CKD Nutrition: How Much Protein is Safe and Beneficial?

How Much Protein is Safe and Beneficial in CKD?

Chronic kidney disease (CKD) is a progressive disorder in which the kidneys lose their ability to filter blood. It is called chronic because the damage happens to the kidneys slowly over a long period. If not properly managed, CKD can lead to kidney failure over time.

1. Introduction

As kidneys cannot filter blood, managing nutrients in appropriate amounts is necessary. Protein management in restricted amounts is another factor in lowering kidney strain. This is because intake of high protein leads to increased intraglomerular pressure and glomerular hyperfiltration. It further damages the glomerular structure, which worsens the complications of CKD.

The protein requirements for CKD patients depend on the severity and stage of the disease. In the early stages of CKD (stages 1 and 2), the patient is recommended to consume protein 0.6-0.8 g/kg of body weight. While in advanced stages of CKD (3-5), the patients should restrict their protein intake to  0.55-0.60 grams/kg of body weight per day.

The main purpose of restricting protein is to effectively manage CKD complications by reducing the load on the kidneys and ensuring the right amount of required nutrition for a healthy lifestyle.

Protein is a necessary macronutrient, but excessive amounts are harmful to kidneys, especially in CKD. The right amount is beneficial for improving health complications and slowing disease progression. 

2. Understanding Protein's Role in Kidney Health

What Is Protein, and Why Is It Important?

Protein is a large, complex molecule of amino acids that plays a major role in the body. It is essential for the structure, function, and regulation of the body's tissues and organs. 

Healthy kidneys play a major role in protein metabolism by filtering urea and other waste products from the blood, which are then excreted in urine. 

Glomerular filtration is when kidneys filter blood by removing waste and excess fluids while keeping essential substances like protein and other nutrients. This filtration occurs in tiny structures of nephrons called glomeruli, which act as small filters. 

Similarly, glomerular filtration rate (GFR) is a measure to indicate how well the kidneys are functioning. A GFR value of 90 or higher indicates normal functioning of the kidneys. However, a glomerular filtration rate (GFR) of less than 60 for three or more months indicates chronic kidney disease (CKD).

How Kidneys Process Protein?

When protein is consumed, it is broken down in the body, producing nitrogenous waste that the kidneys must filter out. In CKD, the kidneys are already compromised and cannot effectively remove the waste products.

The National Institute of Health (NIH) reported that high dietary protein intake causes intraglomerular hypertension resulting in kidney hyperfiltration, proteinuria and glomerular injury. The NIH also shares that long-term high protein intake stresses the kidneys and links to the development or worsening of chronic kidney disease (CKD), especially in individuals at risk or with compromised kidney function.

3. Recommended Protein Intake for CKD Patients

Protein Guidelines by CKD Stage (Non-Dialysis vs. Dialysis).

According to KDIGO, the recommended protein guidelines for CKD stages with dialysis or without dialysis are as follows:

CKD Stage	GFR Values (mL/min/1.73 m²)	Protein Intake (Non-Dialysis)
CKD Stage 1	≥90 (with kidney damage)	0.8–1.0 g/kg/day
CKD Stage 2	60–89	0.8–1.0 g/kg/day
CKD Stage 3a	45–59	0.6–0.8 g/kg/day
CKD Stage 3b	30–44	0.6–0.8 g/kg/day
CKD Stage 4	15–29	0.6–0.8 g/kg/day
CKD Stage 5 (ESRD)	<15	0.6–0.8 g/kg/day

Dialysis causes significant loss of amino acids and proteins from the blood in dialysis patients. 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. 

In dialysis (hemodialysis and peritoneal dialysis) and advanced stages of CKD, the protein requirement increases to 1.0–1.2 g/kg/day depending on the type of dialysis. A higher protein intake is recommended in peritoneal dialysis patients (1.2–1.4 g/kg) due to increased protein losses. This is because, dialysis increases protein breakdown (catabolism), requires more protein to maintain muscle mass, support tissue repair, and prevent protein-energy wasting (PEW).

