Phosphorus & Potassium Diet for Severe Kidney Disease

Severe kidney disease impairs the normal function of the kidneys, making it difficult for these organs to maintain normal balances of minerals and electrolytes in the body. Although the human body requires potassium and phosphorus from dietary sources, people with kidney disease need to reduce their consumption of these minerals. Eating foods rich in phosphorus or potassium could result in dangerously high levels of these substances, compromising kidney function.

Benefits

Phosphorus provides some of the structure for the bones in the form of a substance called hydroxyapatite. Phosphorus also helps form the structure of the cell membranes and plays a role in the use of enzymes and hormones in the body. Potassium helps the body regulate the acid-base balance, plays a role in muscle development and body growth and helps the body manufacture proteins.

Significance

A diet low in phosphorus and potassium helps patients with severe kidney disease avoid medical complications. Doctors refer to excess phosphorus in the blood as hyperphosphatemia. Because phosphorus plays a role in regulating calcium levels, hyperphosphatemia may lead to low calcium levels in the blood. Low calcium levels cause muscle cramps, muscle twitching, anxiety, irritability, confusion, dry skin, hair loss, abdominal pain, difficulty breathing and wheezing. If left untreated, low blood calcium levels cause abnormal heart rhythms, heart enlargement and congestive heart failure, according to Diseases of Bone and Mineral Metabolism on the Endo Text website.

Increased blood potassium levels, or hyperkalemia, also have serious health consequences. High potassium levels cause irregular heartbeat, nausea, weak pulse or slow pulse. Uncontrolled hyperkalemia may also cause a loss of muscular control, abnormal heart rhythm and cardiac arrest, according to National Institutes of Health's website Medline Plus.

Foods to Avoid

People with severe kidney disease should avoid foods high in phosphorus and potassium. High-phosphorus foods to avoid include peanut butter, sardines, cola, cheese, nuts, beer, caramel candies and ice cream. Foods with high levels of potassium include avocado, nectarine, banana, kiwifruit, prune juice, raisins, nuts, potato chips, potatoes, tomatoes, sweet potatoes and pumpkin. Limit your consumption of foods with even low to moderate levels of phosphorus and potassium.

Alternatives

Replace high-phosphorus and high-potassium foods with foods that do not contain high levels of these minerals. The Medical College of Wisconsin recommends broccoli, zucchini, hard candy, non-dairy milk substitute, non-cola soft drinks and sherbet as alternatives to high-phosphorus foods. Replace high-potassium foods with apples, wax beans, grapes, green beans, rice, pears, cucumbers, onions, cranberries, watermelon, bread, cherries and carrots.

Considerations

In addition to reduced consumption of phosphorus and potassium, a renal diet restricts the intake of protein and sodium. The metabolism of protein results in the production of creatinine, a waste product. Because damaged kidneys do not filter waste properly, creatinine builds up and causes symptoms such as itching, nausea and vomiting. Too much sodium causes fluid retention, swelling and an increase in blood volume. Increased blood volume makes the heart work harder to pump blood, leading to high blood pressure. Patients with severe kidney disease may also have to limit their fluid intake in order to reduce swelling.