Learn how to keep your bones healthy

Download our infographic and learn how how your kidneys keep your bones healthy.

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Phosphorus is a mineral found in many foods. It works with calcium and vitamin D in your body to keep your bones healthy and strong.

Healthy kidneys help keep the right amount of phosphorus in your body. When you have kidney disease, your kidney cannot do this job as well, allowing phosphorus to build up to dangerous levels in your blood.

Having too much phosphorus in the blood is a condition called hyperphosphatemia.

Learn how to keep your bones healthy

Download our infographic and learn how how your kidneys keep your bones healthy.

Descargue una versión en español de la infografía

Download infographic

What is phosphorus?

Phosphorus is a common mineral. It is found in many foods, drinks and even some medicines.

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Where does phosphorus come from?

Phosphorus in your body comes from three places:

  • The food you eat
  • What you drink
  • The medicines you take

Foods and drinks that are very high in phosphorus include:

  • Milk and cheese
  • Fish
  • Red meat
  • Dried beans and peas
  • Nuts and nut butters
  • Whole grain bread
  • Bran
  • Cocoa
  • Dark-colored sodas
  • Beer

Foods that are low in phosphorus include:

  • Fresh fruits
  • Fresh vegetables

Download the phosphorus food guide to find out about phosphorus in many common foods.

For more information on keeping track of phosphorus in the foods you eat, recipes low in phosphorus, and cooking demonstrations for low-phosphorus recipes, visit Kidney Kitchen.

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What is high phosphorus (hyperphosphatemia)?

The normal amount of phosphorus in the blood (also called serum phosphorus) is between 2.5 – 4.5 mg/dL. This is for an otherwise healthy person. Click here for what your phosphorus numbers should be when you have kidney disease.

Having too much phosphorus in your blood is also called hyperphosphatemia. Too much phosphorus in your blood can cause problems. One of these problems is bone disease.

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How are high phosphorus and bone disease related?

Phosphorus works with calcium and vitamin D in your body to keep your bones healthy and strong.To do this, your body’s phosphorus, calcium and vitamin D all need to be in balance.

When you have too much phosphorus in your blood, it causes your body to pull calcium from your bones to try and keep your blood balanced. This can cause your bones to become weak and unhealthy. Unhealthy bones put you at higher risk of breaks (fractures) and other problems.

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How do kidneys keep bones healthy?

Healthy kidneys also help keep your bones healthy. They do this in two ways:

  • Your kidneys keep the right amounts of phosphorus and calcium in your body. When your kidneys are not working well, too much phosphorus can build up in your blood. This is called hyperphosphatemia.
  • Your kidneys also help your body use vitamin D. When your kidneys are not working, your body may not be able to use vitamin D like it should. This can also cause your bones to get weak.

Too much phosphorus or not enough vitamin D in your blood puts you out of balance. Your body tries to "fix" this using a hormone called parathyroid hormone (PTH). PTH pulls calcium from your bones to try and put your blood back in balance. This loss of calcium can eventually cause bone disease.

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What does early kidney disease do to my bones?

As you read above, you need healthy kidneys to keep healthy bones. When you have kidney disease your bones are also at risk.

In the very early stages of CKD, you will probably not have any problems with how your body controls your phosphorus. However, if your kidney disease gets worse, you may also start to have problems controlling your phosphorus.

Talk to your doctor about what your phosphorus levels should be. Learn about the tests and symptoms of bone disease here

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What does kidney failure do to my bones?

As kidney disease gets worse, so do many other problems. When your kidneys fail and you need dialysis or a transplant, you will need to be very careful in how you manage your phosphorus. The good news is, there are many ways to manage your phosphorus through medicine and diet.

Talk to your healthcare team about how to best manage your phosphorus so that you prevent bone disease. How you manage your phosphorus will depend on several things, including:

  • Your usual diet
  • The kind of dialysis you are doing
  • The medicines you are taking
  • How your lab numbers are doing

If you are on dialysis, it is very important that you do not skip dialysis treatments! Your doctor may also suggest changing the number and length of dialysis sessions to get rid of extra phosphorus.

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Do I need to worry about bone disease after a kidney transplant?

Yes. Bone disease can still occur even after you have a kidney transplant. This can happen for several reasons, but the most common being:

  • Damage to your bones from your kidney disease before the transplant
  • Side effects of the medicines that stop your new kidney from being rejected (also called immunosuppressants).

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How do I prevent bone disease?

If you have kidney disease, it is important to manage your phosphorus levels. This can help prevent bone disease.