It is recommended that people with CKD consult a dietitian. They can help customize a meal plan with required protein intake, fluid restrictions, and other dietary considerations according to their specific condition.

Dietitians also monitor the progress of CKD patients, adjust diet plans, and manage other complications like high potassium or phosphorus levels, which are common in kidney disease. Personalized nutrition strategies help optimize overall health in CKD, improve treatment outcomes, and prevent malnutrition.

Calculating Daily Protein Needs:

The protein requirement can be calculated by tools that are available online. These online tools, such as the NKF Protein Calculator are easily accessible to help patients. Dietitians and healthcare providers also help to calculate protein needs based on individual factors like weight, CKD stage, and treatment type. 

Similarly, Calculator.net is also an easily accessible tool in which the patient can calculate their protein requirements by adding height, weight, age and activity level.  Both calculators can be used as guides to determine the estimated protein requirements. However, the exact requirement of protein intake in CKD should be consulted by a dietitian or health care provider. 

People can also manually calculate protein requirements by multiplying their body weight by 0.8. 

In CKD, the patient is required to limit protein intake in stages 1 and 2 to no more than 0.8 g per kg of their body weight.  For example, the daily protein requirements of a patient with 68kg weight are 68 kg x 0.8 g/kg = 54 g or less. Protein intake should be adjusted based on CKD stage and clinical parameters in advanced stages of CKD. When the GFR values begin to drop in CKD, it is preferable to consume plant-based proteins. These types of proteins are beneficial for CKD and produce less urea than animal protein.

Patients with CKD stages 3-5 (without dialysis) must strictly restrict their protein intake. These patients must limit protein to 0.65g per kg of body weight daily. For example, if the patient weighs 150 lbs or 68 kg, the protein requirements are 68 x 0.6 – 0.8 g/kg = 40-54 grams daily. This equals about 4-6 ounces of protein from animal or plant sources daily.

In dialysis, a patient with 70 kg would need around 70–84 grams of protein per day (70 kg × 1.0–1.2 g).

Clinical guidelines and multiple authentic sources support these stage-specific protein recommendations. Websites such as the National Kidney Foundation (NKF) and Kidney Disease: Improving Global Outcomes (KDIGO) provide a detailed version of high protein complications in CKD. The evidence highlights the importance of carefully managing protein intake to reduce the risk of disease progression and support overall health in CKD patients.

4. Types of Protein: Beneficial vs. Harmful

There are two types of protein, animal-based and plant-based. Animal proteins are rich in essential amino acids but acidic and high in phosphorus. Plant proteins are less acidic and contain lower phosphate levels, making them preferable for CKD management.

Plant-based proteins are considered beneficial, especially for CKD patients, while animal-based proteins are harmful due to acidic load and contribute to metabolic acidosis. Plant proteins are preferable due to their lower phosphate content and less acidic nature. However, plant-based proteins, such as beans and lentils, also contain high amounts of potassium and phosphorus that need to be strictly monitored, especially in CKD patients. Here is a table summarizing the type of protein and its effect on CKD.

 

Protein Type	Plant-Based Proteins	Animal-Based Proteins
Sources	Lentils, beans, tofu, quinoa	Eggs, chicken, beef, fish
Benefits for CKD	Less acidic, has lower phosphate levels, high in fiber, and is beneficial for heart health.	Provides essential amino acids but may require phosphate binders or limit due to high phosphorus content.
Effects on CKD	Lower phosphorus and acid load reduces kidney stress and helps maintain acid-base balance.	Higher in phosphate and acidic load, which increases the risk of kidney damage.
Sample Meals	Tofu stir-fry, lentil soup, quinoa salad	Egg white omelet with veggies, grilled fish with lemon

The National Kidney Foundation (NKF) highlighted the findings of its research that concluded that the participants with the highest adherence to overall plant-based diets and healthy plant-based diets had a 26% and 21% lower risk of all-cause mortality in CKD patients.

