When managing end-stage renal disease (ESRD) or chronic kidney disease (CKD), dietary adjustments are crucial. A renal diet aims to minimize waste in the blood, thereby reducing the workload on the kidneys. Protein intake is a key component of this diet, requiring careful consideration and often adjustment based on whether or not a patient is on dialysis. The most common question that dietitians hear from patients diagnosed with CKD is, “What should I eat?” It can seem confusing when you hear or read different things. This article provides a structured overview of protein sources suitable for a renal diet, addressing the specific needs of individuals with and without dialysis.
Understanding the Renal Diet
A renal diet is designed to manage the buildup of waste products in the blood that occurs when the kidneys are not functioning properly. Kidneys filter wastes created by the foods you eat to help to keep the right balance of nutrients and minerals in your blood and in your body. Renal diets minimize the amount of waste in the blood and decrease the amount of work the kidneys do. When you have chronic kidney disease (CKD), any stage of CKD, you lose the ability to get rid of nitrogenous protein waste from foods you eat or drink, and it starts to build up in your blood. This is called uremia. Symptoms of uremia include nausea, bad taste in the mouth, loss of appetite, and weakness.
Key components of a renal diet typically include managing the intake of sodium, potassium, phosphorus, calcium, and protein. As CKD advances, nutritional needs change. It’s essential to consult with a healthcare professional, ideally a registered dietitian, to create a personalized eating plan.
Protein Needs in CKD: Dialysis vs. No Dialysis
Protein is used to build muscle, heal, fight infection, and stay healthy. Protein needs vary based on your age, sex and overall general health. Protein in the diet comes from both animal and plant sources. The amount of protein required in a renal diet varies depending on whether the individual is undergoing dialysis.
CKD Without Dialysis: Limiting Protein Intake
For individuals with CKD who are not on dialysis, a lower protein diet is generally recommended. If you have CKD stages 1 or 2 (GFR of 60 or higher), eating less protein can slow down the progression of kidney disease. The more protein waste that needs to be removed, the harder the kidneys need to work to get rid of it. This can be stressful for your kidneys, causing them to wear out faster. Many studies suggest that limiting the amount of protein and including more plant-based foods in the diet may help slow the loss of kidney function.
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In general, for CKD stages 1 and 2, the current recommendation is to limit dietary protein to no more than 0.8 grams per kilogram of your ideal body weight. Once your glomerular filtration rate (GFR) starts to decline, it is better to get more plant-based proteins, as they break down to less urea than animal proteins. If you have CKD stages 3-5 (GFR 59 or lower), unfortunately, you will need to restrict your protein even more. Studies now show that limiting protein to 0.55-0.60 grams per kilogram of your body weight can delay decline in kidney function. If you are diabetic, 0.8-0.9 grams per kilogram of your ideal body weight is reasonable. Sometimes a doctor may prescribe keto acid analogues to meet protein requirements of very low-protein diets to prevent malnutrition.
The goal is to reduce the amount of waste the kidneys need to process, thus slowing the progression of kidney disease.
On Dialysis: Increasing Protein Intake
Once a person has started dialysis, a higher amount of protein in the diet is necessary to help maintain blood protein levels and improve health. On the other hand, once a person has started dialysis, a higher amount of protein in the diet is necessary to help maintain blood protein levels and improve health. Dialysis removes protein waste from the blood, so a low protein diet is no longer needed. Dialysis removes protein from the blood, so a low-protein diet is no longer necessary. In fact, dialysis patients often require more protein to compensate for what is lost during treatment.
High-Quality Protein Sources for a Renal Diet
Choosing the right protein sources is crucial for managing CKD. High-quality protein sources provide essential amino acids necessary for the body's functions while minimizing the strain on the kidneys. Protein comes from both animal sources - like beef, pork, poultry, eggs, fish, shellfish, and dairy - and plant sources, including beans, legumes, and tofu. Animal sources of protein have all the essential amino acids (the building blocks of protein). Animal sources of protein vary in their amount of fat, with fatty cuts of red meat, whole-milk dairy products, and egg yolks being the highest in saturated fat (less healthy for the heart). Fish, poultry, and low-fat or fat-free dairy products are lowest in saturated fat.
