Living With Kidney Disease? Know Renal Diet Basics

If you're among the 1 in 7 adults in the U.S. who have been diagnosed with chronic kidney disease, you may be wondering how to adjust your diet to protect your kidneys and slow the progression of the disease. A renal diet, also known as a kidney-friendly diet, can help you do just that.

By avoiding certain foods and focusing on others, you can give your kidneys the support they need to stay healthy and function as well as possible.

In this article, we'll cover the basics of a renal diet and provide tips for choosing the best kidney-healthy foods. Whether you're a seasoned home cook or a novice in the kitchen, you'll find practical advice to help you create delicious and nutritious meals that support your kidney health while living with chronic kidney disease.

What Is A Healthy Kidney Diet?

A kidney-friendly diet, also known as a renal diet, can help to ease the workload on the kidneys and slow the progression of kidney disease.

People living with kidney disease need to limit their intake of certain nutrients, including sodium, phosphorus and potassium. This is because the kidneys play a critical role in filtering these minerals from the blood, and when the kidneys aren't working right, they can accumulate in the body and cause health complications.

A healthy diet for a person living with kidney disease depends on how severe and what stage the disease is, as well as other factors like a person’s age, sex and other medical conditions they live with. However, these 5 general guidelines can help most people needing a kidney-friendly diet:

1. Limit sodium intake

High levels of sodium can raise blood pressure and further kidney damage.

“You want to reduce your salt and your protein intake so that we're not putting extra stress on our kidneys that doesn't need to be there,” said Caitlin Sienkiewicz, DO, who specializes in occupational and family medicine at Franciscan Physician Network.

On a kidney-friendly diet, you’ll limit your intake of processed and packaged foods, canned soups and vegetables, and salty snacks, and instead choose fresh, whole foods that are naturally low in sodium.

2. Reduce protein intake

Eating too much protein can put stress on the kidneys, especially if they are already damaged. A diet that is lower in protein may be recommended.

“Protein is important for building muscle and repairing tissues in your body, but eating some types of protein can be hard on your kidneys,” said Kate Velazquez, clinical dietitian at Franciscan Health Indianapolis. “Rather than eating a lot of red meat or processed meats, focus on lean protein sources like chicken, fish and plant-based proteins.”

3. Choose healthy fats

Saturated and trans fats can increase the risk of heart disease, which is a common complication of kidney disease. Instead, choose healthy fats like monounsaturated and polyunsaturated fats found in foods like avocado, nuts, seeds and olive oil.

4. Eat more fruits and vegetables

Fruits and vegetables are high in vitamins, minerals and fiber, and are generally low in sodium and protein, making them an excellent choice for a kidney-friendly diet. Fruits and vegetables can help to improve overall health and reduce the risk of complications related to kidney disease.

5. Watch potassium and phosphorus intake

Some people living with chronic kidney disease may need to limit foods that are high in potassium and phosphorus, such as bananas, oranges, potatoes, dairy products and nuts. A registered dietitian can help to create a meal plan that takes these factors into account.

A kidney-friendly diet should be tailored to each person's needs and dietary preferences by a healthcare professional or registered dietitian who understands chronic kidney disease. They can help you create a healthy meal plan that supports your kidney health while still meeting your nutritional needs.

What Foods Are Kidney-Friendly?

“At first, the idea of going on a renal diet to protect your kidneys may seem overwhelming, but many foods are in fact, kidney-friendly,” Velazquez said.

Here are some examples of kidney-healthy foods from each food group:

Kidney-Friendly Proteins

• Lean meats, such as chicken and turkey without the skin
• Fish, such as salmon, tuna and herring
• Low-fat dairy products, such as skim milk, yogurt and cheese
• Eggs
• Plant-based protein sources, such as beans, lentils and tofu

Fruits

• Apples
• Berries
• Cherries
• Grapes
• Pineapple
• Watermelon

Vegetables

• Bell peppers
• Broccoli
• Carrots
• Cauliflower
• Cabbage
• Eggplant
• Garlic
• Onions
• Spinach

Grains

• Whole-grain breads and cereals
• Brown rice
• Quinoa
• Whole-grain pasta

Fats

• Olive oil
• Canola oil
• Avocado

Beverages

• Water
• Herbal teas
• Low-sugar fruit juices

What Foods Should I Avoid On A Renal Diet?

If you are eating a renal diet, consider avoiding or limiting these foods:

Processed foods

Processed foods tend to be high in sodium and phosphorus, so it is best to avoid them whenever possible.

Certain herbs, seasonings and salts

Some herbs, seasonings, and salts can contain high levels of sodium and phosphorus. It is best to read labels and choose low-sodium options.

Excess fluids

Limiting fluids is often recommended for many people with kidney disease because the kidneys are responsible for removing excess fluids from the body. In kidney disease, the kidneys may not function properly, leading to a buildup of fluid in the body. This can cause various complications such as edema (swelling), high blood pressure, and heart failure.

