When you are on dialysis it is important to be aware of the phosphorus containing foods you eat and to track the phosphorus levels in your blood test results. In this article you will learn the reasons why this is important and how phosphate binders can help you keep your phosphorus levels in the recommended range for a person on dialysis.
Phosphorus is a mineral found naturally in many foods and preservative additives. The body uses phosphorus to form strong bones and teeth and develop connective tissues and organs. Phosphorus is the second most abundant mineral in the body after calcium. The kidneys play an important role in regulating phosphorus levels in the body. A healthy kidney eliminates the extra phosphorus the body does not need.
Too much phosphorus in the body can cause heart and bone problems, as it depletes calcium from the bones and releases too much parathyroid hormone (PTH), which will weaken the bones. A review of the entire pathway can be found in the previous post "The 2 P’s: P & PTH. What do they stand for and why are they important?" and in the Resources section below the "Secondary Hyperparathyroidism" reference provides useful information about what it is and how to treat it.
Importance of tracking phosphorus levels in your blood
If your kidneys are not working well and you are on dialysis, you will need to take a proactive role in helping maintain the recommended levels of phosphorus in the blood, this includes adjusting your diet, taking any recommended medications and tracking blood phosphorus levels by monitoring your blood test results.
The recommended blood phosphorus level for someone who is on dialysis is 3.5 to 5.5 mg/dL.
You may have a slightly different value range based on your healthcare provider recommendations. To stay on a healthy track, you need to watch your diet and your blood test results from the laboratory on a regular basis as an inadequate amount of phosphorus intake can happen at any time.
How to manage phosphorus through your diet
You can help maintain your phosphorus levels in the recommended blood test result ranges with your food choices, see examples below.
Low-phosphorus food examples:
● Fresh fruits and vegetables
● Unenriched rice milk
● Bread
● Pasta
● Rice
High-phosphorus foods to be avoided or limited:
● Dairy foods (cheese, milk, ice cream, etc.)
● Beans
● Nuts
● Bran cereals
● Processed meats (sausage, bacon, salami, etc.)
● Most dark color sodas with phosphate additives.
How much phosphorus can you take daily?
According to the National Kidney Foundation, the daily recommended intake of phosphorus is 800-1000 mg/day. Unfortunately, since the U.S. Food and Drug Administration does not require phosphorus on nutrition labels, so it will be hard to know and calculate phosphorus intake just by reading the labels. The best way to see if there is phosphorus in a packaged food is to look at the ingredient listing on the nutrition label. Avoiding the “phos” you see in the ingredient listing you can’t pronounce is the best thing to do, such as:
● Disodium phosphate
● Potassium tripolyphosphate, and
● Tetrasodium pyrophosphate.
What happens if you aren’t able to manage your phosphorus with diet alone?
Phosphate binders are a commonly prescribed class of drugs for people on dialysis when the phosphorus level in the blood is too high. The dietitian and doctor may choose different types of phosphate binders based on your needs, this is not dependent on the type of dialysis. Read further to learn the basics of phosphate binders and understand your options.
What are phosphate binders?
Phosphate binders are a prescribed medication that helps you lower the amount of phosphorus in your blood. Common phosphate binders like Renvela work by binding the food with the phosphorus in your gut to prevent it from being absorbed into your blood. The phosphorus in your food that binds with the phosphate binder in your body is then eliminated through your stool. Other phosphate binders work differently in how the phosphate is eliminated, but the end result for all types is that you have less phosphorus in your blood.
How do you take phosphate binders?
You typically take phosphate binders within 5 - 10 minutes before or immediately after meals and snacks. Phosphate binders alone without food will not lower your serum phosphorus levels. They only work when they can bind to the phosphorus in food.
Common types of phosphate binders
Speak with your healthcare provider and dietician to determine which one is right for you.
1. Calcium-based binders commonly used today:
Calcium carbonate (Tums)
Calcium acetate (Phoslo).
Potential side effects: Calcium-based binders have the least side effects on Gastrointestinal (GI) symptoms, however because they are calcium based, there is concern that taking these binders regularly can increase calcium levels in the bloodstream, and that some of this calcium can be deposited in blood vessels and cause organ damage. It is important to take as directed by a dietitian or doctor, and keep track of your calcium levels in your blood tests.
2. Non-calcium-based binders commonly used today:
Sevelamer (Renvela/Renagel) - Most popular
Lanthanum Carbonate (Fosrenol).
Potential side effects: The most common GI symptoms they cause are constipation.
3. Iron-based binders commonly used today:
Ferric Citrate (Auryxia)
Sucroferric Oxyhydroxide (Velphoro).
Potential side effects: Stomach pain and diarrhea.
Note: These are the newest binders on the market. Both are highly effective at binding phosphorus and providing extra iron for anemia. Iron makes your stool black/dark, so it's hard to tell if there is bleeding without a lab test.
Options on how to take phosphate binders
Pill/tablet form:
Simply swallow them with a beverage of choice.
Reminder: Since fluid intake is restricted during dialysis, the more pills you need to take will require you to drink more fluid intake.
Examples: Tums, Phoslo, Renvela, and Auryxia offer tablets.
Chewable form:
Chewable phosphate binders do not require a beverage; helps reduce fluid intake.
Examples: Tums, Fosrenol, and Velphoro are all available in chewable forms.
Powder form:
Rarely seen and most pharmacies will not have these in stock.
Only Renvela comes in this form and is used mostly when a person has swallowing problems.
Don’t skip your phosphate binders!
If you are not able to keep your phosphate within the recommended range provided to you by your physician, and phosphate binders are recommended, make sure you adhere to these recommendations.
Make it a habit to take your phosphate binder after the first bite of your meal!
Resources
1. Phosphorus.The Nutrition Source. Harvard
2. Eating Right for Chronic Kidney Disease. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
3. How to Be a Phosphorous Detective. National Kidney Foundation (NKF)
5. Secondary Hyperparathyroidism. NKF
6. Your kidney-friendly food plan: Managing phosphorus. American Kidney Fund (AKF)
7. Low Phosphorus Diet for Kidney Disease Patients. American Association of Kidney Patients
Note: The OneTrackHealth mobile app allows you to determine if you are within your set test reference ranges for blood tests including phosphorus.
The OneTrackHealth app includes five default blood tests (Albumin, Calcium, Hemoglobin, Phosphorus and Potassium) that are regularly monitored for people with chronic kidney disease on dialysis with the standard recommended blood test result ranges* to make it easier for you and your care partner to keep track of your health goals.
* References used to determine the default test type ranges are included in The Blood Test Results Help Guide located in the OneTrackHealth app. We provide basic reference ranges for your educational purposes and recommend that you consult with your licensed healthcare provider/nephrologist for your specific reference ranges. The OneTrackHealth mobile and web app is customizable, you can add new tests and change the default tests reference ranges via the test edit tool. We recommend consulting with your physician to determine the appropriate ranges for you when adding or editing test result ranges.
