American adults need to consume more foods rich in potassium—at least 4,700 milligrams a day to lower blood pressure, blunt the effects of salt, and reduce the risk of kidney stones and bone loss. But most Americans only get half that amount.  A sampling of foods rich in potassium include serving sizes of spinach (840 mg), baked potato with the skin (800), sweet potato (700), white beans (600), yogurt (600), halibut (600), Brussels sprouts (500), orange juice (500), lima beans (475), bananas (470), and broccoli (460).  Potassium supplements are not recommended and could be dangerous unless doctor recommended.

Source: Dietary Reference Intakes: Water, Potassium, Sodium, Chloride, and Sulfate, Institute of Medicine, February 2004.