Newly diagnosed kidney patients are usually bursting with questions about diet. Dietary changes may not be necessary in the early stages of disease, especially if urine protein levels are low and hypertension is not a problem. However, as kidney disease progresses to stage 3, patients can feel better and have healthier outcomes if they follow their nephrologist's suggestions regarding diet.
Stage 3
The National Kidney Foundation describes five different stages of chronic kidney disease. These range from stage 1, in which kidney function is normal, to stage 5, which is associated with end-stage kidney disease. Patients with stage 3 have moderate kidney damage. Their glomerular filtration rate, or GFR, is 30 to 60 mL per minute. The GFR describes how much blood the kidneys filter every minute.
Monitoring
Patients with stage 3 kidney disease are monitored regularly. In addition to blood pressure assessments, blood work and urinalysis are performed at regular intervals. Specific blood tests include serum creatinine, urea, phosphorus, potassium and other tests. Urine tests, also called urinalysis, include urine protein, red blood cells, white blood cells, specific gravity and others. The outcome of this monitoring determines whether dietary restrictions are necessary.
Sodium
Hypertension is endemic among kidney patients so a low sodium diet is generally recommended for stage 3 patients. Nephrologists or renal dietitians suggest particular sodium targets. If potassium is not a problem, potassium-based salt substitutes may be acceptable. However, if your potassium levels are too high, these substitutes may be dangerous. Under these circumstances, spices and herbs may be used to season food.
Potassium
High serum levels of potassium often become problematic as chronic disease progresses toward end stage disease. If serum levels of potassium exceed 5.0 mg/dL, nephrologists recommend that patients limit their intakes of potassium. Potassium restriction is important because high levels of potassium cause nerves to misfire, which in turn, causes irregular heartbeats and even heart attacks. Identifying which foods are high in potassium is very difficult so using a potassium counter, like the one provided by the USDA, is very helpful.
Phosphorus
Patients with advanced kidney disease often have high serum phosphorus. High serum potassium starts to pull calcium from the bones, weakening them and making the patient more vulnerable to fractures. If you have high serum phosphorus, your nephrologist may suggest that you avoid dairy products, bran, chocolate and beer.
References
- National Kidney Foundation: Glomerular Filtration Rate
- National Institute for Diabetes and Digestive and Kidney Diseases; High Blood Pressure and Kidney Disease; July 2008
- National Kidney Foundation: Phosphorus and your CKD Diet
- National Kidney Foundation: Potassium and your CKD Diet
- USDA: Nutrient Data Laboratory
- National Institute for Diabetes and Digestive and Kidney Diseases; Chronic Kidney Disease-Mineral and Bone Disorder; Feb. 2009