Steps you can take to manage your phosphorus levels include:

  • Take a phosphate binder
    • This is a pill you take with meals
    • Keeps your body from absorbing the phosphorus from foods and drinks
    • Help keep phosphorus from building up in your blood.
  • Limit how much phosphorus you eat and drink each day.
    • Ask your doctor or dietitian how much phosphorus you should have daily.
    • Download our phosphorus food guide for information on amounts of phosphorus in common foods.
  • Take a calcitriol supplement.
    • A supplement that helps your body use the calcium and phosphorus it needs.
  • Exercise and increase your daily activity. The more you do this, the more phosphorus your body gets rid of!
  • Do not smoke or use tobacco.
  • Take your all medicines exactly as your doctor prescribes. 

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How will I know if I have bone disease?

Bone disease often does not have any symptoms until your bones are very weak. The only way to know if you have, or are at risk for, bone disease is to be tested.

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What are some blood tests for kidney disease?

Blood tests for bone health usually include the following:

Test Name What does the test check for?
Phosphorus blood test

Note: This is sometimes listed on lab results as "phosphate"
Checks the level of phosphorus in the blood. A high level means too much phosphorus is in your blood. This is called hyperphosphatemia.
Parathyroid hormone (PTH) blood test Checks the level of PTH in your blood. Too much PTH in the blood can be a sign of a problem.
Too much phosphorus or not enough vitamin D in your blood puts you out of balance. Your body tries to "fix" this using a hormone called parathyroid hormone (PTH). PTH pulls calcium from your bones to try and put your blood back in balance. This loss of calcium can eventually cause bone disease.
Calcium blood test Checks the amount of calcium in  your blood. Calcium levels tend to get lower as kidney function worsens. This occurs for many reasons. Calcium levels in your blood are looked at along with phosphorus, vitamin D and PTH levels to determine bone health.  
Vitamin D blood test Checks the level of vitamin D in the blood. Active Vitamin D is used by your body to keep bones strong and the right levels of phosphorus and calcium in the blood. Healthy kidneys activate vitamin D from food, vitamin D supplements and sunlight so your body can use it.

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What are the other tests for bone disease?

Bone disease, or damage to the bones, can be caused by having a high level of phosphorus in the blood over time. To prevent bone damage, your doctor may recommend a combination of medicines, diet changes, and exercise.

To know for certain whether your bones have been damaged, you may have to have more than blood tests. Other tests for bone health might include:

Test Name What does the test involve?
Bone density scanUses X-rays to see how many grams of calcium and other bone minerals are packed into a segment bone.
X-rayCreates a picture of a bone and is used to view and assess the bone for signs of damage.
Bone biopsy A piece of tissue is removed from the bone and checked under a microscope for signs of bone damage.
Physical examYour body is checked carefully to find visible changes in bone structure.

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Questions to ask your doctor (nephrologist)

Managing your phosphorus is one of many things your doctor might talk about when you are diagnosed with kidney disease.

Here are some questions you can bring with you to your appointment to ask your nephrologist:

  • Do I need to worry about my phosphorus level at my stage of kidney disease?
  • What should my phosphorus levels be?
  • How often should I have my phosphorus blood levels checked?
  • When should I start thinking about limiting the phosphorus in my diet?
  • Should I take phosphate binders?
  • Are there different types of phosphate binders?
  • Which binder should I take?
  • When do I need to take my phosphate binders? Before I eat a meal, after, or during?
  • How often do I need to take phosphate binders?
  • How many phosphate binders should I take?
  • Would you recommend any other medicines?
  • Can exercise help lower my phosphorus?
  • Will dialysis remove any phosphorus?
  • What happens if my phosphorus is not controlled? What symptoms should I look out for?

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Questions to ask a dietitian

  • How much phosphorus do you recommend I eat every day/week?
  • What's the best way to track the amount of phosphorus I eat?
  • How do I find phosphorus on a food label?
  • When do I need to take my phosphate binders? Before I eat a meal, after, or during?
  • Do my blood test results show my phosphorus level at just that moment or over time?
  • Are there any foods I should completely avoid?
  • What is the difference between natural and added phosphorus? Is one type better than the other?
  • Is there any way to remove or reduce phosphorus in food?
  • What should I do when eating from a restaurant?

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Webinars on phosphorus

For more information about managing phosphorus, check out our webinars on phosphorus for people with kidney disease.

Phosphorus in the Kidney Disease Diet
Phosphorus in the Kidney Disease Holiday Diet

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Resources for professionals

Take our free online continuing education (CE) course on Managing Hyperphosphatemia

The goals of this course are to:

  • Identify and understand the challenges dietitians and other allied health professionals face in managing hyperphosphatemia in their patients.
  • Describe the different metabolism and impact of organic and inorganic phosphorus sources and identify food sources of both.
  • Identify effective tools and strategies health professionals can employ in their own practice. 

CE credits: 1.00 Commission on Dietetic Registration (CDR); 1.20 NANT; 1.00 Attendance

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