May 08, 2025
Phosphorus is a very important mineral that helps keep bones strong, repairs cells, gives us energy, and is vital to lung function. But it can also cause serious health issues for people with later-stage kidney disease.
Dr. Jay Wish, a Professor of Clinical Medicine, and Dr. Katie Cardone, a clinical pharmacist, break down what phosphorus is, why it matters for kidney health, and how to keep levels in check.
Phosphorus
Phosphorus is a mineral the body needs to survive.
"Phosphorus is primarily found in the bones,” Dr. Cardone said. “It is necessary for bone health and helps with other functions like energy production, cell growth, and nerve function.”
Everyone needs phosphorus, but people with advanced kidney disease may have trouble removing the excess.
"The kidneys are responsible for maintaining safe levels of minerals like phosphorus,” Dr. Cardone said. “Too much or too little can hurt the body."
There Are Two Forms of Phosphorus
There Are Two Forms of Phosphorus
Organic Phosphorus
Found naturally in foods like meat, fish, dairy, beans, and nuts. The body absorbs 40–60% of this type of phosphorus.
Inorganic Phosphorus
Added to processed foods as a preservative or flavor. The body absorbs up to 100% of this type of phosphorus.
"Virtually all people on dialysis have high phosphorus levels if left untreated, unless they are malnourished. Phosphorus is in almost all food, whether from animals or vegetables. However, animal products have higher levels due to the protein content," said Dr. Cardone. "It's the inorganic or added phosphorus we want people to avoid."
Effects of High Phosphorus (Hyperphosphatemia)
As kidney function declines, phosphorus builds up in the blood.
"Phosphorus and calcium like each other—they combine to form bones, teeth, and fingernails,” Dr. Wish said. “But if blood phosphorus levels are high, it decreases calcium in the blood.”
Decreasing calcium triggers a gland in the neck to make a hormone that pulls calcium from the bones to keep blood levels stable.
"This function weakens bones. But the damage doesn't stop there,” said Dr. Wish. “High levels of calcium and phosphorus can combine in the blood and deposit on the walls of small blood vessels, called small vessel disease."
Calcium and phosphorus deposits can lead to an increased risk of:
- Vascular or blood vessel disease
- Bone issues like increased fracture risk
- Heart failure
- Stroke
- Heart attack
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Treating High Phosphorus
Maintaining healthy phosphorus levels is an important part of managing kidney disease. But for people with advanced kidney disease, staying within the typical phosphorus range of 2.5 to 4.5 mg/dL can be challenging.
“The guidelines don’t set a strict phosphorus target for people with advanced kidney disease,” said Dr. Cardone. “Instead, your healthcare team will help determine a safe and realistic goal for you.”
Since phosphorus is found in nearly all foods, managing it usually requires a combination of dietary changes, dialysis adjustments, and medication.
Two Common Medications for High Phosphorus
Two Common Medications for High Phosphorus
Phosphate Binders
Phosphate binders are the most common medications used to control high phosphorus. They attach to phosphorus in food before it's absorbed in the intestines, allowing it to pass out of the body in the stool.
Phosphate Blockers
Phosphate blockers are a newer class of medications that help reduce phosphorus by blocking its absorption in the intestines.
"Phosphate blockers are typically used in combination with traditional phosphate binders," Dr. Wish said. "They can help patients reach their target phosphorus levels more effectively."
Treating high phosphorus has been an ongoing challenge for Quenton Turner Gee, an in-center hemodialysis patient.
"Everything has phosphorus in it. I have to read every nutrition label to avoid added phosphorus," Quenton said. "Good nutrition wasn’t enough. I started a phosphate binder, but it didn't work. I recently added a blocker to my medication routine. I’m waiting to see if it works."
Regardless of your medications or diet restrictions, tracking phosphorus levels from appointment to appointment is important.
"Keep track of your numbers and look for trends,” Dr. Cardone said. “We want to see if you’re moving closer or further away from 'normal'.”
And remember not to blame yourself if you struggle with high phosphorus.
"Trust your doctor. If they tell you it isn't your fault, believe them. It's easy to blame yourself for eating or doing the wrong things," Quentin said. "Kidney disease will pick on anyone. Listen to your doctor and do your best."
Learn more about high-phosphorus treatments.
*This content is provided for informational use only and is not intended as medical advice or as a substitute for the medical advice of a healthcare professional.
