What Is Hyperphosphatemia and Why Is It Dangerous?
Phosphate is a vital mineral for bone health and cellular function, but an excess of it in the blood, known as hyperphosphatemia, can cause significant health problems. Normally, healthy kidneys filter out and excrete excess phosphate. However, in people with chronic kidney disease (CKD), kidney function declines, and the body's ability to regulate phosphate levels is impaired, leading to a build-up. Chronic, uncontrolled hyperphosphatemia can lead to a host of dangerous complications, including weakened bones (by pulling calcium from them), itchy skin, and serious calcium deposits in the blood vessels, heart, and lungs. These deposits increase the risk of cardiovascular disease, heart attack, and stroke. Managing and removing this excess phosphate is therefore a critical part of care for those with kidney disease.
Dietary Management: The First Line of Defense
Controlling the amount of phosphate you consume is the most important step in preventing it from building up. A key distinction must be made between naturally occurring (organic) phosphate in foods and inorganic phosphate additives.
- Organic vs. Inorganic Phosphate: Phosphate naturally found in foods like meat, nuts, and dairy is less absorbed by the body (40-60%) compared to the inorganic phosphate added to processed foods. These additives, often used as preservatives or flavor enhancers, are almost completely absorbed (around 90%). This makes avoiding processed foods a crucial part of a low-phosphate diet.
- Foods to limit: While all foods contain some phosphate, high-phosphate foods should be limited. This includes many dairy products (milk, yogurt, cheese), nuts and seeds, and processed meats.
- Phosphate Additives: These are often listed on food labels with the word "phos" in the ingredient, such as phosphoric acid, disodium phosphate, and calcium phosphate. Careful label reading is essential.
High vs. Low Phosphate Food Choices
| Food Category | Higher Phosphate Foods (Limit/Avoid) | Lower Phosphate Foods (Enjoy) |
|---|---|---|
| Drinks | Dark colas, bottled teas with additives, sports drinks, beer | Water, herbal tea, coffee (fresh-brewed), lemonade, lemon-lime soda |
| Dairy | Processed cheese, milk, ice cream, most yogurts | Cream cheese, cottage cheese (in moderation), certain vegan cheeses, sorbet |
| Protein | Organ meats (liver, kidney), processed deli meats, sausages, sardines with bones, most nuts | Fresh chicken, turkey, beef, lamb, egg whites, most fresh fish |
| Grains | Bran cereals, whole wheat bread with additives, baking mixes with phosphate | White bread (without additives), cornflakes, rice krispies, rice, pasta |
| Snacks/Desserts | Chocolate, caramel, chocolate candies, snacks with cheese powder | Hard candy, fruit snacks, jelly beans, gumdrops, plain cookies |
Medications: Phosphate Binders
For many patients, especially those with CKD, diet alone is not enough to control phosphate levels. Phosphate binders are medications that prevent the body from absorbing phosphate from the food you eat.
- How They Work: When taken with meals, binders act like a sponge, attaching to phosphate in the gastrointestinal tract. This bound phosphate then passes out of the body in the stool.
- Timing Is Crucial: Binders must be taken with meals or snacks to be effective. Forgetting a dose means the phosphate in that meal will be absorbed. Consistent timing is critical for managing levels effectively.
- Types of Binders: There are different types of phosphate binders, and your doctor will determine the best one for you based on your overall health.
- Calcium-Based Binders: These are widely used but can sometimes cause hypercalcemia (too much calcium in the blood), which can accelerate vascular calcification. Examples include calcium acetate and calcium carbonate.
- Non-Calcium-Based Binders: Options like sevelamer and lanthanum carbonate are often used to avoid the risk of hypercalcemia. Iron-based binders like ferric citrate and sucroferric oxyhydroxide are also available.
Dialysis: A Treatment for Kidney Failure
For individuals with end-stage renal disease (ESRD), dialysis becomes necessary to remove waste products and excess minerals like phosphate from the blood.
- How It Works: Dialysis treatments filter the blood to mimic the function of healthy kidneys. However, the procedure alone is typically not enough to fully control phosphate levels.
- Multi-Faceted Approach: Patients on dialysis still need to adhere to a strict low-phosphate diet and consistently take their phosphate binders. Combining all three strategies—diet, binders, and dialysis—is required for effective management. More frequent or longer dialysis sessions may also enhance phosphate removal.
Can Natural Supplements or Remedies Help?
Some products have been marketed as "natural" phosphate binders, but research suggests they are not effective. For example, studies have shown that chitosan chewing gum cannot adequately reduce phosphate absorption. The most reliable and medically supported methods to reduce phosphate levels are through dietary control and, if needed, prescribed medications and dialysis. Always discuss any dietary changes or supplements with your healthcare provider to ensure they are safe and effective for your specific condition.
Conclusion
Successfully managing and removing phosphates from your body is a comprehensive effort that requires a combination of dietary discipline and, for many, medical intervention. Reducing your intake of highly absorbable inorganic phosphates from processed foods is the first and most critical step. For those with compromised kidney function, this must be paired with the consistent use of prescribed phosphate binders. Finally, individuals with end-stage renal disease rely on dialysis to filter waste, but it must be supplemented with a controlled diet and medication. Following these strategies under the close supervision of a healthcare team is the most effective way to prevent the serious long-term complications associated with high phosphate levels.
For more information on managing your phosphorus intake with kidney disease, consult the National Kidney Foundation's resources: https://www.kidney.org/kidney-topics/phosphorus-and-your-ckd-diet.
