A low-phosphate diet can help you stay fit if you have kidney disease. However, in addition to your diet, taking the right phosphate binders can also play an important role in keeping the phosphate levels in your blood in balance. In this article you will find an overview of the availbale phosphate binders used in chronic renal insufficiency.
Phosphate in the human body
Phosphate is one of the most important minerals in your body. Together with calcium, it is primarily responsible for the stability and structure of bones and the regulation of the balance between bone formation and bone resorption. At the same time, phosphate is an important component of energy metabolism and is responsible for building genetic material.
In a healthy person, a deficiency of phosphate usually results in more phosphate being absorbed from the intestines. The excess is then filtered out and excreted by the kidneys. In the case of kidney disease (=CKD), this regulation no longer functions properly. This often leads to phosphate accumulating and being deposited in the blood and body. For this reason, the body needs some support in regulating the phosphate balance. In the following sections you will learn how exactly you can support your body in regulation the phosphate balance.
Target values for phosphate in kidney disease
If the phosphate level is too high, phosphate forms a compound with calcium and is deposited in unwanted places in your body. These include the walls of blood vessels, for example. This condition is called hyperphosphatemia. Consequences of this can include bone loss, calcification of the blood vessels, or calcium deposits in the soft tissues around the joints.
Calcified vessels can also make it harder for the transplant surgeon to connect a new kidney to the body's blood vessels. So it's worth it to keep a close eye on your phosphate levels.
But what exactly should your phosphate level be now if you have kidney disease? As a guideline, don't exceed 1.45 mmol/l (or 4.5 mg/dl) of phosphate in your blood. The phosphate value also changes relatively slowly and is rarely subject to rapid fluctuations. As such, it often takes a while until your phosphate levels react to a therapy. Therefore, be patient if you do not see immediate results and always discuss the procedure with your medical team!
How do I lower my phosphate levels?
So now you know which target value your phosphate values should optimally reach. But what can you do now specifically to reduce these values? You should be able to lower your phosphate value by:
- Following a low-phosphate diet
- Efficient dialysis (if required)
- A proper intake of phosphate binders if they have been prescribed to you by your medical team
A phosphate-reduced diet is important to keep your phosphate levels in balance. Eating a low-phosphate diet can be a bit of a challenge, especially in the beginning. Your body still needs energy and the right amount of protein to work well. But don't worry, you're not on your own. In the Mizu App you will find many tools, tips & tricks to make such a low phosphate diet easier for you in your daily life. Your nephrologist can also help you with questions on this topic. You will see: Even if the change in diet is somewhat challenging at first, it will become easier over time.
Depending on the duration and procedure, an average of 2,400 to 3,000 mg of phosphate is removed from the blood each week during dialysis. While this is a tremendous help to your body, it is usually much less than the amount of phosphate you consume through food. The reason is that much of the phosphate is not stored in the blood. Dialysis does remove all the phosphate from the blood and new phosphate subsequently migrates back into your blood to compensate for the imbalance that has occurred.
For this reason, a phosphate-reduced diet and regular dialysis alone are not enough. By following the third point - the correct intake of phosphate binders, if prescribed by your doctors - you can also help your body to prevent the phosphate from being absorbed in the first place. Let's now take a closer look at which phosphate binders are available and how they work exactly.
Various forms of phosphate binders
Phosphate binders - as the name suggests - bind phosphate in your body and cause you to excrete it more or not absorb it in the first place. However, there is not only one type of phosphate binder. Many different forms of phosphate binders exist. Below you will find below an overview of common varieties of phosphate binders and and which active ingredients they contain so that you do not lose track of the many names:
- Calcium-containing phosphate binders (e.g. Calcium acetate)
- Combination preparations of calcium carbonate and magnesium carbonate
- Aluminum-containing phosphate binders
- Magnesium-containing phosphate binders
- Calcium- and aluminum-free phosphate binders (e.g. sevelamer, lanthanum carbonate)
Modes of action of phosphate binders
Phosphate binders are usually taken as tablets with meals. They bind the phosphate contained in your food in your gastrointestinal tract and ensure that it is not absorbed into your body in the first place.
It is therefore important that the phosphate binders are taken directly at the beginning of a meal, unless otherwise discussed. The dose depends on the amount of phosphate your meal contains. To better estimate phosphate amounts, you can also consult the phosphate points in the nutrition section of the Mizu app. Logically, a meal high in phosphate will require more phosphate binders than a meal low in phosphate.
But be careful - phosphate binders can sometimes prevent other medications like antibiotics, iron, or immunosuppressants from being absorbed into your body. So always discuss the intake of your phosphate binders with your doctor. As a rule, a time interval of about 30 minutes from other medications should be observed. Phosphate binders are now also available in the form of granules, gels or powders. If you have any problems, you can consult your medical team and switch to another form of administration if necessary.
Side effects of phosphate binders
Side effects can also occur when taking phosphate binders. For this reason, it is important that you consult your doctor as soon as you feel unwell.
Taking phosphate binders that contain calcium can lower your phosphate. However, they can also raise your calcium level. For this reason, your blood levels should be checked at regular intervals so that you can react to changes early on. They can also cause bloating, a feeling of fullness or diarrhea.
Phosphate binders containing aluminum can lead to aluminum deposits or constipation. They should therefore generally not be taken over a very long period of time and, if possible, should not be used in childhood. Phosphate binders containing magnesium can also cause digestive problems. Calcium- and aluminum-free variants can also cause a feeling of pressure or pain in the abdomen.
If you experience side effects, it is best to talk to your doctor. By adjusting your medication or changing the preparation, these can often be controlled and brought under control.
So you see that - if already necessary - regular dialysis and a phosphate-reduced diet are important building blocks to keep your phosphate levels in balance. Taking the right phosphate binders can also help the body to absorb less phosphate from food. If you have questions or experience side effects, contact your doctor. Your treating team will be happy to help you with any uncertainties and support you in the therapy best possible!
Medical Note: This article is for educational and knowledge purposes only. This article is in no way intended to recommend, evaluate, or promote any specific class of medication. If you have any questions about taking any medication, you should always contact your medical team.
