Your kidneys play a vital role in regulating the amount of calcium and phosphate in your blood. When you eat foods that contain phosphate, healthy kidneys remove excess phosphate from the blood and deposit it into your urine so that it leaves your body. When you have kidney disease, your kidneys do not filter your blood properly, and excess phosphate accumulates in your blood.
Complications
If your blood contains too much phosphate, the mineral combines with calcium and forms clumps in your blood vessels, which can cause damage to the blood vessels. When calcium combines with phosphate, it also lowers the amount of available calcium in your blood, signaling your bones to release calcium. Over time, this can lead to weak bones, a medical condition referred to as renal osteodystrophy.
Phosphate Binders and Kidney Function
Phosphate binders are most often prescribed for those who are currently on dialysis or those with end-stage renal disease, which is characterized by total, or nearly total, loss of kidney function. In some cases, phosphate binders will be prescribed for kidney patients in the third or fourth stage of chronic kidney disease, which are the stages prior to end-stage renal disease.
How Phosphate Binders Work
Phosphate binders work by binding to dietary phosphate in your digestive tract and turning it into a compound that your small intestine is unable to absorb. Instead of entering the bloodstream, as phosphate would, this new compound remains in your gastrointestinal tract until it is removed from your body through your feces.
The American Association of Kidney Patients notes that phosphate binders must be taken with meals or they will not be effective. This is because they bind to the phosphate in your digestive tract, not the phosphate that has already entered your blood. If you do not take a dose within 30 minutes of consuming a meal, skip that dose.
Importance of Diet
According to the National Kidney Federation, phosphate binders only work in conjunction with a reduced phosphate diet. High phosphate foods, such as milk, yogurt and ice cream, should be limited to less than one serving per day. Cheese intake should be limited to no more than 1 oz. per day and egg consumption should not exceed three to four eggs per week, with a limit of one per day. The specific amount of phosphate you need depends on your individual characteristics, such as age, sex and level of kidney function. If you have kidney disease and are taking phosphate binders, it is important to work closely with a dietitian to develop a healthy eating plan.
