea extracts and soy protein, and fiber, such as wheat or oat bran, at the same time as fish that contains mercury might potentially reduce mercury absorption vs. eating fish alone.
Source: “Impact of phytochemical-rich foods on bioaccessibility of mercury from fish,” Soon-Mi Shima, Mario G. Ferruzzib, Young-Cheul Kimc, Elsa M. Janlea and Charles R. Santerrea, Purdue University, Food Chemistry, Vol. 112, Issue 1, Jan. 2009, pp 46-50.doi:10.1016/j.foodchem.2008.05.030