As a person on dialysis, you should restrict your phosphate intake to avoid secondary diseases. Have you always wondered what phosphate and dialysis are all about? Here you can learn more about it.
The role of phosphate in your body
Phosphate is important in our body in various places. Together with calcium, it is responsible for a functioning bone metabolism. Simply put, this means that it regulates the balance between bone formation and bone breakdown. It ensures that your bones stay fit. But phosphate is also an important building block for your energy metabolism and for your genetic material in the body.
When a person with functioning kidneys has too little phosphate in their body, phosphate from food is absorbed in the intestines. The excess is filtered out by the kidneys and excreted. If the kidneys are no longer working, this regulation does not happen adequately. While dialysis can reduce blood phosphate levels, current dialysis therapies and the treatment times are unfortunately not sufficient. That's why your dialysis team is always on you about managing your phosphate.
Why is it so important that phosphate is in the target range?
Elevated phosphate levels in the body bind calcium from your bones. Phosphate and calcium then jointly deposit on the walls of blood vessels. An elevated level of phosphate in the blood is called hyperphosphatemia. Over time, this gradually causes a special type of osteoporosis and arteriosclerosis. In other words, too much phosphate in the body 'softens the bones'. The bones decalcify and become brittle, while blood- and nerve vessels calcify. This means that phosphate or calcium deposits are building up in the blood vessels. You can think of this as the blood vessels becoming narrower. As a result, your blood can't flow well through the body. This can lead to various problems, even life-threatening ones. Therefore, it is very important to keep your phosphate levels within a target range. Vessels with very prominent deposits of calcium phosphate can also make it difficult for the surgeon to connect a graft kidney to your blood vessels.
What is the approximate target value for phosphate?
As a guideline for dialysis patients, blood phosphate levels should be adjusted toward the 1.45 mmol/l (or 4.5 mg/dl) reference range. Also important to know: Your phosphate level changes rather slowly in your body. In order for phosphate to fluctuate quickly, you would have to consume a lot of phosphate at once.
How can I keep phosphate under control?
Phosphate management in dialysis patients consists of three pillars:
-
A good dialysis
-
A phosphate-reduced diet
-
The correct use of phosphate binders
1. A good dialysis
As mentioned, dialysis does not manage to sufficiently remove the phosphate in your body in its currently available methods. In fact, dialysis treatment can only remove 2,500 to 3,500 mg of serum phosphate per week from your body, depending on the duration and procedure. However, this is unfortunately much less than a usual weekly amount of phosphate that you take in through food. Phosphate cannot be adequately removed by available dialysis procedures, because of phosphate reservoirs outside of the blood. Through HD and PD, phosphate is only removed from the blood. This is relatively fast, because after only 2.5 hours it is out. However, in response, phosphate from other parts of the body shifts into the blood and the phosphate level in the blood rises again shortly thereafter. Longer dialysis can therefore remove phosphate a little bit better. As you see, the bottom line is that dialysis alone is unfortunately not enough to regulate phosphate in your body.
2. A phosphate-reduced diet
Since dialysis alone is not effective enough, you will be advised to follow a phosphate-reduced diet if your phosphate levels are too high. This means that you should make sure that you eat foods with lower phosphate content. It can be a bit of a challenge, especially in the beginning, to eat a diet that is low in phosphate but still high in protein. Your body still needs a lot of energy and protein to function properly. In the Mizu app you will find many tools, tips & tricks to make such a phosphate-reduced diet easier for you in everyday life.
3. The right intake of phosphate binders
The third pillar of phosphate management is medication - so-called phosphate binders. There are different phosphate binders, all of which work in slightly different ways. Phosphate binders cause the phosphate you eat to be bound directly in your intestines and excreted right away. Phosphate binders have to be taken in combination with a meal and, ideally, in the right dosage. This is not so easy at first, because you need to know how much phosphate is in the food you eat. Your doctor will choose the most suitable phosphate binder for you over time.
What foods contain phosphate?
Phosphate is found in many foods. For example, many meats and cheeses are high in phosphate - some more and some less. You should be especially wary of processed foods and convenience foods, as many of these products are packed with additives. Some of these additives are true phosphate bombs. You can find out exactly how much phosphate is in everything by using the Mizu app. It contains thousands of texts, foods and recipes and interprets them directly for your dialysis requirements.
How much phosphate can I consume?
For people on dialysis, a daily intake of 800 to 1000 mg per day may be recommended. This range could be seen as a starting point for your phosphate-conscious diet. How much phosphate per day balances a protein-rich and healthy diet, good quality of life, and blood phosphate levels for your body is best discussed with your nephrologist and your nephrology dietitian (and your stomach). You can then also store your daily guideline value in the Mizu app and update it at any time. This way you can personalize the app for yourself.
Do I sense that something is wrong with my phosphate?
Too much phosphate in the body rarely leads to immediate symptoms. Over time, noticeable consequences are occlusion or narrowing of your arteries, resulting in insufficient blood flow to the affected areas of the body. The death of some of your skin tissue - necrosis - can also occur.
