The kidneys are the filtering system of the body. Waste products are filtered and then eliminated from the blood in the urine. The kidneys also maintain the balance of necessary substances such as water, sodium, and potassium. An excess of any of these substances can be harmful. Certain diseases, including diabetes and hypertension, can lead to a decrease in kidney function or renal failure. Depending on the type of renal failure one has, nutrition treatment will be different. Patients will look to the nursing professional to answer questions about diet, especially if the dietitian is not included in the patient’s care prior to discharge. Awareness of the difference between pre-dialysis renal failure and end-stage renal disease with dialysis and their diet implications is necessary.
Renal failure can happen suddenly (acute renal failure), but more commonly occurs gradually over time (chronic renal failure). Acute renal failure (ARF) occurs most often as a complication from a serious illness and does not require long-term dialysis. ARF is often a temporary condition and with proper treatment often can be reversed with no permanent or serious damage to the kidneys. Chronic renal failure (CRF) is a progressive loss of the kidney’s ability to excrete waste products. CRF slowly worsens and most often is a result of another disease process that damages the kidneys over time, such as high blood pressure, diabetes, autoimmune disorders such as lupus, and diseases of the heart or lungs. Unlike acute renal failure, CRF is not reversible. This gradual progression leads to end-stage renal disease, which requires long-term dialysis treatments.
The therapeutic nutrition provided will depend on the type of renal failure the patient develops. In acute renal failure (pre-dialysis) nutrition guidelines are very strict. The protein content of the patient’s diet is restricted severely until the renal labs return to normal. Sodium, fluids, potassium and phosphorus are restricted in the diet during the duration of the acute renal failure. The ultimate goal is to restore renal function and loosen these diet restrictions prior to discharge.
Chronic renal failure nutrition therapy will be the same until it progresses to end-stage renal disease and the patient starts long term dialysis treatments. Once dialysis starts, protein is no longer restricted as with ARF or CRF. Patients receive dialysis, which cleanses their blood, three times per week for at least three hours at each session. It is crucial to ensure that the patient is receiving adequate protein during dialysis to compensate for protein losses during the process. Sodium and fluids are still restricted to limit weight gain between dialysis treatments. Phosphorus is limited to avoid increased phosphorus blood levels which may interact with calcium to weaken bones. Phosphorus also has negative effects on heart tissue, blood vessels, and lungs. Patients take phosphorus binders with meals to help rid the body of excess phosphorus. Potassium is also restricted in the diet. Excess serum potassium can negatively affect heart rhythms.
Patients have blood drawn monthly to check renal laboratory values. The outpatient dialysis dietitian will review lab results with the patient and make any necessary nutrition treatment changes at that time. During a post-discharge outpatient appointment the dietitian will review the patient’s food records and answer questions in more detail. Below is a list of nutrition guidelines to give patients prior to discharge to help them feel more comfortable with their home diet.
Pre-Dialysis Renal Failure Survival Skills
- Protein needs to be restricted to two ounces of meat at lunch and supper.
- Restrict milk to one-half cup per day.
- Limit sodium and high-sodium foods.
- Limit the amount of fluids consumed daily. The physician may order a fluid restriction. This could range from 1200-2000 ml (40-60 ounces) per day.
- Reduce the amount of potassium-rich fruits and vegetables consumed daily. Examples include: tomatoes, vegetable juice cocktails, sweet potatoes, bananas, melons, and oranges.
- Reduce whole grains and bran, cheese, and beans to decrease phosphorus consumption.
End-Stage Renal Disease with Dialysis Survival Skills
- Increase the amount of protein eaten – make sure you have meat with every meal.
- Limit sodium and high-sodium foods.
- Fluids need to be limited to the amount ordered by the physician.
- Limit high-phosphorus foods. Take phosphorus binders as ordered.
- Limit high-potassium foods.