Home Topics Kidney FailureThe Renal Diet

The Renal Diet, Vitamin D & Erythropoietin Supplements

Treating kidney failure can be as simple as changing your diet, or as complex as long-term dialysis. Additionally, the underlying cause of the disease must be addressed, whether it is hypertension, infection, or other health complications. Following a careful diet and supplementing essential vitamins and hormones can often slow disease progression.

A renal diet can prevent or slow the loss of kidney function and reduce symptoms. Patients receiving dialysis treatment, in particular, should follow specific eating recommendations. A qualified dietician is often helpful to people living with renal failure.

The Renal Diet: Proteins

The renal diet calls for low protein, which helps reduce uremia symptoms such as nausea and vomiting. Uremia occurs when substances usually excreted in the urine build up in the blood stream. Calorie intake has to be monitored to balance the low protein levels. Protein in the renal diet should be high-quality protein, animal and/or vegetable. Good sources of high-quality protein include white fish, lean poultry, beef or lamb, eggs, low-fat cheese, whole grains. Low-quality proteins include smoked fish, bacon, ham, lunchmeats, and other high-fat or high-sodium proteins.

The Renal Diet: Sodium & Water

A renal diet also regulates the amount of water and salt consumed. Usually sodium (salt) levels must be restricted, but in a small number of cases, patients experience sodium deficiencies. The kidneys normally filter out extra sodium, but when kidney function is sub-par, sodium builds up in the system. A side effect of excess sodium is thirst, so ingesting too much sodium can make it difficult to stick to a fluid allowance. Regular blood tests are required to monitor sodium and water levels. Diuretics such as furosemide may be required to maintain an appropriate water balance.

The Renal Diet: Potassium

The kidneys are also responsible for filtering out too much potassium from the system. While potassium is necessary for nerve conduction and muscle contractions, too much potassium can cause an irregular heartbeat. The renal diet limits potassium intake by restricting high-potassium foods such as tuna, halibut, cooked beans, yam, sweet potatoes, beets, chard, Brussels sprouts, carrots, mushrooms, squash, cantaloupe, papaya, bananas, avocado, salt substitutes, chocolate.

Protecting Bone Density: Vitamin D & Phosphorus

The kidneys are responsible for activating vitamin D; low kidney function can cause vitamin D deficiencies. Since vitamin D is needed for the body to absorb calcium, inadequate vitamin D can result in osteodystrophy, or a weakening of the bones. Like osteoporosis, osteodystrophy has the effect of reducing bone density, leading to brittle, easily damaged bones. Supplementing the renal diet with vitamin D can slow bone density loss.

Phosphorus is also an important factor in calcium maintenance — the body tries to correct a high phosphorous level in the blood by pulling calcium from the bones. The kidneys filter phosphorus from the blood. The renal diet helps control phosphorus by limiting high-phosphorus foods such as bran, nuts, chocolate, sweetmeats, veal, canned fish, shellfish, yogurt, and cheeses.

Erythropoietin Supplements

Erythropoietin is a red blood cell growth factor that is produced by the kidneys. If erythropoietin levels drop because of decreased organ function, anemia (a lack of red blood cells) may occur, resulting in pallor, fatigue, and shortness of breath. Erythropoietin supplements help maintain proper red blood cell counts.

Increasing Caloric Intake in Kidney Failure

People in kidney failure commonly have poor appetites. It's important to take in enough calories for energy and to maintain body weight. When someone does not consume enough calories in their diet, fat and muscle will be metabolized to meet the body's caloric needs. If your appetite is poor and you have a hard time consuming enough calories, try these tricks to increase your calories while maintaining a healthy renal diet:

Use extra butter/margarine, salad dressing, mayonnaise, jam/jelly, syrup, honey.
Use half-and-half instead of milk in your cereal, coffee and tea.
Add a dollop of whipped topping to fruit and desserts.

Resources

Beers, M. H., & Berkow, R. (ed). Acute renal failure. The Merck Manual of Diagnosis and Therapy, 17th Edition. Merck Research Laboratories, NJ, 1999.

Beers, M. H., & Berkow, R. (ed). Chronic renal failure. The Merck Manual of Diagnosis and Therapy, 17th Edition. Merck Research Laboratories, NJ, 1999.

U.S. National Library of Medicine. (updated 2002). Acute renal failure. MedlinePlus Medical Encyclopedia.

U.S. National Library of Medicine. (updated 2003). Chronic renal failure. MedlinePlus Medical Encyclopedia.

Mayo Foundation for Medical Education and Research. (2004). Kidney failure. MayoClinic.com.