If you have kidney disease or are on dialysis, your doctor may require you to follow a low-potassium diet to prevent side effects such as an irregular heartbeat or a heart attack. Some potassium is essential for maintaining your heartbeat, muscle contractions and blood pressure. But when your kidneys aren't able to properly filter potassium, it can build up to dangerously high levels in your body. Your doctor or registered dietitian will instruct you on how much potassium is safe for you to eat daily based on your blood work. In general, low-potassium foods contain less than 200 milligrams of the mineral per serving.
You can still eat a variety of fruits on a low-potassium diet. Apples, blueberries, blackberries, cherries, grapes, peaches, pears, pineapple, plums, raspberries, strawberries and watermelon all provide less than 150 milligrams of potassium per half cup. You can have juices made from these fruits as well, but limit your serving to 1/2 cup. Fruits that contain high levels of potassium and should be avoided include bananas, apricots, cantaloupe, honeydew, kiwi, grapefruit, mangoes, nectarines, oranges, prunes and raisins.
You can safely eat certain vegetables on a low-potassium diet, while others should be avoided. Many of the nonstarchy vegetables, including asparagus, cabbage, carrots, cauliflower, celery, cucumbers, eggplant, lettuce, mushrooms, onions, peppers, summer squash, radishes and turnips, are low in potassium. Avoid winter squash, potatoes, yams and tomatoes, some of the vegetables richest in potassium. The National Kidney Foundation notes that you can leach some of the potassium out of these vegetables by peeling them and soaking them in warm water for at least two hours.
Safe Whole-Grain Foods
Most whole-grain foods do not provide large amounts of potassium. You can eat a 1/2-cup serving of cooked rice, barley, couscous, millet or oatmeal and get less than 70 milligrams of potassium. Baked goods, such as bread, bagels and muffins, are low in potassium as well. It's safe to eat pasta and noodles made from whole grains while limiting potassium intake. However, you should avoid granola and bran cereals, which may contain over 300 milligrams of potassium per 1/3-cup serving.
Allowed Protein-Rich Foods
Animal products and proteins typically provide significant amounts of potassium, but proteins are an essential part of a healthy diet. You'll need to choose protein sources wisely and limit your intake based on the total potassium your dietitian recommends per day. Beef, pork, turkey, chicken, eggs or fish typically provide less than 100 milligrams of potassium per ounce cooked, according to Huntsman Cancer Hospital. Cheddar, bleu, colby, goat, Gouda, mozzarella, provolone and Swiss cheeses are low in potassium providing 50 milligrams or less per ounce. Avoid dried beans, tofu, soy milk, nuts, seeds, yogurt and milk, as these are high in potassium.