I have chronic kidney disease. Why is my nutrition so important?
If you have chronic kidney disease, your kidneys are not able to work as well as they should to remove waste from your blood. This allows waste to build up, which can lead to additional health problems and put extra stress on your kidneys.
Some of the waste in your blood comes from foods you eat, so following a special diet can help avoid a buildup. Reducing the stress on your kidneys can slow the progress of kidney disease.
I’m on dialysis. Do I still need to be concerned about nutrition?
Yes, you still need to watch what you eat. Dialysis can filter your blood very effectively, but it can’t remove all of the waste your body makes when it processes nutrients. You are at increased risk of waste levels rising between your dialysis sessions.
What foods add to the buildup up of waste in my blood?
Some of the waste that can build up in your blood comes from nutrients in the food you eat. Your body actually needs most of these nutrients for its day-to-day functions. But when your kidneys aren’t working well, certain nutrients can become a problem.
Phosphorous. Phosphorous is a mineral that can help keep bones healthy and strong. However, even in early stages of chronic kidney disease, the level of phosphorous in your blood can become too high. A high level of phosphorous can cause itchy skin. It can also cause your bones to lose calcium. If this happens, your bones will get weaker and more brittle. You also have a greater risk of developing osteoporosis.
Foods that are high in phosphorous include the following:
- Dairy products, such as milk, cheese, yogurt and ice cream
- Dried beans and peas, such as kidney beans, split peas and lentils
- Nuts and peanut butter
- Drinks like beer, cola and hot cocoa
If your phosphorous level is too high even after you change your diet, your doctor may prescribe a medicine to lower it.
Calcium. You need calcium to build strong bones. Unfortunately, foods that contain calcium often also contain phosphorous. If you have chronic kidney disease, you may need to take calcium supplements that are phosphorous-free. Your doctor may also prescribe a special type of vitamin D to help your body absorb calcium.
Protein. You need protein to build and maintain healthy muscles, bones, skin and blood. Protein also helps your body fight infection and heal wounds. When protein breaks down, it turns into waste products. Kidneys damaged by disease aren’t able to stop this waste from building up in the blood.
Potassium. Potassium is a mineral that helps your muscles and heart work properly. It is found in foods such as bananas, potatoes, tomatoes, avocados and melons. Having too much or too little potassium in your blood can cause serious problems. You may need to watch your potassium intake. Your doctor will determine whether you need to change the amount of potassium in your diet. This will depend on the stage of your kidney disease and whether you are taking medicine to help lower your potassium level.
Sodium. If you take in too much sodium (salt), you may retain fluid. This extra fluid can raise your blood pressure, putting stress on your heart and kidneys.
Check food labels for sodium. Packaged and processed foods are often high in sodium. You may know that foods such as soy sauce, processed meats, crackers and potato chips contain a lot of sodium. But you may not realize how much sodium is in foods like bread, canned vegetables, soups and cheese. Look for sodium-free or low-sodium foods.
Don’t add salt to your food. Try different seasonings, such as lemon juice, hot pepper sauce and salt-free seasonings. Avoid salt substitutes. They often contain high levels of potassium.
Fluids. If you have trouble getting rid of fluid from your body, you need to be careful about how much fluid you drink. Too much fluid can put additional strain on your kidneys.
Calories. You need to take in the right amount of calories to maintain a healthy weight and support your body’s functions. This can be challenging for people who have chronic kidney disease. Limiting the amount of protein, dairy, salt and certain nutrients in your diet reduces your food choices. Foods you used to eat may no longer be healthy options. Also, your appetite may be affected by chronic kidney disease. Even if it’s fine to eat certain foods you used to enjoy, they may not have the same appeal.
Your family doctor can help you make a diet plan that supports your kidney health. This is important because your diet may need to change as your kidney disease and the medicines you take change. Your doctor may recommend that you work with a registered dietitian to be sure you get the right amount of calories each day and avoid problems.
To increase your calorie intake, your doctor or dietitian may suggest adding simple carbohydrates, such as those found in hard candy, honey and jelly. Fats can be a good source of calories, but saturated fats increase your risk of cardiovascular disease. Instead, choose monounsaturated or polyunsaturated fats, such as olive oil or canola oil. These “good” fats are better for your cardiovascular health.
How can I track how my diet is affecting my kidneys?
A number of tests are available to track how well your kidneys are working and whether your diet is reducing the stress on your kidneys.
To measure how well your kidneys are filtering waste from your blood, your doctor may estimate your glomerular filtration rate (eGFR). This test evaluates the amount of creatinine (a kind of waste) in your blood. A declining eGFR indicates that your kidney function is getting worse. Other changes in your diet and/or medication may be necessary.
A simple dipstick urine test can reveal whether your kidneys are losing function. This test measures albumin and other protein wastes that build up when the kidneys aren’t working well.
The serum albumin test is a blood test that shows whether you are taking in enough protein and calories. If you’re not, you may be at risk of infections and you may not feel well overall.
The normalized protein nitrogen appearance (nPNA) test measures your protein balance to determine whether you are getting enough protein. This test involves a blood and urine sample.
The blood urea nitrogen (BUN) test measures the level of urea in the blood. Urea is one of the wastes left over when your body breaks down protein. A high BUN level may indicate that you are taking in too much protein.
Your doctor may also do a physical exam and ask some questions to identify any problems with your diet. He or she will want to know about any changes in your weight or your body fat and muscle. Your doctor may also ask about the amount of food you eat, as well as your activity and energy levels.
This content was developed with general underwriting support from Nature Made®.
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National Institute of Diabetes and Digestive and Kidney Diseases. Nutrition of Later Chronic Kidney Disease in Adults. Accessed August 07, 2011
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National Kidney & Urologic Diseases Information Clearinghouse (NKUDIC). The Kidneys and How They Work. Accessed August 07, 2011
National Kidney Disease Education Program. Testing for Kidney Disease. Accessed August 07, 2011
National Kidney Foundation. Glomerular Filtration Rate (GFR). Accessed August 07, 2011
National Kidney Foundation. Nutrition and Chronic Kidney Disease. Accessed August 07, 2011
Copyright © American Academy of Family Physicians
This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.