Animal-Based Protein Sources
Animal sources of protein are complete proteins, meaning they contain all essential amino acids. However, it's important to choose lean options to minimize saturated fat intake.
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- Lean Meats: Turkey or lean beef, both of these protein sources give you iron to help prevent anemia. A 3-ounce cooked burger has 21 grams of good-quality protein. NIDDK advises people with kidney disease to limit portions of meat and fish to 2-3 ounces, as high protein levels can make your kidneys work harder.
- Poultry: Protein from chicken can range from 14 to 28 grams. Two or three ounces (85 grams) of cooked, skinless chicken breast contains:sodium: 64 mgpotassium: 220 mgphosphorus: 196 mgprotein: 27 g. Use fresh meat products and avoid pre-made roasted chicken and other processed meats, which often contain large amounts of sodium and phosphorus.
- Fish: Fish, such as salmon, mackerel and rainbow trout, and even shrimp, are great protein choices. A 3-ounce portion of cooked fish has approximately 15-21 grams of protein. Sea bass is a fish option that provides high quality protein. It also contains healthy fats called omega-3s. Omega-3s may help prevent a range of diseases and boost the health of those living with long-term conditions.
- Egg Whites: Egg whites are a great, easy source of protein. Two large, raw egg whites (66 g) contain:sodium: 110 mgpotassium: 108 mgphosphorus: 10 mgprotein: 7 g. Egg whites provide a high quality, kidney-friendly source of protein that is low in phosphorus. Egg whites may be a better choice than whole eggs for people on a renal diet, as egg yolks can be high in phosphorus.
- Low-Phosphorus Dairy: Compared to milk, yogurt and cheese, cottage cheese is lower in potassium and phosphorus. When eaten as a meat replacement, Greek yogurt may work into your meal plan, with a cup adding 22 grams of protein to your diet.
Plant-Based Protein Sources
Plant sources of protein are low in one or more of the essential amino acids. Plant sources of protein include beans, lentils, nuts, peanut butter, seeds and whole grains. A plant-based diet can meet protein needs with careful planning by eating a variety of plant-based foods. Another bonus with plant proteins is that they are low in saturated fat and high in fiber. Plant-based protein like beans and nuts are easier on the kidneys than animal proteins like meat and dairy products. This is because plant proteins produce less acid in the body than meat proteins. More acid in body can damage the kidneys.
- Legumes: No-salt-added canned or cooked dried beans and peas. High-quality protein sources for vegetarians include lentils, seeds, tofu and whole grains.
- Tofu: Tofu, made from soy beans, comes in varying textures, and can be an acceptable protein alternative to meat, poultry and fish.
- Veggie Burgers and Meat Substitutes: Veggie burgers, veggie sausage and veggie crumbles are easy to find meat substitutes.
- Nuts and Seeds: Many nuts are high in phosphorus. Depending on the stage of your kidney disease, you may choose to eat nuts or limit them.If you choose to eat nuts, macadamia nuts are a delicious option for people with kidney problems. They’re lower in potassium and phosphorus than peanuts or almonds.They also provide healthy fats, folate (vitamin B), and the following minerals: calciummagnesiumcopperironmanganeseOne ounce (28 g) of macadamia nuts contains:sodium: 1.4 mgpotassium: 104 mgphosphorus: 53 mgprotein: 2 g.
Other Protein Sources
- Protein Powders and Liquids: Protein powders and liquids provide a concentrated protein source that can be added to foods or beverages.
- Kidney-Specific Nutrition Drinks: Nepro®, Suplena®, NovaSource Renal®, Nutren Renal® and ReGen® are some kidney-specific nutrition drinks available for dialysis diets or CKD non-dialysis diets that are also good sources of protein.
- Kidney-Friendly Bars: Pure Protein®, Premier Nutrition®, Balance Bars®, Zone Perfect®, EAS Myoplex®, ProMax®, PowerBar® and Atkins Advantage® offer several kidney-friendly bars.
