The National Institute of Diabetes, Digestive and Kidney Diseases, NIDDKD, explains that when the kidneys are diseased, their ability to filter urea, potassium, phosphorus and sodium from the blood becomes compromised. This causes toxic substances to build up in the blood, a condition otherwise known as uremia. A healthy diet for kidney patients is one that compensates for this.
Warning
Patients should never change their diets without consulting a nephrologist first. A healthy diet for kidney disease patients is determined by the patients' individual urinalysis and blood work, as well as their blood pressure and special circumstances such as age or whether they are on dialysis. Making changes without professional advice can further injure a patient's already fragile health.
Controversy
The NIDDKS explains that high urine protein--also called proteinuria--is a red flag for kidney disease. Independently from any other factor, proteinuria contributes to the progression of kidney disease because proteins are very large molecules that damage the very tiny filters in the kidneys. It remains controversial whether protein restriction is part of a healthy diet for kidney disease. A 2009 paper published in the "Cochrane Database of Systematic Reviews" looked at results of 10 studies and concluded that protein restrictions slow the progression of kidney disease. However, this conclusion is by no means unanimous. Some particular groups of kidney patients, such as children and dialysis patients, could be hurt by protein restriction. A sensible approach is to consult a nephrologist as to whether protein restriction should be part of a healthy diet for a particular patient.
Cardiac Issues
The National Kidney Foundation reports that heart disease is the leading cause of death in kidney patients. Accordingly, it recommends that kidney patients eat a diet low in saturated fats. Restricting sodium intake helps to control blood pressure, which is a problem for most kidney patients. The National Kidney Foundation recommends relying upon garlic, spices and vinegar to make foods more appetizing.
Special Consideration
Patients with advanced kidney disease are at risk for high levels of serum potassium. High serum potassium occurs because the kidneys get progressively unable to filter potassium from the blood. This can cause irregular heart beats and even heart attacks.
A healthy diet for kidney patients with high potassium will take this into account. Many fruits and vegetables are high potassium foods, as are all dried fruits. According to the National Kidney Foundation, good low potassium choices include berries of all kinds, pineapple, tangerines, asparagus, green beans, cauliflower and eggplant. White flour products are preferred over whole grain products as whole grain products have too much potassium to be included in a low potassium diet.
Bone Health
The kidneys of patients with advanced kidney disease filter phosphorus from the blood less effectively, which causes serum phosphorus levels to get too high. The National Kidney Foundation explains that when this happens, the excess phosphorus causes calcium to be leached from the bones, leaving bones permanently weakened. A healthy diet for patients who have high levels of serum phosphorus will compensate for this problem. The National Kidney Foundation explains that foods with unacceptably high levels of phosphorus include milk, hard cheeses, dark-colored sodas, cocoa, dried beans, chocolate and bran cereals. Healthy alternatives are non-dairy creamer, cream cheese, corn flakes, green beans and ginger ale.
References
- Cochrane Database of Systematic Reviews: Low Protein Diets for Chronic Kidney Disease in Non Diabetic Adults
- National Kidney Foundation: Chronic Kidney Disease--A Family Affair
- Minerals and Electrolyte Metabolism: The Effects of Dietary Protein Restriction on Chronic Progressive Renal Disease
- National Kidney Foundation: Cholesterol and Chronic Kidney Disease
- National Kidney Foundation: Chronic Kidney Disease
- National Kidney Foundation: Phosphorus and your CKD Diet
