A. Phosphorus is a mineral found in our body, about 85 percent of which is in our bones. Along with calcium, phosphorus is needed for building healthy and strong bones, as well as keeping other parts of our body healthy.

The recommended daily intake of phosphorus for healthy adults is between 800mg and 1200mg. A balanced nutritious diet provides plenty of phosphorus since it’s found naturally in several foods. Phosphorus is absorbed in the small intestines and stored in the bones; healthy kidneys then discard any extra amounts of this unrequired phosphorus.

Unhealthy kidneys may not be able to remove phosphorus from our blood and can cause critically high phosphorus levels in the blood. This extra phosphorus can cause body changes that pull calcium out of our bones, making them weak and fragile. Moreover, these high phosphorus and calcium levels can then lead to dangerous calcium deposits (calcification) in blood vessels, lungs, eyes and heart. Therefore, phosphorus and calcium control is very
important for our overall health.

A normal phosphorus level for Stage 3 and 4 kidney disease is between 2.7 to 4.6mg/dL and for Stage 5 (dialysis) is between 3.5 to 5.5mg/dL.

Phosphate binders are usually taken WITH or DURING meals and snacks and depending on your (blood) phosphorus level, your appetite, etc—the dose may be individualized. This medication will help control the amount of phosphorus your body absorbs from the foods you eat. It is imperative to take the phosphate binder WITH your meals. When phosphorus is released from food during the digestive process, the binders attach itself to the food like a magnet. In other words, it works like a sponge that soaks up all the phosphorus, thereby preventing it from being absorbed into the blood and maintaining a normal phosphorus level. So, waiting too long (more than 20 to 30 minutes) to take your binders after a meal can delay binding to a great extent.

There are two main types of phosphate binders: those containing calcium, and the non-calcium based ones. They are also available in different forms: pills/ tablets, gel caps and chewable tablets. Ask your doctor and/ or renal dietitian to guide you (if needed); in case one particular phosphate binder does not work well for you.

Besides phosphate binders, here are some basic guidelines to help keep your phosphorus under control:
• Reduce the amount of phosphorus you eat on a daily basis, i.e. between dialysis treatments or in general through the day. Check with your renal dietitian for more help on ‘best food choices’ for a renal and/ or low phosphorus diet.
• Avoid skipping, missing or shortening your dialysis treatments (if applicable): Dialysis treatments remove (some) phosphorus from the blood. So, it is important that you stay for your full-prescribed treatment for best results.
• Take your phosphorus binder with your meals and snacks or as directed by your physician: Phosphorus binders NEED to be taken ALONG WITH most meals and snacks (usually). Binders are like sponges that soak up the phosphorus so if skipped -- the phosphorus enters the bloodstream instead of being soaked by them. Remember, a low phosphorus diet may be necessary for phosphorus binders to work well.

Reference: National Kidney Foundation

Mansi Mehta, RD, LDN, has 10 years experience as a dietitian. She is currently working as a
renal dietitian with Fresenius Medical Care in Chicago.

This article originally appeared in the September 2007 issue of aakpDelicious!.