Information on the silicon content of foods and diets is summarized from published literature, and the silicon content of US diets is calculated based on the Food and Drug Administration's Total Diet Study model and literature values for silicon in foods. Silicon levels tend to be higher in foods derived from plants than in foods from animal sources. Foods highest in silicon include grains, especially oats, barley and some rice fractions. Average daily intakes of silicon probably range from about 20 to 50 mg/day with the lower values for animal-based diets and the higher values for plant-based diets. The silicon content of adult US diets, based on the Total Diet Study model, is 19 mg/day for women and 40 mg/day for men.