End-Stage Renal Disease: Nutritional Considerations

• Weight maintenance and protein requirements: Protein and calorie needs are higher in patients with ESRD due to losses that occur during dialysis. If protein-calorie needs cannot be met with the usual diet, patients should be offered dietary supplements or, if necessary, tube feeding to achieve adequate protein and calorie intake.
  
• Sodium and potassium balance: ESRD patients should avoid high-sodium diets. Many patients on dialysis can effectively control blood pressure without drugs on a low-sodium (2 grams per day) diet.
  
  A high-potassium diet is normally desirable to control blood pressure and reduce risk for stroke; however, individuals with ESRD on hemodialysis cannot tolerate this diet because they are unable to excrete potassium. Therefore, ESRD patients may need to avoid such foods as bananas, melon, legumes, potatoes, tomatoes, pumpkin, winter squash, sweet potato, spinach, orange juice, milk, and bran cereal to prevent high potassium levels, which can result in life-threatening arrhythmias. In contrast, patients on peritoneal dialysis more often suffer from low potassium levels, requiring an increase in potassium-containing foods and even potassium supplementation.
  
• Fluid restriction: It is essential that ESRD patients restrict their fluid intake in order to control blood pressure and avoid heart failure. The typical fluid allowance for patients on dialysis is 700 to 1,000 milliliters a day.
  
• Phosphorus: Elevated blood phosphorus levels can increase risk of cardiovascular disease and death in ESRD patients. Patients should be careful to avoid phosphate intake from processed foods. In addition, too much protein intake (more than 50 grams per day) can increase phosphate levels.
• Micronutrient supplements: Micronutrient supplements are essential for ESRD patients. Individuals on dialysis commonly have deficiencies of vitamin C, folate, vitamin B₆, calcium, vitamin D, iron, zinc, and selenium. The National Kidney Foundation clinical practice guidelines for nutrition in chronic renal failure suggest that patients achieve 100 percent of the Dietary Reference Intakes (DRI) for vitamins A, C, E, K, thiamin (B₁), riboflavin (B₂), pyridoxine (B₆), vitamin B₁₂, and folic acid, as well as 100 percent of the DRI for copper and zinc. As a result of restricted intake of many foods and losses of water-soluble vitamins during dialysis, patients are usually given specially formulated vitamins.
  
  Certain other dietary supplements may be helpful. Supplementation with L-carnitine has been approved by the U.S. Food and Drug Administration to prevent and treat carnitine deficiency in dialysis patients. L-carnitine has also been found to improve fat metabolism, protein nutrition, antioxidant status, and anemia. Nevertheless, inadequate evidence exists for the routine use of carnitine in patients who do not show signs of deficiency. Both vitamin C (250 milligrams a day) and vitamin E (400 International Units a day) have proven effective for treating painful muscle cramps. However, additional clinical trials are required before these can be used as standard therapy.
  
• Saturated fat and cholesterol: Dialysis patients should follow a diet low in saturated fat and cholesterol. These patients are at high risk for development of coronary artery disease. They often have increased triglycerides and decreased HDL ("good") cholesterol. Although they must eat a relatively high-calorie diet, patients on dialysis should avoid foods that raise triglycerides and cholesterol concentrations (see Hyperlipidemia).