Nutrition and Kidney Disease
Your kidneys help keep you healthy by removing waste products and extra fluid from your blood. These waste products pass out of your body in your urine. Waste products come from what you eat and drink every day.
The kidneys also help control the amount of sodium, phosphorus (FOS-forus), and potassium (po-TAS-see-um) in your blood.
As the kidney(s) fail, they may lose the ability to perform these important functions. Some waste products and fluids then stay in your blood. A special diet may be needed to help control the waste products and fluid.
Your diet needs may change as your kidney function changes. The results of your blood tests will help the doctor prescribe the diet that you need.
Your body needs protein every day for growth, building muscles, and repairing body tissues.
Protein foods include eggs, meat, fish, and poultry. After your body uses the protein in the foods you eat, a waste product called urea (your-EE-a) is made.
When your kidneys fail, they can no longer remove urea normally. In early kidney failure, you may need to cut down the amount of protein that you eat. That way, your kidneys will not have to work so hard.
Also, less urea will build up in your blood.
Phosphorus is a mineral that helps keep bones strong. Calcium also helps keep bones strong.
The kidneys usually help to keep phosphorus levels within normal limits. As the kidneys stop working properly, they can no longer keep up normal phosphorus levels. This causes the phosphorus level in your blood to become too high.
A high blood phosphorus level can cause you to lose calcium from your bones. Your bones may become weak and break more easily.
To help control the phosphorus level in your blood, you may be asked to eat fewer foods that are high in phosphorus. This means you should limit milk, cheese, ice cream, yogurt, nuts, legumes, peanut butter, and cola soft drinks.
The doctor also may prescribe medicines called “phosphorus binders.” These medicines help control the amount of phosphorus you absorb from your food. It is important that you take these medicines as directed.
A high sodium diet may lead to high blood pressure or may make high blood pressure difficult to control.
Because many people with kidney disease have high blood pressure,you may be asked to limit the amount of sodium you eat.
Table salt, salted snacks, canned soups and vegetables, pickles, processed meats (bacon, ham, deli meats, canned meats), and convenience foods may need to be limited.
Do NOT use salt substitutes without checking with your doctor or dietitian. Sometimes salt substitutes are high in potassium.
Potassium is a mineral found in many of the foods that we eat.
In the body, potassium helps nerves and muscles — especially the heart — to work right. If potassium levels get too high, muscles become weak. The heart may slow down and even stop beating.
Healthy kidneys help keep potassium levels from getting too high by taking excess potassium out of our blood.
As kidneys fail, they may lose their ability to keep potassium within normal limits. If potassium levels are high, you may need to limit the high potassium foods that you eat.
Many fruits and vegetables are high in potassium. You may need to limit oranges, orange juice, bananas, melons, potatoes, sweet potatoes, tomatoes, and spinach.
Your kidneys help to remove excess fluid from your body. The fluid is excreted in your urine.
Most people with early kidney failure do not need to limit the fluid that they drink each day. You should drink when you are thirsty and avoid dehydration, which is bad for kidney function.
If your kidney failure progresses, you may be asked to limit the amount of fluid you take in each day. Fluids are foods that are liquid at body temperature, for example, ice, ice cream, gelatin, water, coffee, tea, fruit juices, vegetable juices, soup, and soda.
It is important to get enough calories to maintain a healthy weight when you have kidney disease.
Calories provide your body with the energy it needs to keep up with your daily activities. If you do not get enough calories every day, you may lose weight and muscle mass.
Over time, not getting enough calories may cause you to become too thin (or malnourished). Let your doctor know if you are having trouble eating enough to maintain a healthy weight.
Renal (Kidney) Diet
A renal (REE-nal) diet can help control the build-up of waste products and fluid in your blood. It also may help decrease the work load of your kidneys and slow down the loss of kidney function.
The goal of the renal diet is to keep you healthy. No single diet is right for everyone who has kidney disease.
Your doctor may recommend a renal diet, depending on the stage of your disease and the results of your laboratory tests.
If this diet is ordered, your doctor may want you to see a renal dietitian. This person has special training in diets for people with kidney disease.