Someone with kidney disease may have a buildup of waste products in their blood. A doctor may recommend that individuals change what they eat to help manage the condition and support kidney function.
The kidneys are a pair of essential organs situated on either side of the spine at the bottom of the rib cage.
They perform many crucial functions for health, including filtering waste products and excess fluid from the body and removing it through urine.
The kidneys also play a critical role in regulating the body’s mineral balance, and they produce a hormone that stimulates red blood cell production.
Kidney disease means that the kidneys are damaged and do not function properly. Poorly controlled diabetes can also lead to end-stage kidney disease.
Other common risk factors include age, high blood pressure, heart disease, alcohol use disorder, and carrying the hepatitis C virus.
A recent study also found that African American people are about five times more likely to develop end-stage kidney disease than white people.
When a person has kidney disease, they may have excess waste products in their blood. A doctor may suggest a change in diet to help manage the condition and support kidney function.
This article looks at which foods to avoid or limit with kidney disease. It also provides an overview of the renal, or kidney-friendly, diet.
Typically, a specialist kidney dietitian will work with people with kidney disease to tailor a diet to their needs.
A kidney-friendly diet, also called a renal diet, is low in sodium, phosphorus, and protein. Some individuals may need to limit their potassium, calcium, and potentially fluid intake, depending on the stage of kidney disease they have.
Those in the early stages of chronic kidney disease (CKD) will likely avoid or limit different foods than people with end-stage renal disease (ESRD), also called kidney failure.
Early Stages of CKD
People in the early stages of chronic kidney disease must limit their sodium and possibly protein intake.
Sodium is a major component of table salt, but it is also found in many other foods, specially preserved and pre-packaged foods. So always check packaging to determine the levels of sodium in a product.
A dietitian may recommend the Dietary Approaches to Stop Hypertension (DASH) diet, which helps decrease blood pressure. This may help lower a person’s risk of heart disease and kidney stone formation.
Healthcare professionals recognize the DASH diet as a treatment for high blood pressure, heart disease, and CKD.
The DASH diet limits daily sodium intake to 2,300 milligrams (mg) at most, and protein intake to 18% of a person’s total calories.
People on dialysis should not follow this diet.
Later Stages of CKD
If an individual’s kidney disease progresses, the kidneys cannot filter the blood as effectively. They may not remove enough excess sodium, potassium, and phosphorus, leading to the accumulation of these nutrients in the blood.
In the later stages of CKD, an individual must follow a diet that limits the buildup of these materials. Therefore, they may also need to restrict their intake of potassium or phosphorus.
In general, eating a lot of protein can aggravate CKD because it creates more work for the kidneys. For this reason, doctors may recommend that people with CKD limit their intake of protein.
However, people with end-stage renal disease (ESRD) may need dialysis treatments to filter their blood. Dialysis removes protein metabolites from the blood.
This means that individuals undergoing regular dialysis treatments may actually need to increase their protein intake to make up for the protein they have lost through dialysis.
It is important to highlight that this approach is the opposite of that in early-stage CKD, in which people often limit their protein intake.
The amount of protein someone needs depends on their body size, nutritional status, and how well the kidneys function. A kidney dietitian can recommend the right protein intake for a person with CKD.
Dialysis treatments also remove toxins, minerals, and excess fluid from the blood.
Doctors may need to regularly monitor an individual’s sodium, potassium, phosphorus, and protein levels to ensure their diet matches their health needs and the blood is healthy.
Foods to Avoid
A dietitian may ask that individuals on a renal diet to avoid specific foods.
Sodium, a main ingredient of salt, is a natural mineral found in many foods and table salt.
People with kidney problems may find sodium and fluid build up in their body, leading to swollen ankles, increased blood pressure, shortness of breath, and potentially fluid around the heart and lungs.
The National Kidney Foundation recommends healthy people consume no more than 2,300 mg of sodium per day. People should limit their intake of salted snacks, cured meats, and processed foods.
Processed foods include pizza, instant noodles, and convenience meals designed for the microwave. These foods typically contain high levels of salt, sugar, and fat.
Potassium is another mineral in foods. Healthy kidneys balance the blood’s potassium levels, but those with CKD may need to limit their intake.
A person with CKD may want to restrict their dietary potassium to under 2,000 mg per day.
In this case, they should avoid the following high-potassium foods:
- dried apricots
- bran and granola
- lentils and beans, including canned baked beans
- milk and yogurt
- nuts and seeds
- peanut butter
- salt substitutes
Phosphorus is a mineral found in the bones. The body needs it to stay healthy, but it can cause damage at high levels.
Most people should limit their phosphorus intake to 700 mg per day.
To reduce phosphorus intake, avoid the following foods:
- any bottled beverage that has phosphate as an additive
- beer and dark colas
- chocolate candy and caramels
- chocolate drinks
- dairy products, such as cheese, milk, ice cream, yogurt, and creamy soups that contain dairy
- organ meats
- oysters, sardines, and fish roe
- processed foods, such as pizza, hot dogs, bacon, and sausage
- whole grain bread and bran cereals
Fruits and vegetables
Although fruits and vegetables are generally very healthy to include in the diet, certain vegetables are high in minerals that people with kidney disease may need to limit.
- Avocados: Avocados are high in potassium. One avocado weighing around 200 g contains 975 mg of potassium, almost half of the daily recommended amount for those with kidney disease.
- Bananas: A large banana may contain 487 mg of potassium, or a quarter of someone’s recommended daily amount.
- Oranges: Oranges and orange juice are high in potassium. A 250 gram glass of orange juice may contain as much as 441 mg of potassium.
- Dried fruits: Dried fruits are concentrated sources of many of the nutrients found in fresh fruits, meaning it can be easier to exceed recommended daily intakes. People following a renal diet should avoid apricots, dates, prunes, and raisins, which are all high in potassium.
Learn more about high potassium foods here.
Although vegetables contribute vital nutrients to the diet, people with kidney problems should limit their intake of the following:
- Brussels sprouts
- Chinese cabbage
- greens, except for kale
- white mushrooms
- vegetable juices
Although an individual with kidney disease must adapt their diet, there are still many suitable and healthy options.
People should choose foods with lower levels of sodium, potassium, and phosphorus. These include:
- Fruit: apples, cranberries, grapes, pineapple, and strawberries
- Vegetables: cauliflower, lettuce, onions, peppers, and radishes
- Baked goods: pita, tortillas, sourdough bread
- Protein: beef and chicken
- Carbohydrates: white rice, unsalted popcorn
If an individual has chronic kidney disease, doctors typically recommend reducing their intake of potassium, phosphorus, and sodium to help manage the condition. The dietary restrictions depend on someone’s kidney disease stage.
Although there is a long list of foods that are best to avoid on a renal diet, there is also a wide range of healthy foods that people can eat without impacting their kidney health.
An individual may work with a renal dietitian to find the most suitable diet for them.