Phosphorus is the second most common mineral in the body (after calcium). Its job is to help your body use energy, and to build strong bones and teeth. Like potassium, extra phosphorus is removed by healthy kidneys. When your kidneys don’t work, phosphorus can build up in your body. This will cause severe itching for some people with diabetes.
Renal bone disease can be a long-term problem associated with some types of dialysis. Over time, losing calcium from the bones makes them weak, frail, and painful. When calcium and phosphorus are out of balance, the parathyroid glands in your neck make too much parathyroid hormone (PTH). Too much PTH causes even more calcium to be pulled out of your bones– it is a vicious cycle.
But renal bone disease does not have to happen. If you keep your calcium and phosphorus levels in the safe range, the cycle won’t start, and your bones and whole body can stay healthy. Ask your dietitian about what your calcium, phosphorus, calcium-phosphorus product, and PTH levels should be while receiving peritoneal dialysis or hemodialysis treatments. The normal ranges for a person on dialysis are about:
Calcium: 8.4 to 10.2 mg/dL
Phosphorus: 3.0 to 5.5 mg/dL
Intact PTH: 150 to 300 pg/mL or 150 to 600 pg/mL as prescribed by a physician
Your monthly blood tests will tell you if you are succeeding.
Keeping Calcium and Phosphorus in the Safe Range
There are three ways to keep your calcium and phosphorus in the safe range:
- Take phosphate binders
- Make careful food choices
- Get complete dialysis treatments or a kidney transplant
Take phosphate binders
Phosphorus is very common in most foods. In fact, it is so common that it would be almost impossible to keep safe phosphorus levels just by eating the right foods. Taking phosphate binders allows you to choose from a wider range of foods. Phosphate binders are medications that remove the extra phosphorus from your system so they can be excreted in your stool. Talk with your doctor and dietitian about how many phosphate binders you need to take with meals and snacks. Take your binders within 5 to 10 minutes of eating snacks and meals. Take fewer binders with a snack or small meal, and more binders with a big meal. They will help you keep your bones healthy.
Make careful food choices
You can’t manage phosphorus just by watching what you eat - but it helps a lot. Phosphorus is found in high-protein foods, like meats and dairy products, and in low-protein foods, like nuts and dried beans. Other common high-phosphorus foods include cola drinks and chocolate. Phosphorus is also found in processed foods, like breakfast cereals (especially whole-grain cereals). You may need to limit phosphorus in foods to about 800 to 1,200 mg/day while on dialysis. Does this mean you can never eat these foods again? No. If you want a food that is high in phosphorus, try to eat smaller portions, take extra binders, and plan the rest of your food for the day to save some “room.”
There are several tools you can use to keep phosphorus under control:
- Read ingredient labels, especially in the grocery store. Look for the word “phosphate” (sometimes appears within a longer name, such as sodium tripolyphosphate). Download our handy label guide “Phosphorus – It Adds Up!”. You can also learn about hidden phosphorus in meats in this article from a renal dietitian.
- When preparing meals, pay attention to nutrition information provided with most recipes. Our Recipe Center is a great resource for foods that can help you keep variety in your diet while you mind your levels of phosphorus. You can download "Phosphorus in Foods", a quick guide to phosphorus amounts in common foods.
- Talk to your nephrology care team, especially your dietitian, about ways to manage phosphorus, including what to look for when grocery shopping and planning meals.
Have complete dialysis treatments or get a kidney transplant
Your dialysis treatments help to reduce the amount of phosphorus in your blood. Complete all of your dialysis treatments as prescribed by your physician so you have as much extra phosphorus being removed from your body as possible. The more dialysis you get, the better your chances of keeping your lab results stable, which is why it is very important not to skip treatments and to stay for the entire treatment every time. Consider alternative methods of dialysis that accommodate longer treatments, such as Nocturnal (overnight) In-Center Dialysis if it is offered in your area, or Home Dialysis (Home Hemodialysis or Peritoneal Dialysis).
Not all antacids are good binders. Some calcium-based antacids may be used safely by people on dialysis to bind extra phosphorus. But some may contain aluminum or magnesium. These can build up to toxic levels in people on dialysis. Always read labels and ask your doctor, pharmacist, or dietitian before taking any over-the-counter products.
Phosphorus in Foods (pdf, 134K)
Get a quick guide to learn about the amount of phosphorus in common foods.
Phosphorus - It Adds Up!
Learn about hidden phosphorus in meats in this article from a renal dietitian.