Around 13% of the world’s population is estimated to have chronic kidney disease.
If kidney disease progresses, it can cause irreversible kidney damage requiring long-term dialysis.
If you have kidney disease, you’re probably wondering what you can do to preserve your kidney function.
A renal diet is one way to help you preserve your kidney health and function while supporting your overall health.
What is a renal diet?
A renal diet aims to help people with kidney disease or other kidney problems stay as healthy as they can. A renal diet is low in sodium, moderate to low in protein, and limited in potassium and phosphorus.
When your kidneys aren’t working as well as they should, they can have difficulty filtering out minerals like potassium and phosphorus. If you eat too much potassium or phosphorus, your blood levels of those minerals can become high, which can be dangerous.
A renal diet is low in sodium. Sodium causes your body to hold on to more fluids, thus increasing your blood pressure.
When your blood pressure and fluid levels are high, your kidneys have to work harder to filter the excess fluid and can become damaged even more. High sodium diets can raise your blood pressure, which also worsens kidney health.
Eating protein leads to waste byproducts in your blood. If your kidney function has declined, these waste byproducts can’t effectively be filtered out of your blood.
If you eat too much protein, it can cause high blood pressure within your kidneys and damage your kidneys. (1)
Who is a renal diet for?
Some signs that you may need to follow a renal diet include high potassium levels, high phosphorus levels, and elevated markers of kidney function such as BUN and creatinine. Your healthcare team, especially your nephrologist, can help you determine how strict you need to be with your renal diet.
A renal diet is typically recommended if you have chronic kidney disease. If you have early-stage kidney disease (stages one through two and possibly three), you might not need to follow all aspects of a renal diet.
If you have more advanced stages of kidney disease, such as stages four through five, you likely need to follow a stricter renal diet. You should ask your healthcare provider if you need to be on a renal diet if you’re unsure.
A renal diet is very important if you have end-stage kidney disease (stage five) and are on dialysis. However, your protein needs are increased on dialysis, so you should eat high-quality protein throughout the day to help support your body’s needs.
A renal dietitian can help you gain a better understanding of how much protein you need on dialysis. Eating too little protein on dialysis can lead to protein malnutrition.
You might also need to temporarily follow a renal diet if you’ve suffered an acute kidney injury that can cause short-term kidney damage.
Regardless of your stage of kidney disease, following a low-sodium diet is always recommended since kidney damage can impair your body’s ability to regulate your blood pressure.
What can you eat on a renal diet?
A renal diet should be balanced and include foods from different food groups to be healthy. You might not need to limit potassium or phosphorus if your blood levels of those minerals are normal or if you don’t have advanced kidney disease.
Some foods to eat on a renal diet include:
Lower-potassium fruits & vegetables
Remember that eating a lot of low-potassium foods can make it similar to a smaller portion of a high-potassium food.
Portion size is the most important aspect of eating these foods. If you want to eat a higher potassium food, be careful to avoid other high-potassium foods throughout the rest of the day.
- Fruit cocktail
- Grapes and grape juice
- Mandarin oranges
- Alfalfa sprouts
- Asparagus (6 raw spears)
- Broccoli (raw or cooked from frozen – cooked broccoli is higher in potassium)
- Carrots (cooked)
- Celery (1 stalk)
- Corn (half an ear if it’s on the cob)
- Green beans or wax beans
- White mushrooms (raw)
- Peas (green)
- Water chestnuts
Remember that eating a lot of low-phosphorus foods can make it similar to a smaller portion of a high-phosphorus food.
Portion size is the most important aspect of eating these foods. If you want to eat a higher phosphorus food, be careful to avoid other high-phosphorus foods throughout the rest of the day.
- Fresh fruits and vegetables
- Rice milk, unenriched
- White bread (not whole grain)
- Meat, poultry, and fish
- Corn and rice cereals
- Soda without phosphate additives
- Home-brewed iced tea
- Any fresh or frozen beef, lamb, pork, poultry, and fish
- Eggs and egg substitutes
- Low-sodium peanut butter
- Dry peas and beans (not canned)
- Low-sodium canned fish
- Drained, water, or oil-packed canned fish or poultry
- Milk, yogurt, ice cream, and ice milk
- Low-sodium cheeses, cream cheese, ricotta cheese, and mozzarella
- Bread, bagels, and rolls without salted tops
- Muffins and ready-to-eat cereals
- All rice and pasta – avoid adding salt
- Low-sodium corn and flour tortillas and noodles
- Low-sodium crackers and breadsticks
- Unsalted popcorn, chips, and pretzels
- Fresh and frozen vegetables without sauces
- Low-sodium canned vegetables, sauces, and juices
- Fresh potatoes, frozen French fries, and instant mashed potatoes
- Fresh, frozen, and canned fruit
- Dried fruits
If you’re on dialysis, your protein needs may be increased. If you’re not on dialysis and have kidney disease, it’s important not to overeat protein since its waste byproducts can’t be filtered out of your blood as easily by your kidneys.
According to studies, it’s important not to under-eat protein either since this may cause a decline in kidney function.
