People with kidney disease typically need to follow a diet low in sodium, protein, potassium, and phosphorus. This means limiting or avoiding foods such as avocados, brown rice, and chips.

The kidneys perform many crucial functions for health, including filtering waste products and excess fluid from the body and removing it through urine. They also regulate the body’s mineral balance and produce a hormone that stimulates red blood cell production.

When a person has kidney disease, waste products can build up in their blood. A doctor may recommend dietary changes to help manage the condition and support kidney function.

This article explains which foods to avoid or limit with kidney disease. It also provides an overview of the renal (or “kidney-friendly”) diet.

A person holding a bunch of grapesShare on Pinterest
Bojan89/Getty Images

A specialist kidney dietitian will typically work with people with kidney disease to tailor a diet to their needs.

A kidney-friendly diet, also called a renal diet, may vary slightly depending on the stage of a person’s kidney disease.

For example, those in the early stages of chronic kidney disease (CKD) should limit their sodium and possibly protein intake.

In the later stages of CKD, known as kidney failure, an individual should follow a diet that limits sodium, potassium, and phosphorus.

A dietitian may ask that individuals following a renal diet avoid the following foods:

Sodium, a main ingredient of salt, is a natural mineral often found in canned foods in high quantities. Manufacturers typically add sodium to canned items to increase shelf life and enhance taste.

With CKD, the kidneys cannot eliminate excess sodium as they should. This means people with CKD should avoid or limit eating canned goods such as soup, vegetables, and beans.

Choosing canned foods labeled “low sodium” and draining the contents can help reduce the amount of sodium a person consumes.

A buildup of phosphorus and potassium can cause problems for people with CKD. Due to the high content of these minerals in whole wheat bread, people with CKD should instead choose white bread.

For example, one slice of whole wheat bread contains 76.3 mg of phosphorus and 90 mg of potassium. White bread, on the other hand, contains 31.6 mg of phosphorus and 32.8 mg of potassium.

If a person does not wish to stop eating whole wheat bread entirely, they could instead consider reducing the amount they eat. For example, they could eat just one slice with a meal rather than two.

Many manufacturers of dark-colored drinks add phosphorus to their products to enhance flavor, prolong shelf life, and prevent discoloration.

Phosphorus in its additive form, found in dark cola and beer, is highly absorbable by the human body and is not recommended for those following a renal diet.

However, root beer is an exception to this as it contains no phosphorus.

While healthcare professionals generally consider avocados a beneficial addition to a person’s diet, people with renal problems may wish to avoid or limit them.

This is because they are high in potassium, with one avocado weighing around 200 g containing 975 mg of potassium. According to the National Kidney Foundation, anything that exceeds 200 mg of potassium per serving is high in potassium.

If needed, a person can still include avocados in their diet, but they should drastically reduce their portion size.

A large banana contains 487 mg of potassium, meaning a person with CKD should avoid or limit eating this fruit. Many other tropical fruits also have high potassium content.

Pineapples may be a suitable alternative as they contain a much smaller amount of potassium compared with other tropical fruits.

Oranges and orange juice are a potassium-rich food and drink.

A small orange contains 174 mg of potassium, while 250 g of orange juice contains as much as 441 mg of potassium.

Alternative fruits that are lower in potassium include grapes, apples, and cranberries.

Dried fruits are concentrated sources of many of the nutrients found in fresh fruits. This means it can be easier to exceed recommended daily intakes from them.

People following a renal diet should avoid apricots, dates, prunes, and raisins, which are all high in potassium.

Tomatoes are another high potassium fruit that a person following a renal diet should limit.

For reference, a cup (245 g) of tomato sauce contains 728 mg of potassium.

While it is nutritious, brown rice has a higher phosphorus and potassium content than white rice.

A cup (155 g) of cooked brown rice contains 149 mg of phosphorus and 94.6 mg of potassium, while a cup (186 g) of cooked white rice contains 68.8 mg of phosphorus and 53.9 mg of potassium.

Bulgur, buckwheat, and couscous are also alternatives to brown rice.

Despite dairy and milk traditionally being promoted for bone health, for people with CKD, consuming too much can be detrimental to bone health. The reason for this is that dairy is a natural source of phosphorus and potassium.

A cup (244 g) of whole milk contains 205 mg of phosphorus and 322 mg of potassium.

Kidney damage can cause an excess of phosphorus to build up in the blood (known as hyperphosphatemia). This condition can cause the body to pull calcium from the bones, resulting in thin, weak bones.

It is important for people following a renal diet to limit dairy products to avoid this buildup of protein waste in the blood.

Coconut milk may be a favorable substitute for people with CKD based on its low potassium, sodium, and oxalate content.

Processed meats are meats that manufacturers have salted, dried, cured, or canned. Some examples include hot dogs, bacon, and pepperoni. To improve their taste and preserve flavor, they often contain lots of salt.

If a person regularly eats highly processed foods, keeping their sodium intake to 2,300 mg per day (the amount recommended by the National Kidney Foundation) may be difficult.

Pickles, processed olives, and relish are all examples of cured or pickled foods.

During the curing or pickling process, manufacturers typically add salt to the food.

For reference, five green pickled olives (considered a small serving) equates to almost 10% of the daily recommended amount of sodium.

Many cereals contain a mixture of potassium, phosphorus, and sodium. A person following a renal diet should avoid all of these.

For example, a 30 g serving of bran flakes contains 160 mg of potassium, 135 mg of phosphorus, and 162 mg of sodium. A 100 g serving of granola contains 539 mg of potassium.

Potatoes, including sweet potatoes, are potassium-rich vegetables.

A medium-sized baked potato contains around 610 mg of potassium, and a medium-sized sweet potato contains 542 mg of potassium.

Leaching is one way a person can reduce the high potassium content in potatoes. This method essentially involves soaking or boiling potatoes in water before cooking, which, according to older research, reduces the original potassium content by at least 50%.

Processed foods include pizza, instant noodles, and convenience meals designed for the microwave. These foods typically contain high levels of salt, sugar, and fat.

As mentioned above, the National Kidney Foundation recommends keeping sodium intake to 2,300 mg per day. This may prove difficult if a person is eating highly processed foods regularly.

Foods such as pretzels, chips, and crackers are typically high in sodium and lacking in nutrients. Because chips come from potatoes, they are also high in potassium.

A small bag of potato chips contains around 148 mg of sodium and 336 mg of potassium, and 60 g of pretzels contain roughly 744 mg of sodium and 134 mg of potassium.

The portion sizes of these snacks can often lead to greater salt intake than intended.

There are many green, leafy vegetables that people following a renal diet may need to avoid or limit due to their high potassium content. This is the case for Swiss chard, spinach, and beet greens.

For example, a cup of raw Swiss chard contains 136 mg of potassium. As with spinach, this vegetable shrinks when boiled, meaning a person may eat more than they would raw. A person with CKD should consider this as it will, in turn, increase their intake of potassium.

Although an individual with CKD must adapt their diet, there are still many suitable options for them to try.

People should choose foods with lower levels of sodium, potassium, and phosphorus. These include:

If an individual has CKD, doctors typically recommend reducing their intake of potassium, phosphorus, and sodium to help manage the condition. The dietary restrictions depend on the stage of the disease.

Although there is a long list of foods that are best to avoid on a renal diet, there is also a wide range of foods that people can eat without affecting their kidney health.

An individual may work with a renal dietitian to find the most suitable diet for them.