If you have chronic kidney disease, depending on your stage and other health conditions, your doctor may tell you to limit your fluids to 6 cups a day or less. By limiting fluids, you can help prevent fluid buildup and manage these complications.

Why Should Proteins Be Limited On A Renal Diet?

The more protein you eat, the more nitrogen waste products your kidneys have to filter out, and this adds to the strain on your kidneys. People with kidney disease may need to limit protein intake, depending on the severity of the CKD.

Work with a healthcare professional or registered dietitian to determine the appropriate level of protein intake.

Why Is Salt Limited With Kidney Disease?

Regardless of whether you have chronic kidney disease, consuming excessive amounts of salt can have negative effects on kidney health. The kidneys play a crucial role in regulating the body's sodium balance Consuming too much salt in foods and beverages can increase blood pressure and put additional strain on the kidneys, potentially leading to kidney damage over time.

When you consume salt, your body tries to maintain a balance of sodium and water. To do this, the kidneys filter excess sodium out of the blood and excrete it in the urine. However, if you consume too much salt, your kidneys may struggle to keep up with the amount of sodium that needs to be filtered. This can lead to an increase in blood pressure and cause damage to the small blood vessels in the kidneys.

While the recommended sodium intake for most people is no more than 2,300 milligrams per day, if you have chronic kidney disease or medical conditions such as high blood pressure or diabetes, your healthcare provider may recommend you consumer even less each day to help protect your kidneys. Many people on renal diets are limited to less than 1,500 mg of sodium daily. Work with your healthcare provider to determine safe amounts of daily sodium for you, based on your renal health.

Why Is Potassium Limited On A Renal Diet?

In some cases, people with kidney disease may be advised to limit their intake of high-potassium foods. When the kidneys don’t work correctly, they may have trouble filtering excess potassium from the blood. This can lead to a buildup of potassium in the body, which can be dangerous and even life-threatening. Extra potassium can cause nausea, diarrhea, breathing problems and heart problems.

Typically, people with kidney disease should limit their potassium intake to under 3,000 mg per day.

Foods that are high in potassium include bananas, oranges, potatoes, spinach, tomatoes, avocados, beans, lentils, and yogurt.

Why Is Phosphorus Harmful With Kidney Disease?

While phosphorus is an essential nutrient that plays a critical role in bone and cell health, too much of it can be harmful to people with kidney disease.

Like with potassium and sodium, when the kidneys are not functioning correctly, phosphorus can build up in your body. High levels of phosphorus in the blood can lead to bone pain, brittle bones, skin ulcers and heart damage.

To protect the kidneys, people with kidney problems are often advised to limit their intake of foods high in phosphorus. This is especially true for people on dialysis or with later stages of kidney disease.

Foods that are high in phosphorus include dairy products, meat, fish, poultry, beans, nuts, and whole grains.

What Are Safer Cooking Methods For Kidney-Friendly Diets?

Cooking at home allows you to have more control over kidney-friendly ingredients and preparation methods. When it comes to cooking methods for people with kidney disease, it's important to consider the levels of potassium, sodium, and phosphorus in the foods being prepared. Here are some cooking methods that are generally considered safe for people with kidney disease, as well as some that are less safe:

Best cooking methods for people with kidney disease:

Cooking methods that minimize use of potassium, sodium or phosphorus in foods include:

Boiling

Boiling is a safe cooking method for people with kidney disease because it removes a significant amount of potassium and phosphorus from the food. However, it's important not to add salt to the boiling water as this can increase sodium levels.

Steaming

Steaming is another safe cooking method for people with kidney disease as it doesn't require the use of salt or oil, which can increase sodium and fat levels. Steaming also helps to retain the nutrients in the food.

Baking

Baking is a safe cooking method for people with kidney disease as long as low-phosphorus ingredients are used. For example, you can use egg whites instead of whole eggs and substitute low-phosphorus flours for regular flour.

Less safe cooking methods for people with kidney disease:

Grilling

Grilling can be problematic for people with kidney disease because it can cause the formation of advanced glycation end products (AGEs) in the food. These AGEs have been linked to inflammation and oxidative stress in the body. Grilling can also cause the food to become charred, which can increase the risk of cancer.

Frying

Frying is a less safe cooking method for people with kidney disease because it often requires the use of large amounts oil, which can increase fat levels. Additionally, fried foods are often high in sodium.

Braising

Braising is a less safe cooking method for people with kidney disease because it involves cooking the food in a liquid, which can increase sodium levels. If you do choose to braise your food, it's important to use low-sodium broth or water.

Cooking when you live with kidney disease can be challenging, but with some careful planning and adjustments, it's possible to enjoy a wide variety of delicious and nutritious meals.