What is Chronic Kidney Disease?
Chronic kidney disease (CKD) is a long-term condition in which the kidneys gradually lose their ability to filter waste, balance fluids, and regulate essential minerals in the body. It typically develops over time due to conditions such as diabetes or high blood pressure. Without proper management, CKD can progress to kidney failure, requiring dialysis or a transplant.
When someone is diagnosed with CKD, nutrition becomes a key part of treatment. A kidney-friendly diet can help slow the progression of CKD and manage symptoms. But once the kidney fails, the patient is now at end-stage renal disease (ESRD), and dialysis begins. Nutrition needs can immediately shift dramatically, and what worked before dialysis may no longer be right for the body’s new demands.
So, what changes and why?
Nutrition in Chronic Kidney Disease (Before Dialysis)
When your kidneys are still functioning, even at a reduced capacity, the main nutritional goal is to maintain kidney function for as long as possible. Specializing your diet helps to take some of the strain off of your kidneys by limiting the amount of waste buildup.
Some of the typical CKD nutrition goals include:
- Lower protein intake – Eating less protein reduces the amount of urea and waste the kidneys must filter out. Patients may be advised to eat modest amounts of protein from both plant and animal sources. The decreased amount of protein intake can cause muscle wasting and increase the risk of malnutrition, and fully preventing muscle loss might not be possible for individuals. Current guidelines advocate for those in the early stages of Chronic Kidney Disease to maintain a protein intake of 0.4 – 0.6 g / kg of body weight per day. Maintaining physical activity can also slow the progress of muscle loss.
- Limit sodium – Too much salt can raise blood pressure and worsen fluid retention. It also indirectly leads to greater fluid buildup as salty foods tend to increase thirst.
- Watch potassium and phosphorus – If kidney function declines, the body struggles to filter out and maintain the balance of these minerals.
- Control fluid intake – Not always strict in early CKD, but monitoring fluids can help with swelling and blood pressure. Over the progression of CKD, the kidneys will have a harder time producing urine, and excess water will remain in the body.
The main focus during this stage is often on slowing down kidney damage and keeping lab values stable.
Nutrition in Dialysis (After Kidneys Fail)
When someone starts on dialysis, their kidneys can no longer filter the blood enough on their own. Dialysis will remove the waste and extra fluid and take over the job of the kidneys, but this also marks a shift in one’s nutritional needs.
Some of the key nutrition differences include the following:
- Increased protein needs – Dialysis removes waste products from the blood, but it can also lead to the loss of some protein. On top of this, many dialysis patients have other health conditions that contribute to muscle breakdown, further raising their protein requirements. Adequate protein intake is essential to prevent malnutrition and support healthy albumin levels, which are closely monitored as a marker of nutritional status. Most patients are advised to consume about 1.0 – 1.2 grams of protein per kilogram of body weight each day, with recommended sources including lean meats, eggs, and select plant-based proteins. Kidney-friendly protein supplements are also encouraged.
- Phosphorus and potassium restrictions – These minerals build up quickly in the bloodstream and have a major impact on the heart and bone health. Elevated phosphorus levels can cause bone, heart, and joint diseases, itchy skin, mineral deposits in organs/soft tissue, or red eyes. Certain foods that are high in phosphorus include cheese, some nuts, chocolate, cola, and some whole grains. Elevated potassium levels can cause cardiac arrest, decreased heart rate, hospitalization, and muscle weakness. Foods high in potassium include bananas, oranges, potatoes, and tomatoes, and need to be limited.
- Tight fluid control – Dialysis can only remove a certain amount of fluid on each treatment. Drinking too much of any liquid, including water between treatments, can cause swelling throughout the body, raise blood pressure, and put strain on the heart and lungs. A common recommended amount of water per day is between 1 – 1.5 liters.
- Limit sodium – Too much salt in the diet can increase fluid retention, which can raise blood pressure. It also indirectly leads to greater fluid buildup as salty foods tend to increase thirst, causing patients to surpass their recommended fluid intake.
- Supplements – Vitamin and mineral supplements may be needed. Water-soluble vitamins like the B series, C, D, calcium, and iron are often lost during dialysis or lower in individuals with CKD. It is also important to avoid vitamins like A, E, and K that can cause complications at high doses.
Why the Shift in Nutrition Needs Happens with Renal Disease
The dietary changes from CKD to dialysis can feel confusing, but they make more sense when you look at the body’s needs at each particular point in time. During CKD, the kidneys are still filtering, so consuming less protein, vitamins, minerals, and fluid means less stress on them and delays ESRD. During dialysis, however, the machine completely takes over filtration. Because some protein is lost during treatment, the body needs more dietary protein to stay healthy and strong.
It’s a complete flip in philosophy: what once was restricted now becomes essential. Meanwhile, limits on sodium, potassium, phosphorus, and fluids often get tighter because the kidneys no longer provide a safety net to keep these values in balance.
The Takeaway
Nutrition in CKD and dialysis isn’t one-size-fits-all. What’s healthy for someone before dialysis may not be healthy once treatment starts. That’s why regular check-ins with a renal dietitian are so important. They can adjust meal plans based on lab results, dialysis type, and lifestyle.
If you or a loved one is moving from CKD to dialysis, remember:
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Protein needs will go up.
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Phosphorus, potassium, sodium, and fluids need careful monitoring.
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Supplements may be needed to replace vitamins lost during treatment.
Dialysis is a big change, but with the right nutrition approach, patients can feel stronger, protect their heart and bones, and get the most benefit from treatment.
References
Ikizler, T. A., Burrowes, J. D., Byham-Gray, L. D., Campbell, K. L., Carrero, J. J., Chan, W., … & Cuppari, L. (2020). KDOQI clinical practice guideline for nutrition in CKD: 2020 update. American Journal of Kidney Diseases, 76(3), S1-S107. doi: 10.1053/j.ajkd.2020.05.006.
MacLaughlin, H. L., Friedman, A. N., & Ikizler, T. A. (2022). Nutrition in kidney disease: core curriculum 2022. American Journal of Kidney Diseases, 79(3), 437-449. https://doi.org/10.1053/j.ajkd.2021.05.024
Massini, G., Caldiroli, L., Molinari, P., Carminati, F., Castellano, G., & Vettoretti, S. (2023) Nutritional strategies to prevent muscle loss and sarcopenia in chronic kidney disease: What do we currently know? Nutrients, 15(14), 3107. https://doi.org/10.3390/nu15143107
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). (2025). Healthy eating for adults with chronic kidney disease (CKD). U.S. Department of Health & Human Services. Retrieved, from https://www.niddk.nih.gov/health-information/kidney-disease/chronic-kidney-disease-ckd/healthy-eating-adults-chronic-kidney-disease
National Kidney Foundation. (2025). Vitamins and minerals in chronic kidney disease. Retrieved, from https://www.kidney.org/kidney-topics/vitamins-and-minerals-chronic-kidney-disease
Zha, Y., & Qian, Q. (2017). Protein Nutrition and Malnutrition in CKD and ESRD. Nutrients, 9(3), 208. https://doi.org/10.3390/nu9030208