Additional Dietary Considerations for Renal Patients
Besides protein, other dietary factors must be carefully managed in a renal diet.
Sodium Restriction
Healthy kidneys control how much sodium is in your body. If your kidneys do not work well, too much sodium can cause fluid buildup, swelling, higher blood pressure, and strain on your heart. Your dietitian or healthcare provider can tell you the right amount of sodium you should have each day. Limit sodium. Cut back on the salt you add during cooking and at the table. Also be sure to check food labels and choose the lower sodium items. Low sodium foods have no more than 140 milligrams of sodium per serving. Many ready-to-eat foods, vegan meats, and soy- and rice-based cheeses are high in sodium.
Potassium Management
Potassium is important for muscle function, including the heart muscle. Too much or too little potassium in the blood can be very dangerous. The amount of potassium you need is based on how well your kidneys are working and your medications. Your dietitian or healthcare provider can tell you about foods with potassium and the right amount for you to eat each day. Elevated blood sugars can also increase potassium levels. Some high-potassium foods include milk, meat, bananas, oranges and orange juice, cantaloupe, dried fruits, winter squash and salt substitutes. Be aware that many low-sodium foods contain added potassium chloride.
Phosphorus Control
As kidney function gets lower, extra phosphorus can start building up in the blood. High phosphorus levels can cause bones to get weaker. Your dietitian or healthcare provider can tell you if you need to limit goods that are high in phosphorus. Avoid processed foods that have additives with PHOS like disodium PHOSphate.
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Fluid Intake
Most people in the early stages of kidney disease do not need to limit how much fluid they drink. If you do not know your stage of kidney disease, ask your healthcare provider. If your kidney disease worsens, your dietitian or healthcare provider can let you know if you need to limit fluids and how much to drink each day. Fluids may need to be limited based on how much urine you make each day, and if fluid build-up in your body is causing swelling or stress on your heart or lungs.
Sample Meal Plan Adjustments
To illustrate how to apply these principles, consider the following meal plan adjustments:
- Swap High-Potassium Juices: If you drink orange juice to treat low blood sugar, switch to kidney-friendly apple or grape juice.
- Limit Processed Foods: Avoid processed foods that tend to have added sodium and phosphorus.
- Choose Low-Potassium Vegetables: Opt for low-potassium vegetables such as lettuce, green beans, cucumbers, asparagus, carrots, cauliflower, peas, zucchini, and radishes.
The Vegetarian Renal Diet
A kidney diet, also called a renal diet, is a key part of any treatment plan for chronic kidney disease. Today's kidney diets let vegetarians enjoy more foods than ever. Those foods include fruits, vegetables and plant proteins such as whole grains. But there's no one eating plan that works for every vegetarian with chronic kidney disease.
Protein. High-quality protein sources for vegetarians include lentils, seeds, tofu and whole grains. Phosphorus. If your body's phosphorus level is high, it may help to take in fewer foods and drinks that have phosphorus added to them. Phosphorus is added to highly processed items such as soft drinks, frozen food, snacks and processed cheeses. Dairy foods also are a source of phosphorus in a typical diet. If needed, you can replace dairy products with rice, almond or soy versions that haven't been enriched. Potassium. If your potassium level is high, it's helpful to work with a dietitian to spot sources of potassium within your diet. Just like phosphorus, potassium that is added to foods is better absorbed than is the potassium found in fruits and vegetables naturally. A dietitian can help prevent high potassium by focusing on other factors that can cause potassium in your blood to be high. Cooking foods in water, pressure cooking or cooking in the microwave can lower the potassium levels in foods. Be aware that many low-sodium foods contain added potassium chloride.
Importance of Consulting a Dietitian
The exact amount of protein you need depends on your body size, your nutritional status and your kidney problem. Since too little protein can lead to malnutrition at any stage of kidney disease, ask your healthcare professional about meeting with a kidney dietitian to find out the amount and type of protein that is right for you, even in the earliest stages of kidney disease. Your healthcare professional will watch your kidney function for any necessary diet or medicine changes.