A good rule of thumb to follow is to aim for 0.8 grams of protein per kilogram of your body weight per day. For a 150-pound (68 kilograms) person, that would be around 54 grams of protein per day.
Some examples of high-quality protein include:
- Chicken or turkey
- Lean red meat like pork chops
- Greek yogurt (if your potassium and phosphorus levels aren’t high)
- Cottage cheese (watch the portion size since it’s high in sodium)
- Protein bars and powders
What foods should you not eat on a renal diet?
If your blood levels of potassium and/or phosphorus are too high, you should limit your intake of foods high in those minerals.
You might only need to limit one and not both depending on your unique situation, so you should check with your healthcare provider before overly-limiting potassium or phosphorus.
- Dried fruit
- Honeydew melon
- Oranges and orange juice
- Pomegranate and pomegranate juice
- Prunes and prune juice
- Acorn squash, butternut squash, Hubbard squash
- Baked beans, black beans, refried beans
- Broccoli (cooked)
- Brussels sprouts
- Onions (fried)
- Spinach (cooked)
- Tomatoes, tomato sauce, and tomato paste
- Vegetable juice
- Bran products
- Creamed soups
- French fries
- Ice cream
- Milk (buttermilk, chocolate, eggnog evaporated, malted, soy and milkshakes)
- Peanut butter
- Potato chips
- Salt substitutes
- Dairy foods
- Bran cereals and whole-grain products that include the bran
- Colas and other drinks with phosphate additives
- Some bottled iced tea
Regardless of your kidney disease stage, you should limit your sodium intake. Aim to keep your sodium intake below 2,000 milligrams per day or less if your healthcare provider recommends it.
Sodium is found in processed foods like frozen ready-to-eat meals, quick bread mixes, canned soups, and snack foods like chips, pretzels, etc.
Some examples of high-sodium foods include:
- Smoked, cured, or canned meats – this includes bacon, deli meat, sausage, sardines, anchovies, etc.
- Frozen dinners like burritos, pizzas, and other “TV dinners”
- Canned meals like chili, soups, “Spaghetti-O’s”, etc.
- Canned beans and vegetables with salt added
- Salty snacks like chips, microwave popcorn, pretzels, etc.
- Quick-bread mixes like pancakes, muffins, etc. due to the baking soda
What are the benefits of a renal diet?
A renal diet helps your kidneys not work as hard and can help preserve their function. By limiting high-sodium foods, your kidneys aren’t stressed by higher blood pressure and unbalanced fluid levels.
Eating low or moderate amounts of potassium, phosphorus, and protein helps prevent excess levels of minerals or waste byproducts from accumulating in your bloodstream.
If your blood levels of phosphorus are too high, it can cause your body to pull calcium from your bones, which weakens them and may increase your risk of getting bone fractures. Prolonged periods of having high phosphorus levels can increase your risk of heart attack and stroke.
High potassium levels can damage your heart and may even cause a heart attack.
Are there any risks of a renal diet?
A renal diet can be restrictive and can lead to nutrient deficiencies if it isn’t well-planned and balanced. Working with a renal registered dietitian and knowing your blood levels of potassium and phosphorus can help prevent nutrient deficiencies.
For instance, if you’re in an early stage of kidney disease and have normal potassium levels, you’ll miss out on the benefits of high-potassium foods, such as their ability to help lower your blood pressure.
Avoiding whole grains or dairy products if your phosphorus levels are normal can lead to inadequate fiber and calcium intake.
Some symptoms of low potassium levels include:
- Muscle twitches
- Muscle cramps or weakness
- Abnormal heart rhythm
- Kidney problems
Symptoms of low phosphorus levels include:
- Muscle weakness
- Softening or weakening of bones
- Depletion of muscles
- Altered mental state
- Heart failure
- Muscle pain
Not eating enough protein can lead to muscle and weight loss, hunger, and decreased skin integrity. That’s why a renal diet should be considered a moderate protein diet, not a low-protein diet.
If you’re on dialysis and don’t eat enough protein, your albumin levels may drop too low. Low albumin levels can be indicative of poor nutritional status.
How can I repair my kidneys naturally?
According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), there are ways to help prevent kidney disease.
Here are a few easy ways to promote your kidney health:
- Avoid high-sodium foods
- Be physically active regularly
- Limit alcohol intake
- Aim to be at a healthy weight
- Manage your blood sugar levels if you have prediabetes or diabetes
- Don’t smoke
- Get enough sleep
- Manage your stress levels
- Have regular physicals and blood work to assess your overall health
A renal diet is designed to prevent further damage to your kidneys. A renal diet is recommended if you have kidney disease. However, you might not need to follow all aspects of a renal diet if your blood levels of certain minerals are normal or if you have very early-stage kidney disease.
A strict renal diet is low in sodium, phosphorus, and potassium and is moderate in protein.
If it isn’t necessary, following a strict renal diet can lead to nutrient deficiencies and can cause distress since it can be difficult to navigate food choices. Work with your healthcare provider to better understand what aspects of a renal diet you should be following.