The Need to Limit Fluids

Kidneys help manage the amount of fluid in your body. When your kidneys fail, the amount of fluid can build up and cause serious complications to your heart and lungs.   If you are on dialysis, the amount of fluids you consume between treatments is important to maintaining a healthy balance and preventing health complications.

Why Should I Care About Restricting My Fluids?

Too much fluid gain between treatments can lead to:

• Cardiac arrest
• Heart disease
• Vein damage
• Blood pressure-related issues
• Swelling
• Fluid build-up in the lungs
• Cramping during treatment

Your fluid restriction is determined by several factors including urine output and fluid input between treatments, which may result in weight gain between treatments.  Fluid control is important for hemodialysis patients because treatments for in-center patients are only done three times a week, compared to daily peritoneal dialysis or short, daily home hemodialysis which can be done five to seven days a week which removes the fluid more frequently.

Your Dry Weight

Your dry weight is the amount of body weight minus the extra fluid that is stored in your body. It is similar to the weight after urination, in a person with fully functioning kidneys. As a dialysis patient, your dry weight is the amount that you weigh shortly after treatment. Using your weight change between treatments can help determine what your restriction will be.

Tips to Control Fluid

Your medical team will help you determine what your fluid restriction will be. Your dietitian can be helpful with tips to avoid taking in too much fluid between treatments as well as learning how to monitor your fluid intake. However, it is up to you to manage your daily intake. Keeping a journal will help you track the amount of fluid you drink and the amount of fluid in your food.  

• Minimize the amount of your sodium intake. As discussed here, sodium causes you to retain fluid and can make you feel thirstier.
• Evenly distributing your fluid throughout the day helps keep you from having dry mouth.
• Gum and tart items such as lemon juice can stimulate your salivary glands to wet your mouth.
• Small cups can help you portion out your liquid better.
• Although ice is really water, and counts as a liquid, it can help satisfy your thirst without adding a lot of fluid. A medium ice cube has approximately one ounce of water.
• An alternative to drinking water with medication is to take meds with food like applesauce which cuts down on more fluid intake.
• Items to watch more carefully are those that are liquid at room temperature (things that melt) and high water fruits and vegetables.
• Understand that almost everything you eat has some water content and contains “hidden fluid”.

Hidden Fluid

When most people think about fluid, they only think about liquids like water or juice. Drinks do have the most fluid content, but items such as yogurt, Jell-O and many fruits and vegetables have large hidden water content. Even items such as meat and bread have some moisture.

Although it is important to understand almost all items contain water, this information should just be another tool in your diet. You shouldn’t avoid corn because it has two ounces of water per ear, but should just understand that if you ate a several ears, you are adding fluid to your diet.  Items to watch more carefully are those that are liquid at room temperature (things that melt) and high water fruits and vegetables.

Watching for hidden fluid can help you keep your weight gained between sessions down and make the process more enjoyable. If you need to take off less fluid during dialysis, you can have quicker treatments or have the filtration rate at a more comfortable level.

Ice cubes can be a great low fluid way to get rid of dry mouth, but remembers that ice is another common item that doesn’t get counted as fluid. A medium ice cube has approximately one ounce of water.

The following is a chart of some commonly eaten foods and their water content:

Phosphorus is commonly found in foods such as dairy, organ meats, fish, poultry, eggs, whole grain products, nuts, and is unusually high in processed foods. Healthy kidneys help your body keep a balance of phosphorus and other minerals you need by filtering out what you don’t need.

When kidneys aren’t working well, phosphorus can build up, causing a condition known as hyperphosphatemia (hi-per-foss-fuh-TEE-mee-uh). If not treated, it can lead to serious health problems. Your phosphorus level should be within the range of 3.5-5.5 mg/dL. Check with your dietitian or doctor if you don’t know your phosphorus level. A simple blood test will let you know what your levels are.

High Phosphorus Foods and Alternatives

The chart below from the National Kidney Foundation (NKF) shows basic ways to substitute high phosphorus foods for low alternatives.

Looking for Hidden Phosphorus

Certain buzz words such as “enhanced meat” found mainly in poultry products may contain hidden phosphorus. Another good rule of thumb is to avoid items that have additional fluid such as a brine added to them. In general, brown colas contain high levels of phosphorus while clear drinks tend to have less. If you have a question and can’t tell by the label contents, ask your dietitian. Sometimes phosphorus is listed on labels as a more complex combination of ingredients. The following is a list of terms that means phosphorus is found in that food.

