Food basics
Kidney-Friendly Eating Basics: Potassium, Phosphorus and Sodium
This article is general information. Your nephrologist or renal dietitian knows your lab results and can tell you what is right for you.
Food matters in kidney care, but it is also the area where advice is most personal. This article explains the basic terms official sources use. It gives no meal plan and no personal limits. Your doctor and a registered dietitian, ideally one who works with kidney disease, set those for you based on your blood tests.
Early on, there may be few limits
NIDDK says that in the early stages of chronic kidney disease (CKD) you may have few limits on what you can eat and drink, and that as the disease advances and nutritional needs change, more changes may be needed. It does not give stage-based numbers, because needs vary from person to person.
Sodium
NIDDK cites the general adult limit from the 2020–2025 Dietary Guidelines: no more than 2,300 milligrams of sodium per day, and says many people with CKD need to limit sodium even more, with an individual limit set by the health care professional. On a food label, NIDDK says a % Daily Value of 20% or more means high in sodium and 5% or less means low. The National Kidney Foundation (NKF) notes that cutting sodium is broadly recommended, and mentions under 2300 mg a day when there is high blood pressure.
Potassium
NIDDK lists high potassium among the possible complications of CKD. It gives no numeric limit: your blood level is measured with a blood test, and you work with a dietitian or health care professional to find your target. It mentions steps that may be recommended, such as limiting serving sizes, avoiding salt substitutes made with potassium chloride, and draining canned fruits and vegetables. Some medicines and skipped dialysis sessions can also raise potassium, and potassium binders may be prescribed.
Phosphorus
The NKF describes mineral and bone disorder, an imbalance of calcium and phosphorus, as a possible complication of CKD. NIDDK gives no numeric phosphorus limit: a blood test measures your level. Suggested steps include limiting processed foods that contain phosphorus additives and choosing smaller portions of high-phosphorus foods. As kidney disease advances, a phosphate binder taken with meals may be needed.
Protein and fluids
NIDDK says some people with CKD may need to consume moderate amounts of protein, and that too little protein can lead to malnutrition. Needs may change over time, and people on dialysis may need more. For fluids, it advises talking with your health care professional about how much you should have each day, and contacting them if you notice swelling in the face, arms, legs or abdomen.
A registered dietitian can help
NIDDK says a registered dietitian can provide medical nutrition therapy, which is nutrition counseling to meet medical goals, and that Medicare covers it with a written referral from a doctor. Ask your doctor whether it is right for you. A list of questions for the visit is in Questions to Ask Your Nephrologist.
From information to the kitchen
Understanding the terms is one thing; putting them on the plate every day is another. That is where our community and our cookbooks come in: our Facebook group is a place to share everyday meal ideas, and Don’s Food Press publishes cookbooks with easy, kidney-friendly recipes for stage 3. Our articles on stage 3 and on first steps after a diagnosis explain the medical side.
Related reading
Sources
- NIDDK: Healthy Eating for Adults With Chronic Kidney Disease (reviewed January 2025)
- National Kidney Foundation: Stage G3a Chronic Kidney Disease (CKD)
- National Kidney Foundation: First Steps After Diagnosis of CKD
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