foods that are rich in magnesium potassium and calcium
1 Brazil nuts contain high levels of minerals such as selenium, magnesium, copper, manganese, potassium, calcium, iron, phosphorus, and zinc. 2  Magnesium is a key nutrient in a whole host of biological processes. Dark, leafy greens are rich sources of minerals, but spinach in particular contains an abundance of magnesium, calcium, potassium, manganese, and zinc.