Chronic kidney disease (CKD) occurs when the kidneys become damaged and slowly lose their ability to filter waste and excess fluid from the blood, causing a buildup of harmful substances in the body.

As kidney damage progresses, people often experience symptoms such as swelling, fatigue, chest pain, dry skin, itching, numbness, headache, shortness of breath, and weight loss. Without proper treatment, chronic kidney disease can lead to bone disease, anemia, stroke or heart attack.

People with CKD are often put on a renal (kidney) diet to slow the progression of the disease, relieve symptoms, and maintain nutrient stores. This specialized diet focuses on controlling the intake of specific minerals to protect the kidneys from further damage and balance electrolyte levels.

When following a renal diet, it is essential to carefully manage your sodium, phosphorus, potassium and protein intake.

Low sodium foods

Sodium is an essential mineral that helps maintain fluid balance in the body. However, people with chronic kidney disease should limit their sodium intake, because excess sodium causes the blood to retain more fluid than necessary.

Water retention increases blood volume, leading to hypertension (high blood pressure). This can cause edema (swelling), shortness of breath and pressure on the heart and kidneys. Further damage may develop as the kidneys work harder to handle the increased fluid load.

Sodium recommendations vary depending on the stage of kidney disease and your individual health. A general rule of thumb is to limit your intake to less than 2,300 milligrams per day.

Here are some tips for reduce your sodium intake:

• Season your food with spices, herbs, vinegar, lemon juice and salt-free seasonings
• Use low-sodium sauces and dressings
• Choose unprocessed meats over their processed counterparts
• Choose products labeled “low sodium” or “sodium free”
• Select fresh and frozen fruits, vegetables and protein sources without added seasonings or sauces
• Drain and rinse canned foods with added salt

Foods low in phosphorus

Phosphorus is a mineral that plays a central role in bone health and energy production. The kidneys help maintain balanced phosphorus levels by filtering excess phosphorus from the blood and excreting it in the urine.

Removing excess phosphorus becomes difficult as kidney function declines, leading to phosphorus buildup in people with chronic kidney disease. High levels of phosphorus draw calcium from bones, weakening bone structure.

High levels of phosphorus can also lead to harmful calcium deposits in the lungs, eyes, blood vessels and heart, increasing the risk of heart attack or stroke. Depending on your phosphorus levels, you may be advised to limit your phosphorus intake to 800-1,000 milligrams to reduce these complications.

Foods and drinks low in phosphorus include:

• Fresh fruits and vegetables: Apples, berries, grapes, cucumbers, mushrooms
• Dairy alternatives: Unenriched rice milk and almond milkvegan yogurt and cheese
• Grains: White bread, pasta, rice, corn and rice cereals
• Drinks: Water, coffee, tea, lemonade, drinks without phosphate additives

Foods low in potassium

Potassium is essential for the proper functioning of nerves, muscles and kidneys. People with chronic kidney disease usually maintain normal blood potassium levels until later stages of the disease.

As chronic kidney disease progresses, the kidneys may have difficulty removing excess potassium, leading to hyperkalemia, which is high levels of potassium in the blood. Hyperkalemia can cause muscle weakness, paralysis, nausea, hypotension (low blood pressure), irregular heartbeat and cardiac arrest. People at risk of hyperkalemia should have their blood levels checked regularly.

Foods low in potassium include:

• Fruits: Apples, pears, peaches, berries, grapes, pineapples, plums, watermelons
• Vegetables: Green beans, asparagus, cabbage, cauliflower, zucchini, corn, eggplant, onions, peas
• Grains: White bread, pasta, rice, oatmeal
• Milk alternatives: Rice milk

Adequate protein

Protein is necessary for building and maintaining body tissues and organs, healing wounds, and fighting infections. Using protein to perform these vital functions causes the body to produce waste products that end up in the blood. The kidneys are responsible for eliminating these wastes.

For people with chronic kidney disease, too much protein can increase pressure on the kidneys, leading to further kidney damage. Diets low in protein can alleviate this pressure and reduce the workload on the kidneys.

A lack of protein can lead to malnutrition, which develops when the body lacks essential nutrients. People on dialysis may need more protein because treatments remove proteins from the blood. Working with a registered dietitian (RD) or registered dietitian nutritionist (RDN) can help you get the right balance of protein to meet your individual needs.

