The recommended potassium intake for adults is 4,700 milligrams a day. Fruits and vegetables provide the most significant sources of potassium, particularly potatoes, squash, green leafy vegetables, legumes, bananas, citrus and dried fruits.Whole-grain breads and cereals, meats, milk, nuts and seeds are also rich in potassium.otassium is a mineral and electrolyte that plays a significant role in metabolism, water, and chemical balance in the body.