The following ingredients add phosphorus to foods and should be avoided:

• Sodium polyphosphate
• Sodium tripolyphosphate
• Phosphoric acid
• Disodium phosphate
• Monosodium phosphate
• Potassium tripolyphosphate
• Sodium acid pyrophosphate
• Sodium hexametaphosphate
• Tetrasodium pyrophosphate
• Trisodium triphosphate

The Effects of Too Much Phosphorus

Symptoms of hyperphosphatemia may include cramps, numbness or tingling, itchy skin, bone pain, or joint pain. However, you may not experience any symptoms at all. It’s important that you work with your Renal Dietitian and monitor your blood levels regularly through your monthly labs.

If high phosphorus levels are not treated, they can lead to:

• Sore, weak, and brittle bones
• Painful calcification (mineral buildup in your vessels and valves causing heart damage and failure.
• Calcium buildup in your vessels and valves causing heart damage and failure.

Dialysis alone can’t get rid of the extra phosphorus. That’s why dietitians encourage patients to reduce the amount of phosphorus in their meals and sometimes medication like phosphate binders are prescribed to help the body eliminate excess phosphorus.

Potassium is also important in your diet because potassium levels control nerve and muscle functions. Since healthy kidneys remove excess potassium, most pre-dialysis and dialysis patients have too much potassium in their diet. Potassium intake is less of an issue for PD patients and for hemodialysis patients who do dialysis more than three times weekly, due to the more constant cycling of fluid.

Hyperkalemia or high levels of potassium in the body is associated with a significant increase in an irregular heartbeat and sudden death.

It is difficult to limit potassium in your diet, since most foods have at least some in them.

A few helpful steps to keep you lower your potassium intake includes:

• Watching portion sizes of fruits and vegetables
• Rinsing canned fruits and vegetables
• Replacing dairy products with non-dairy substitutes
• Avoiding salt substitutes
• Leaching (a soaking process before cooking) your vegetables
• Tracking your potassium levels and share any drastic changes with your dietitian

Studies have shown that a low-protein diet (hypoproteic) can help postpone dialysis.

Protein is important in your diet because it helps keep the body nourished and healthy to fight off potential infections, repair tissue and for growth. Quality sources of protein include lean red meat, chicken, turkey, fish, lean pork, dairy and egg products. To keep a healthy diet overall it is best to select trimmed cuts of meat or low-fat dairy. Nuts and beans are also a good source of protein, but they also contain phosphorus.

The chart below was derived from data in the United States Department of Agriculture (USDA) National Nutrient Database for Standard Reference, Release 20.

Sodium is one your body’s major electrolytes that helps control the fluid content of your tissues and cells. Most people know sodium as salt, but salt is a compound made up of sodium and chloride. Healthy kidneys remove excess sodium from the body. Too much sodium is an issue because fluid will build up leading to higher blood pressure and potentially heart failure. Sodium will also make you feel thirstier and make it more difficult to keep within your recommended fluid restrictions.  Home hemodialysis and PD patients don’t need to watch their sodium intake as closely as in-center hemodialysis patients, but they still need to limit their sodium intake for their overall health. Many foods that you eat have sodium, and of course some are better for you than others.

High levels of sodium can lead to:

• Swelling (edema) throughout your body
• High blood pressure (hypertension)
• Heart failure
• Shortness of breath

Low sodium choices include:

• Fresh fruits and vegetables
• Unsalted popcorn
• Breads
• Pastas
• Unprocessed meats

High sodium choices to avoid include:

• Processed meats such as ham and luncheon meats
• Chips
• Salty snack foods
• Canned soups and vegetables
• Tomato juice
• Sports drinks
• Many fast or convenience foods

To help you manage your sodium intake:

• Keep a food journal to track your dietary sodium
• Record your weight daily to track swelling
• Limit processed foods
• Choose low sodium alternatives and don’t add additional salt to meals
• Read food labels and look for hidden sodium in items like drinks or in canned goods
• Use natural flavor enhancers like spices and herbs as a substitute for salt