Question: are onion high in potassium?
Answer: Onions are low in sodium, potassium and phosphorus, regardless of the color or variety. One 1/4-inch slice from a large onion contains 2 mg sodium, 55 mg potassium and 11 mg phosphorus. ½ cup chopped, raw onion contains 3 mg sodium, 117 mg potassium and 23 mg phosphorus.