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

As kidney damage progresses, people often experience symptoms such as swelling, fatigue, chest pain, dry skin, itching, numbness, headaches, 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 placed on a renal (kidney) diet to slow disease progression, 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 the kidney diet, it is essential to carefully manage your intake of sodium, phosphorus, potassium and protein.

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.

Fluid retention increases blood volume, leading to hypertension (high blood pressure). It can cause edema (swelling), difficulty breathing, and strain on the heart and kidneys. Additional damage can 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 status. A general rule of thumb is to limit your intake to less than 2,300 milligrams per day.

Here are some tips for reducing sodium intake:

• Season your food with spices, herbs, vinegar, lemon juice and salt-free seasonings
• Use low-sodium dressings and salad 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 and sauces
• Drain and rinse canned goods that contain added salt

Foods low in phosphorus

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

Eliminating excess phosphorus becomes difficult as kidney function declines, leading to phosphorus build-up in people with chronic kidney disease. High phosphorus levels remove calcium from the bones, weakening bone structure.

Elevated phosphorus levels 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 level, 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: Non-enriched rice milk and almond milkvegan yogurt and cheese
• Cereal: White bread, pasta, rice, corn and rice cereal
• Drinks: Water, coffee, tea, lemonade, drinks without phosphate additives

Low potassium foods

Potassium is vital for the proper functioning of nerves, muscles and kidneys. People with chronic kidney disease usually maintain a normal level of potassium in their blood until they reach the later stages of the disease.

As chronic kidney disease progresses, the kidneys may have difficulty getting rid of excess potassium, leading to hyperkalemia — 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, pineapple, plums, watermelon
• Vegetables: Green beans, asparagus, cabbage, cauliflower, zucchini, corn, eggplant, onion, peas
• Cereal: White bread, pasta, rice, sand
• Alternatives to milk: Rice milk

Adequate protein

Protein is needed to build and maintain body tissues and organs, heal wounds, and fight infection. 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 the pressure on the kidneys, leading to further kidney damage. Low-protein diets can reduce this pressure and reduce the workload of the kidneys.

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

Here are some general suggestions:

• Eat smaller portions (2-3 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 the loss of kidney function

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

Foods high in sodium include:

• Seasonings with salt and salt: Table, spices, garlic, onion, celery and light salts, meat tenderizers
• Salty foods: Crackers, potato chips, pretzels, tortilla chips
• Treated foods: Ham, bacon, sauerkraut, pickles
• Lunch meat: Deli, pastrami, sausage, spam, hot dog
• Processed foods: Canned foods, TV dinners, frozen meals, fast food

Foods rich in protein include:

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

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

Foods and drinks high in phosphorus include:

• Foods with 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, organs, processed meat
• Drinks: Beer, cocoa, drinks with phosphate additives, black sodas
• Other foods: Chocolate, caramels, oat bran (eg oat bran muffins)

Foods rich in potassium include:

• Fruits: Bananas, apricots, dates, dried fruits, oranges, orange juice, kiwi, watermelons
• Vegetables: Potatoes, beans and legumes, acorns and pumpkin,
  artichokes, beets, leafy greens, tomatoes, avocados
• Dairy: Milk, yogurt
• Cereal: Bran and bran products, wheat germ, brown rice, nuts, beans, bread and wholemeal pasta

Below are some kidney-friendly breakfast, lunch and dinner ideas to enjoy throughout the week.

Breakfast

• Omelet with whole egg or egg white with red pepper, zucchini, garlic and onion
• Homemade pancakes, egg whites and mixed berries
• Chia seeds pudding made with almond milk and topped with sliced ​​pears

Lunch

• Mediterranean chickpea salad with cucumber, red onion and fresh herbs
• Chicken salad with grapes, apples and onions with white bread
• Fish tacos with a side of fried corn

Dinner

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

STARTERS

• Celery and peanut butter
• Simple popcorn
• Berry smoothie made with almond milk

Diets researched for their effects on kidney disease are the DASH Diet and plant-based diets.

The The DASH dietshort for Dietary Approaches to Stop Hypertension, is a dietary plan designed to lower high blood pressure and slow the progression of heart and kidney disease. Emphasize fruits, vegetables, whole grains, fish, poultry, beans, seeds, nuts, and low-fat dairy products while limiting sodium, added sugar, saturated fat, and red meat.

Plant-based diets focus on an increased intake 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 lower 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 damage to the kidneys that reduces the ability to eliminate excess waste and fluid. People with the condition are advised to adhere to a strict renal 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. Healthcare providers and RDs or RDNs tailor these recommendations to meet each individual’s needs. Regular monitoring and adjustment of the diet is necessary to minimize the progression of kidney disease and to maintain mineral balance.