A 2012 study published in "The American Journal of Clinical Nutrition" reported that approximately 98 percent of American adults do not consume enough potassium each day. Eating bananas is commonly touted as a good way to increase your potassium intake, but bananas are not as rich a source of the mineral as many other fresh fruits and vegetables. Talk to your doctor or a nutritionist if you're concerned about getting enough potassium in your diet.
The U.S. Department of Agriculture reports that a medium-sized fresh banana that's between 7 and 7 7/8 inches long contains approximately 422 milligrams of potassium. Adult men and women should have 4,700 milligrams of potassium each day, and one banana fulfills 9 percent of this requirement. According to the Food and Drug Administration's guidelines, bananas cannot be considered a good source of potassium since they do not provide at least 10 percent of the recommended daily allowance of potassium.
Comparison to Other Foods
A banana contains about as much potassium as a 1-cup serving of cooked celery, 1 cup of canned grapefruit sections, 1/2 cup of cooked spinach, 1 ounce of sunflower seeds or 6 fluid ounces of tomato juice. Foods that provide between 10 and 19 percent of an adult's RDA of potassium include 1/2 cup of raisins, 6 fluid ounces of prune juice, 1 cup of cooked beans such as black beans and a medium-sized baked potato. Excellent sources of potassium -- foods with more than 20 percent of the RDA per serving -- include dried apricots, green soybeans, almonds and canned tomato puree.
Your body uses the potassium you obtain from foods like bananas to trigger enzymes that break down carbohydrates and to aid in building strong teeth and bones. Potassium is required to maintain the electrolyte concentration that allows your muscles to contract and your nervous system to transmit impulses. If your diet doesn't contain adequate potassium, you're significantly more likely to die of heart disease, says a 2011 study published in the "Archives of Internal Medicine." You also have an increased risk of osteoporosis, hypertension, stroke and kidney stones.
Heat does not destroy potassium, so whether you eat a banana fresh, sauteed, or mashed and mixed into baked goods such as muffins or cakes, you'll receive approximately the same amount of potassium. For a potassium-rich breakfast, try whole-wheat banana pancakes or waffles with grapefruit or orange juice. Serve roasted bananas mixed with other fruit as a light side dish for grilled fish like yellowtail or swordfish, which both contain over 500 milligrams of potassium per serving. As a snack, pair a banana with a mixture of roasted unsalted nuts and seeds.