5. High-Protein Diets and Renal Function

Risks of Excessive Protein Intake:

High protein intake is harmful, especially for chronic kidney disease patients. Consuming a lot of protein in the diet causes the afferent arteriole to dilate and raises GFR, which may cause glomerular hyperfiltration, stress the kidney and result in kidney injury.

Kidneys under protein overload are like overworked water filters. As protein is broken down (protein catabolism) in the body, it creates waste products like urea and other products, which need to be excreted by the kidneys. In cases of high-protein intake, this can lead to uremia, where the waste builds up in the blood. It increases pressure on the renal system, also termed glomerular hyperfiltration. Over time, this can contribute to electrolyte imbalances and increase the risk of conditions such as chronic kidney disease (CKD).

A recent study published in PubMed highlighted that the consumption of a diet rich in high protein increases eGFR values in healthy individuals. Similarly, the long-term consumption of a high-protein diet leads to kidney disease and other kidney-related complications.

6. Practical Tips for Managing Protein Consumption

For CKD patients, reducing protein intake lowers the stress on kidneys and prevents the buildup of waste products like urea in the bloodstream. A 2018 review of 18 studies reported that a diet low in protein effectively slows the progression of renal failure. Here are some tips for consuming low-protein foods in CKD.

• Consume unsweetened rice or low-protein milk as a substitute for dairy milk.
• Bulk up soups with a small amount of pasta or rice
• Increase vegetables in the diet while lowering meat consumption. For example, diced mushrooms are a better substitute for spaghetti than meat in CKD patients.
• For a low-protein diet, patient with CKD can also add a small amount of egg in their saad to make them more filling.
• Parmesan cheese can also be added to top meals to enhance the flavor without adding too much protein. 
• Choose healthy fats in a meal to make it more filling.
• Make sandwiches with lots of lettuce, cucumber, chopped celery, apple, parsley, or water chestnuts.
• Use unsalted meats sliced very thin; spreading them out to look like a larger portion.
• Use whole grain bread that is more thinly sliced or lower in protein.
• Use vegetables and grains as the main dish and meats or other high-value protein as the side dish
• Stir fry dishes and fajitas are a great way to combine vegetables with small pieces of meat or chicken
• Try grilling kebabs, using smaller pieces of meat and more vegetables or fruits. Mix small pieces of meat, ground meat, or chicken with rice or pasta.
• Toss with a chef salad with lettuce and crisp vegetables adding smaller strips of meat and egg.
• For casseroles, use less meat than the recipe calls for and increase starches (rice or pasta) and vegetables –use reduced-sodium or homemade soups or broths in your casserole recipes. 
• Allow yourself extra portions or larger servings of whole-grain bread, rolls, pasta, rice, fruits, and vegetables to help meet your caloric needs without eating more protein.
  
  

How to Measure Portion Size Accurately?

Portion size is essential to maintaining food portions that reduce overeating, especially in CKD. Here are some tips to measure and control portion size accurately.

• Use smaller plates, bowels, or dinnerware (dishes smaller in size and shape to lower the consumption of food)
• Make a plate as a portion guide (promote balanced eating and weight loss)
• Use the hand-serving guides for high-protein foods. For example, a palm-sized serving for women and two palm-sized portions for men is generally recommended.
• Ask for a half portion while dining out.
• Take a glass of water before a meal (taking a glass before 30 minutes is a natural way to aid portion control).
• Consume food slowly to reduce total intake.
• Don't eat food straight from the jumbo-size food packages to avoid overeating
• Maintain a food diary that is beneficial for mindful eating by writing down all consumed food and drinks.
• Be aware of the suitable serving size of food you consume and read labels before consuming packaged food items. For example, the portion sizes of some foods are

• Cooked pasta or rice: 1/2 cup (75 and 100 grams)
• Vegetables and salad: 1–2 cups (150–300 grams)
• Breakfast cereal: 1 cup (40 grams)
• Cooked beans: 1/2 cup (90 grams)
• Nut butter: 2 tablespoons (16 grams)
• Cooked meats: 3 ounces (85 grams)

 

You can also check a handy guide to Chronic Kidney Disease (CKD) portion sizes.