Here are some general suggestions:

• Eat smaller portions (2 to 3 ounces) of meat, chicken and fish
• Keep dairy to a minimum (half a cup of milk or yogurt or a slice of cheese)
• Make Plant Protein Half of Your Total Protein Intake to Slow Loss of Kidney Function

Specific foods to avoid on a kidney diet depend on the stage of kidney disease and laboratory test results. People in the early stages are advised to avoid or limit foods high in sodium and protein to reduce kidney strain. In later stages, it also becomes crucial to avoid foods high in potassium and phosphorus.

Foods high in sodium include:

• Salt and savory seasonings: Table, seasoning, garlic, onion, celery and light salts, meat tenderizer
• Salty foods: Crackers, chips, pretzels, tortilla chips
• Salty foods: Ham, bacon, sauerkraut, pickles
• Lunch meats: Cold meats, pastrami, sausages, spam, hot dogs
• Processed foods: Canned goods, TV dinners, frozen ready meals, fast food

Protein-rich foods include:

• Animal sources: Meat, chicken, fish, eggs, dairy products
• Plant sources: Beans and legumes, nuts, seeds

Although beans, nuts and seeds contain protein, plant proteins are gentler on the kidneys than animal proteins. Excess acid can harm the kidneys, and plant proteins produce less acid in the body than animal proteins.

Foods and drinks high in phosphorus include:

• Foods containing phosphate additives: Foods containing dicalcium phosphate, disodium phosphate, monosodium phosphate, phosphoric acid, trisodium phosphate
• Dairy products: Milk, cheese, yogurt
• Protein sources: Oysters, beef liver, fish roe, sardines, chicken liver, offal, processed meats
• Drinks: Beer, cocoa, drinks with phosphate additives, dark sodas
• Other foods: Chocolate, caramels, oat bran (e.g. oat bran muffins)

Foods rich in potassium include:

• Fruits: Bananas, apricots, dates, dried fruits, oranges, orange juice, kiwis, honeydew melons
• Vegetables: Potatoes, beans and legumes, acorn and butternut squash,
  artichokes, beets, leafy vegetables, tomatoes, avocados
• Milkman: Milk, yogurt
• Grains: Bran and bran products, wheat germ, brown rice, nuts, beans, whole wheat bread and pasta

Below you’ll find several ideas for kidney-friendly breakfasts, lunches, and dinners to enjoy throughout the week.

Breakfast

• Whole egg or egg white omelette with red peppers, zucchini, garlic and onion
• Homemade pancakes, scrambled egg whites and mixed red fruits
• Chia seed almond milk pudding topped with pear slices

Lunch

• Mediterranean chickpea salad with cucumbers, red onions and fresh herbs
• Chicken salad with grapes, apples and onions served with white bread
• Fish Tacos with Grilled Corn

Dinner

• Grilled Chicken (3 ounces) with Rosemary Cauliflower Puree and Garlic Asparagus
• Baked salmon (3 ounces) seasoned with dill with a side of green beans and white rice
• Tofu and vegetable fried rice

Snacks

• Celery and peanut butter
• Plain popcorn
• Berry Smoothie with Almond Milk

Diets studied for their effects on kidney disease include the DASH diet and plant-based diets.

THE DASH Dietshort for Dietary Approaches to Stop Hypertension, is a diet designed to lower high blood pressure and slow the progression of heart and kidney disease. It emphasizes the consumption of fruits, vegetables, whole grains, fish, poultry, beans, seeds, nuts and low-fat dairy products, while limiting sodium, added sugar, saturated fats and red meat.

Plant-based diets focus on increased consumption of fruits, vegetables, whole grains, beans, nuts and seeds while limiting or excluding animal products. These diets are rich in fiber, vitamins, minerals and antioxidants that reduce the risk of disease. Studies have shown that plant-based diets can slow or completely stop the progression of kidney disease.

Chronic kidney disease is characterized by kidney damage that reduces the ability to eliminate excess waste and fluids. Sufferers are advised to follow a strict kidney diet to prevent further kidney damage and manage symptoms.

Depending on the stage of kidney disease and laboratory test results, dietary restrictions may include limiting sodium, potassium, phosphorus, and protein intake. Health care providers and registered dietitians or RDNs adjust these recommendations to meet the needs of each person. Regular monitoring and adjustment of diet is necessary to minimize the progression of kidney disease and maintain mineral balance.