Eating well when you have kidney disease
Watching your intake of sodium, phosphorus, protein and potassium are among the dietary changes you'll need to make if you have chronic kidney disease.
If you have chronic kidney disease (CKD), one of the most important parts of your treatment plan isn't in your medicine cabinet or at your doctor's office.
It's in your refrigerator.
"Managing your diet is such an intricate part of staying healthy and succeeding with kidney disease," says Lisa Gutekunst, RD, a past chair of the National Kidney Foundation's (NKF) Council on Renal Nutrition. "People with CKD need to adjust their diets to take into account what their kidneys are no longer doing."
A faulty filter
Healthy kidneys filter waste products from the blood. These products then pass out of the body in urine. Kidneys also help to regulate other things in the blood, including minerals (such as calcium, phosphorus, sodium and potassium).
When kidneys fail, waste can build up in the body and minerals can get out of balance. This can lead to a variety of problems. For example, too much sodium or potassium in the blood can cause serious heart problems. Too much phosphorus leaches calcium from bones, making them weaker and more breakable. And too much urea nitrogen (a normal byproduct of protein) can cause nausea, confusion and dizziness.
4 ingredients to watch
In general, people with CKD need to work to control their intake of the following four ingredients:
1. Sodium. People with kidney disease should get no more than 1,500 milligrams of sodium daily, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). To reduce sodium intake:
- Check labels. Look for sodium-free or low-sodium food products. And remember: "Just because it says low salt does not mean low sodium," Gutekunst says. Other ingredients, such as monosodium glutamate (MSG) also contain sodium.
- Add flavor with spices. To enhance flavor, use nonsodium ingredients such as fresh spices, herbs, lemon juice and hot pepper sauce instead of salt. Be careful with salt substitutes, Gutekunst warns. They may be high in potassium, another nutrient that people with CKD need to watch.
- Limit processed foods, such as canned foods, snack foods, some frozen foods and most processed meats, which are often high in added sodium.
2. Phosphorus. Kidney disease interferes with the body's ability to get rid of phosphorus, so people with CKD should limit their intake of the nutrient, the NIDDK recommends.
Phosphorus is found naturally in foods such as dairy products, beans, peas and nuts. But Gutekunst says that phosphate additives are more concerning for people with CKD than phosphorus that occurs naturally.
That's because added phosphate is very common and is more readily absorbed by the body than naturally occurring phosphorus.
Phosphate is added to a variety of foods to improve color, flavor and malleability. For example, it's injected into some fresh and frozen meats, and it can also be found in many fast foods, breads and cereals. And all colas have phosphoric acid.
"Check the ingredient list for any word with the letters phos," Gutekunst says. Examples include pyrophosphate or potassium tripolyphosphate. People with CKD should avoid foods with these ingredients, she recommends.
3. Protein. Another job of the kidneys is to help remove blood waste products of protein. To help keep these waste products from building up, people with CKD typically need to cut back on the amount of protein in their diets.
According to the NIDDK, most people (including those who don't have CKD) can get enough protein each day by eating two 3-ounce portions of high-quality protein such as fish, chicken, red meat, eggs and dairy products.
Many Americans are accustomed to eating more protein than this, so it can be challenging to make this adjustment and still feel full. Gutekunst and the NKF offer these tips for limiting protein without feeling hungry:
- Build sandwiches with thin-sliced meat, thick slices of flavorful bread and plenty of fresh vegetables.
- Take the focus off of meat in main dishes. For example, make rice, pasta, salads and casseroles with small amounts of meat, or serve meat as a side dish and a vegetable or grain as your main dish.
- Eat extra servings of the nonprotein part of your meal.
- Eat low-protein snacks throughout the day.
Soy is a good high-quality protein for vegetarians, Gutekunst says. But not much research has been done on vegetarian diets in general for people with CKD. So vegetarians should talk with their doctors about their protein needs.You'll also need to talk with your doctor about your protein needs if you are on dialysis. Most people on dialysis should eat as much high-quality protein as they can, according to the NIDDK.
4. Potassium. This nutrient, found in foods such as bananas, potatoes, tomatoes, milk and meat, helps muscles work properly. How much potassium you need depends on how advanced your CKD is and what kind of medicine you're taking. And your needs may change over time.
"Try not to get frustrated with your doctor if at one appointment he says you need more potassium and at the next appointment he says to cut back," Gutekunst says. Lab tests will help your doctor know whether you need more or less potassium or a medicine or supplement to help regulate your potassium levels.
In addition to the tips listed above, you may need to watch your calorie or fluid intake. You should also choose a heart-healthy diet, limiting foods high in saturated and trans fats, because heart disease is common among people with CKD, according to Gutekunst.
Work with an expert
Because the dietary needs of people with CKD can be quite complicated, it can be helpful to work with a registered dietitian (RD) who specializes in renal (kidney) nutrition.
"Speak with nutritional and medical experts about your diet," Gutekunst says. "Don't get advice from the TV or internet."
You can find more information about kidney disease and nutrition at kidney.org.