The Cornerstone of the Hemodialysis Diet: What to Limit
For patients on hemodialysis, dietary restrictions are not arbitrary but are a direct response to the impaired function of the kidneys. The kidneys are no longer able to effectively filter waste products, excess minerals, and fluid from the blood. Hemodialysis treatments perform this function, but the buildup between sessions necessitates strict dietary controls to prevent complications and make treatments more effective. A registered renal dietitian is a key partner in creating a tailored meal plan based on your lab results and individual health needs.
Limiting Fluid Intake
One of the most critical restrictions for in-center hemodialysis patients is managing fluid intake. As kidney function declines, so does urine output. This means extra fluid stays in the body between dialysis sessions, leading to swelling, shortness of breath, and dangerously high blood pressure. Fluid isn’t just water; it includes anything that is liquid at room temperature, such as:
- Coffee and tea
- Milk, milkshakes, and juice
- Ice cream, popsicles, and sherbet
- Soups, broths, and gravy
- Gelatin and pudding
- Salty foods, which can increase thirst and cause a patient to drink more
Patients on home hemodialysis or peritoneal dialysis may have different, often less restrictive, fluid guidelines due to more frequent treatments. To help manage thirst, patients can suck on hard candies, chew gum, or rinse their mouth with water without swallowing.
Controlling Sodium (Salt)
Sodium is a key driver of thirst, and excessive intake makes it extremely difficult to stick to a fluid restriction. Too much sodium also contributes to high blood pressure, increasing the risk of cardiovascular problems. Most of the sodium in a modern diet comes not from the salt shaker but from processed and prepared foods. Patients must become label-reading experts to identify hidden sodium sources, which are abundant in:
- Canned goods (soups, vegetables)
- Processed meats (bacon, deli meats, hot dogs)
- Fast food and restaurant meals
- Salty snacks (chips, pretzels, crackers)
- Condiments (soy sauce, barbecue sauce, salad dressings)
Using herbs, spices, and salt-free seasoning blends is an excellent way to add flavor without the sodium load.
Managing Potassium Levels
Potassium is a mineral vital for nerve and muscle function, including the heart. Healthy kidneys regulate potassium levels, but when kidney function fails, potassium can build up to dangerous levels, causing an irregular heartbeat or even cardiac arrest. Not all dialysis patients need to restrict potassium, but many do, based on their blood test results. Common high-potassium foods to limit or avoid include:
- Fruits: Bananas, oranges, cantaloupe, dried fruits (raisins, prunes)
- Vegetables: Potatoes, tomatoes, cooked spinach, avocados
- Dairy: Milk, yogurt, ice cream
- Other: Nuts, seeds, beans, salt substitutes containing potassium chloride
Some vegetables, like potatoes, can have some potassium removed by a process called leaching, which involves peeling, dicing, and boiling them in a large amount of water.
Reducing Phosphorus Intake
Excess phosphorus is not effectively removed by hemodialysis and can cause calcium to be pulled from the bones, making them weak and brittle. This imbalance can also lead to painful calcium deposits in blood vessels and itchy skin. A major source of concern is inorganic phosphorus, which is added to processed foods and is almost completely absorbed by the body. A renal dietitian will advise on limiting foods high in natural phosphorus and, crucially, avoiding foods with phosphate additives. High phosphorus foods include:
- Dairy: Milk, cheese, yogurt
- Processed Foods: Processed meats, fast food, cola beverages, and foods containing additives with “PHOS” in the ingredient list
- Nuts and seeds: These also tend to be high in potassium and should be limited
- Whole Grains: Brown rice, whole wheat bread
Phosphate binders may be prescribed by a doctor to help prevent the body from absorbing some phosphorus from food.
Understanding Your Protein Needs
One significant difference between pre-dialysis and dialysis diets is the protein requirement. While patients with earlier-stage kidney disease are often advised to limit protein, those on hemodialysis need a higher protein intake. This is because protein is lost during the dialysis process. High-quality protein helps maintain muscle mass, strengthens the immune system, and aids in tissue repair. Excellent sources of high-quality protein include:
- Lean meat, poultry, and fish
- Eggs (especially egg whites, which are low in phosphorus and cholesterol)
- Some dairy products (if potassium and phosphorus levels allow)
- Plant-based proteins with lower phosphorus-to-protein ratios, such as egg whites
Key Dietary Comparisons for Hemodialysis Patients
| Nutrient | High-Intake Example | Lower-Intake Alternative | Why it Matters |
|---|---|---|---|
| Potassium | Bananas, Avocados, Oranges | Apples, Grapes, Berries | High levels can cause dangerous heart rhythm abnormalities. |
| Phosphorus | Dairy products, Colas, Processed meats | Unenriched rice milk, Clear sodas, Fresh poultry | Pulls calcium from bones, leading to weak bones and cardiovascular issues. |
| Sodium | Canned soups, Deli meats, Chips | Homemade soups, Fresh poultry, Unsalted crackers | Increases thirst, which leads to excessive fluid intake and high blood pressure. |
| Fluid | Juice, Milkshakes, Soups | Water from a controlled portion, Ice chips, Hard candies | Excess fluid can build up between dialysis sessions, straining the heart and lungs. |
| Protein | Processed, cured meats | Lean, high-quality sources like fish, eggs, and chicken | High-quality protein is needed to replenish losses from dialysis treatment. |
Cooking and Preparation Tips
Adhering to a renal diet requires conscious effort, but small changes in cooking and preparation can make a big difference:
- Prioritize Fresh Ingredients: Choose fresh or plain frozen vegetables and lean meats over processed, canned, or packaged foods.
- Flavor with Herbs and Spices: Replace salt with herbs like oregano, garlic powder, onion powder, and paprika. Fresh citrus juice or vinegar can also add a burst of flavor.
- Double-Boil High-Potassium Veggies: Use the leaching method for potatoes and other high-potassium root vegetables by peeling, dicing, and boiling them in a large pot of water to reduce their potassium content.
- Beware of Hidden Additives: Read labels carefully for ingredients that contain “phos” (e.g., sodium phosphate) or potassium chloride, often found in salt substitutes.
- Control Portion Sizes: Even with lower-potassium or phosphorus foods, portion control is key to staying within recommended daily limits.
- Use Water Wisely: Measure and ration your daily fluid allowance. Use smaller cups for drinks and opt for ice chips to satisfy thirst with less fluid.
Conclusion
Navigating the complex dietary restrictions that accompany hemodialysis is a challenging but necessary part of treatment. By proactively managing fluid intake and carefully controlling sodium, potassium, and phosphorus levels, patients can significantly improve their overall health and treatment outcomes. Focusing on fresh, minimally processed foods, using high-quality protein, and working closely with a renal dietitian are vital steps. While it may seem restrictive, a well-managed renal diet is a powerful tool for feeling better, staying healthier, and living well with kidney failure. Consistent lab monitoring is the best way to ensure the diet is meeting individual needs and to adapt restrictions over time.
Learn more about managing kidney disease with nutrition from the National Kidney Foundation.