Planning Meals for CKD:

Here are some low-protein ideas for meals and snacks beneficial for CKD patients.

 

Low Protein Meal	Low Protein Snacks
Sandwich with very thinly sliced meat and lots of vegetables, such as cucumber and lettuce Rice in low protein with vegetables and a small portion of meat, tofu, or shellfish Low-protein pasta with tomato paste and roasted vegetables Burrito meal made with a low-protein tortilla, vegetables, salsa, and homemade guacamole Low-protein rice with vegetable curry Homemade vegetable soup	Fresh fruit like apple, banana, berries Raw vegetable sticks with salsa or homemade guacamole Homemade muffins, made with a low-protein baking mix Any fruit smoothie made with water or a low-protein dairy alternative, such as rice milk Homemade fruit juice popsicles

 

Similarly, here is an example of Festive Turkey Salad and Chicken Pasta with the original and modified recipe with lower protein content for CKD patients.

 

Festive Turkey Salad
Original Recipe	Modified Recipe (with substitution)
3 cups chopped cooked turkey breast without skin 1/4 cup diced celery 1 cup raw red delicious apples with skin 1/4 cup coarsely chopped pecans 3 tbs. low-calorie mayonnaise (Cranberry French Dressing) 1/4 cup jellied cranberry sauce with 1/8 tsp. Salt 1/8 tsp. Paprika 1/8 tsp. dry mustard 1/8 tsp. Pepper 1 tbs. Vinegar 2 tbs. vegetable oil Yield: 4 one-cup servings with 2 tbs. dressing on each serving	1 1/2 cups chopped cooked turkey breast without skin 1 cup diced celery 3 cups raw red delicious apples with skin 1/4 cup coarsely chopped pecans 3 tbs. regular mayonnaise (Cranberry French Dressing) 1/2 cup jellied cranberry sauce 1/8 tsp. Paprika 1/8 tsp. dry mustard 1/8 tsp. Pepper 1 tbs. Vinegar 2 tbs. vegetable oil Yield: 6 one-cup servings with 2 tbs. dressing on each serving

Chicken Pasta Casserole
Original Recipe	Modified Recipe (with substitution)
1 12-oz package egg noodles 1-1/2 lb ground chicken or beef 1 tsp. onion salt 1 tsp. garlic salt Accent to taste 1 tsp. black pepper 1 6-oz can tomato paste 1 4-oz can of mushroom stems and pieces (drained) 1 8-oz container sour cream 1/4 cup cottage cheese 1/2 lb grated cheddar cheese	1 12-oz pkg. regular or low-protein noodles 1/2 lb ground chicken or beef 1 cup diced celery 1 tsp. onion powder 1 tsp. garlic powder 1 tsp. black pepper 1 6-oz can tomato paste 1 4-oz can mushroom stems and pieces (drained and rinsed) 4 oz sour cream 3 tbs. cottage cheese 1/4 lb grated sharp cheddar cheese

Balancing Nutrients: Sodium, Potassium, and Phosphorus.

For CKD patients, it is essential to balance nutrients of sodium, potassium and phosphorus along with adequate protein intake. These patients should monitor these 3 micronutrients; sodium, potassium and phosphorus, while consuming any food. They are advised to consume foods with restricted amounts of these nutrients to avoid complications.

