Almost all kidney patients ask about whether dietary changes can reverse their disease or slow its progression. Some patients seem to think that the more extreme a dietary approach, the greater its likelihood of success.
Other than following a sensible, heart-healthy regime--which most of us should do anyway--there are no dietary restrictions until kidney function gets so reduced that certain electrolytes such as potassium and phosphorus start getting out of kilter. At that point, diet is governed by the patient's blood work results. Observing dietary restrictions before this occurs is premature and does not prevent subsequent problems.
Heart-Healthy Diet
According to the National Kidney Foundation, heart disease is the leading cause of death among kidney patients. Given that kidney patients are at risk for cardiac disease, a heart-healthy diet such as recommended by the American Heart Association is advised for all patients. This will help with blood pressure and cholesterol, which are problems for most kidney patients.
Heart-healthy diets involve eating less sodium and fat. Patients should ask their nephrologist how much sodium is reasonable and what types and amounts of fruits and vegetables can be safely tolerated.
Prevention
Healthy kidneys keep serum potassium levels in a very narrow range. The kidneys may no longer be able to perform this important function when renal function declines. If potassium levels are too high, cardiac arrhythmias and heart attacks can be prevented by minimizing the dietary potassium.
High-potassium foods should be eaten in very small quantities. In some instances a high-potassium food can be converted into a moderate or low-potassium food by cutting it up and soaking it in water for a few hours to leach the potassium from the food. This works with root vegetables such as potatoes and carrots. These practices prevent serious cardiac complications.
The normal range of potassium for most people is 3.7 to 5.2 milli-equivalents/liter. Patients should ask their nephrologists whether their numbers are in an acceptable range. Requesting a consult with a dietician can be very helpful.
Benefits
Controlling levels of dietary phosphorus can reap multiple benefits in the latter stages of kidney disease if serum levels of phosphorus becomes elevated. Symptoms of excess phosphorus include skin so itchy that it is maddening. Controlling dietary phosphorus can bring this symptom under control.
A second benefit is that controlling phosphorus helps preserve healthy bones. The National Institute of Diabetes, Digestive and Kidney Diseases explains that when serum phosphorus levels get too high, the parathyroid gland secretes a hormone that pulls calcium out of the bones. One way to prevent this from happening is to control dietary phosphorus. If necessary, phosphorus binders can be taken.
Since almost all foods contain phosphorus, this can be very challenging. Using a phosphorus counter like the one generated by the USDA National Nutrient Database is very helpful.
Protein
Medline Plus notes that many patients with chronic kidney disease suffer from nausea. This symptom often gets worse as patients approach renal failure. Some patients observe that lowering their protein intake helps control the nausea. This is not always the best approach because patients approaching end stage are often malnourished. Asking for a consult with a dietician can help patients reach transplant or dialysis in the best shape possible.
Warning
Kidney patients should not change their diets without consulting their nephrologists. Kidney disease is particularly complex and has many implications for diet. Taking the advice of well-meaning family and friends is often a mistake because many of the dietary considerations for kidney patients go against conventional dietary wisdom.
References
- National Institute of Diabetes, Digestive and Kidney Diseases: Eat Right to Feel Right on Hemodialysis
- National Kidne Foundation: Potassium and Your CKD Diet
- American Heart Association: Eat a Heart-Healthy Diet
- National Kidney Foundation: Chronic Kidney Disease (CKD)
- National Institute of Diabetes, Digestive and Kidney Diseases: Chronic Kidney Disease-Mineral and Bone Disorder
