The kidneys normally maintain fluid and electrolyte levels by excreting excess amounts of these substances in the urine. The kidneys also clean the blood by removing waste products. When kidney function declines, the kidneys do not perform these functions as they should. Special diets for people with kidney disease reduce the risk of kidney failure or other complications.
Low-Sodium Diet
In patients with kidney disease or other kidney disorders, the kidneys cannot maintain normal levels of electrolytes in the blood. This allows the amount of sodium in the blood to increase, causing water retention and swelling of the lower extremities. The water retention caused by excess sodium also causes high blood pressure, as the extra fluid increases blood volume and forces the heart to pump harder, according to MayoClinic.com. A low-sodium diet restricts the consumption of foods that contain high levels of sodium. Restricted foods include salted crackers, frozen entrees, salted potato chips, canned soups, salted nuts, canned vegetables and fast food.
Low-Protein Diet
Kidneys filter waste products from the blood so they do not accumulate and cause serious complications. One of the waste products, creatinine, forms when the body breaks down protein molecules. Damaged kidneys do not filter this waste product out of the blood as efficiently as they should. Patients following a low-protein diet for kidney disease limit their protein intake by eating smaller portions of high-protein foods or avoiding some high-protein foods. The Medical College of Wisconsin recommends that kidney disease patients limit their consumption of meat, eggs, dairy products and poultry and replace them with whole grains, vegetables, pinto beans and navy beans.
Low-Potassium Diet
Potassium has several functions in the body. The Linus Pauling Institute at Oregon State University explains that this electrolyte works with sodium to create electrical potential in the cells. Potassium also helps enzymes--substances that speed up chemical reactions--carry out their functions. As kidney disease progresses, the kidneys do not maintain normal levels of potassium in the blood. Those following a low-potassium diet limit their intake of foods high in this mineral. High-potassium foods include chocolate, coffee, oranges, bananas, potatoes, broccoli, cantaloupe, apricots and mushrooms. Low-potassium alternatives include cherries, cucumber, grapes, beans, apples, onions, watermelon, cranberries, lettuce and noodles.
Low-Phosphorus Diet
Phosphorus plays a role in generating energy, moving the muscles, maintaining normal pH balance, forming healthy teeth and bones, producing hormones and delivering oxygen to the cells of the body. Damaged kidneys do not remove enough phosphorus from the blood, allowing levels of this mineral to build up in the body. This leads to low calcium levels, itching, bone pain, heart problems and excess levels of parathyroid hormone, according to the Davita website. Replacing high-phosphorus foods with low-phosphorus alternatives prevents this from occurring. High-phosphorus foods to limit include chocolate, cola drinks, cheese, nuts, whole-grain bread, dried beans, peanut butter and processed meats. Alternatives to these foods include sour cream, clear sodas, gelatin, hard candy, angel food cake, white rice and fresh or frozen meats.
