Brazil nuts are the best food for selenium I think. One brazil nut can contain 68–91 mcg (different numbers by different sources, etc.) of selenium. Google “brazil nut selenium”. read more
Foods high in selenium include Brazil nuts, oysters, tuna fish, whole wheat bread, sunflower seeds, pork, beef, chicken, crimini mushrooms, and whole grains. It is important to note that the amount of selenium in any product varies greatly by the amount of selenium in the soil in which it was produced/grown/raised. read more