• Sodium intake: In CKD, it is advised to limit sodium intake up to 2000 mg/day because higher amounts can lead to fluid retention, high blood pressure and worsening CKD. Therefore, always read food labels to spot any hidden sodium in processed foods such as frozen items, ketchup and sauces.
• Potassium: High potassium levels also cause complications, especially in CKD, and lead to irregular heartbeat and muscle weakness. If potassium levels are too high in the blood, limit the potassium intake of food items up to 2000 mg/day. The limitations of potassium intake depend on serum potassium levels and not all CKD patients need to restrict their potassium until they suffer from hyperkalemia. Kidney-friendly alternative foods are apples, berries, cabbage, carrots, and green beans.
• Phosphorus: High phosphorus levels cause bone disorders and calcium deposition in blood vessels. These high levels are dangerous, so it is advised that CKD patients limit their phosphorus intake to 800-1000mg/day. The recommended amount may differ based on the stage of CKD and dialysis status, with those on dialysis sometimes needing a stricter phosphorus limit. To manage phosphorus levels in the blood, take phosphorus binders if prescribed and consume foods that are low in phosphorus.

7. FAQs About Protein Intake and CKD

How much protein is safe for kidneys?

For patients with CKD, the recommended protein intake usually ranges from 0.6 to 0.8 grams per kilogram of body weight per day. However, the actual requirements should be customized according to individual needs, depending on the stage of CKD, activity level, and other health conditions.

What is the best protein for CKD patients?

The best protein sources for CKD patients are high-quality proteins that provide essential amino acids and produce less waste. These include:

• Egg whites
• Fish
• Chicken (without skin)
• Plant-based proteins such as soy, legumes, and quinoa (in moderation, as some plant-based proteins contain phosphorus and potassium, which may need monitoring).

Why does a high-protein diet increase GFR?

A high-protein diet increases the glomerular filtration rate (GFR) temporarily, because it leads to a higher demand for the kidneys to filter out the byproducts of protein metabolism. This increased workload can initially result in a higher GFR, but over time, excessive protein intake may worsen kidney function by increasing the strain on already compromised kidneys.

How much protein is in urine for CKD?

In CKD patients, normal protein excretion should be less than 150 mg/day. Higher protein levels in the urine indicate kidney damage, with more than 3.5 grams of protein in urine daily as a sign of severe proteinuria, a common complication of advanced CKD.

What is the safest protein for CKD?

The safest protein sources for CKD are plant-based proteins such as egg whites and soy protein due to their lower phosphorus content compared to animal proteins. Other safest protein sources also includes Greek yogurt, high-protein smoothies, meat substitutes, nutrition drinks, protein bars, protein powder, liquid protein supplements and tofu.

Can CKD patients eat dairy products for protein?

Dairy products are a source of high-quality protein, but they are also high in phosphorus and potassium, which can be risky for CKD patients. Therefore, it is important to consume dairy products in moderation and choose lower-phosphorus options, such as low-potassium milk or plant-based milk alternatives.

Can CKD patients follow a high-protein diet for weight loss or muscle gain?

Doctors do not recommend a high-protein diet for CKD patients, as it can worsen renal function. Patients should balance weight loss and muscle gain with a proper diet that aligns with kidney health, focusing on moderate protein intake, as instructed by a dietitian.

What happens if CKD patients eat too much protein?

Excess protein can strain the kidneys in CKD patients, leading to increased waste buildup (like urea), worsening proteinuria (protein in urine), and higher phosphorus levels. Excess protein can also raise GFR, accelerating kidney damage. Over time, this worsens kidney function, potentially causing fluid retention, metabolic acidosis, and other complications.

Can I eat red meat with CKD?

No, people with chronic kidney disease (CKD) should limit their red meat intake to increase the production of uremic toxins in the gut, which can increase the risk of cardiovascular mortality.

8. Conclusion

Protein is an essential macronutrient necessary for the body to perform various functions. In chronic kidney disease, protein management is crucial due to damaged kidneys. The patient should not consume protein more than 0.8g per kg of body weight. It is also recommended for CKD patients to consume protein from plant-based sources such as lentils, beans, chicken, egg whites, and fish to lower kidney stress. Patients can also track their protein intake by food diary or nutrition app to ensure you're not exceeding recommended limits.

Therefore, always consult a dietitian or healthcare provider for customized meal plans depending on your stage of CKD and health conditions. In CKD, regularly monitoring kidney function, GFR, and protein in urine is necessary to adjust dietary intake over time.