Depending on the stage of chronic kidney disease, different dietary rules apply. Those who eat and drink accordingly and take sufficient exercise can have a positive influence on the course of the disease and improve their well-being.
Many metabolic processes also depend on the performance of the kidneys: If the kidneys become weaker, the energy and protein metabolism, for example, becomes unbalanced. The salt and water balance of the body is also disturbed. In advanced kidney disease, this leads to serious consequences such as weight loss, hyperacidity and water retention in the organs and tissue.
For people with chronic kidney disease, a number of dietary rules therefore apply. It is often difficult to stick to this “kidney diet”. However, doctors, nutritionists and dieticians can help people to better understand these rules and implement them in their everyday lives. Many people with chronic kidney disease get used to the recommendations over time and use them as a way to do something for their own well-being. An adapted diet and sports also have a positive effect on other diseases and risk factors, such as high blood pressure.
How much can one drink?
Most people with chronic kidney disease can initially drink as much as they want. However, as kidney function progressively deteriorates, many affected people excrete less water. If you then drink too much, you will overhydrate, causing edema to form and blood pressure to rise. Dialysis treatment cannot completely compensate for this, as it can only remove a limited amount of water from the body.
Depending on the type of dialysis and on whether and how much urine the kidneys still excrete, the following recommendations apply: Ideally, you should only drink as little fluid as your kidneys still excrete as urine – plus 0.5 liters a day for hemodialysis or 0.8 liters a day for peritoneal dialysis. Not only drinks, but also liquid foods such as soups, yogurt or compote must be included in the calculation.
In order not to drink too much, it can help to use smaller glasses and cups and, if possible, take the medication with a meal instead of an extra glass of water. If you feel thirsty, you can soothe it with a sour candy, pieces of lemon or sugar-free chewing gum, for example. It is also helpful to drink slowly and avoid dry room air.
Pay attention to a normal weight
If you are chronically ill with kidney disease and at the same time overweight, losing weight can reduce your risk of complications such as heart attack or stroke.
However, in the case of advanced chronic kidney disease, being overweight is rather rare – then there is a greater risk of losing too much weight. To avoid underweight, it is important to eat enough and, above all, to eat properly. Dialysis patients are recommended to eat between 30 and 40 kilocalories per kilogram of normal weight daily. Normal weight is not the person’s current body weight, but the weight that is considered normal according to the Body Mass Index (BMI) according to their height. For a 180 cm tall man, for example, it is around 70 kilograms. This results in a calorie requirement between 2100 and 2800 kilocalories per day.
How much protein is sensible?
People who do not yet need dialysis should not take too much protein, but not too little either. Several studies have shown that a low-protein diet can delay the progression of chronic kidney disease in some people and protect them from complications. Whether other diets can also protect is not yet sufficiently proven by trials. But too little protein is not good enough, because the body would break down muscle protein if there was a protein deficiency.
According to common recommendations, the daily diet should contain about 0.8 to 1 gram of protein per kilogram of normal weight. Therefore, if you weigh around 70 kilograms, it is best to eat around 60 grams of protein per day. For example, a beefsteak (140 grams) contains about 45 grams of protein, a breakfast egg about 13 grams and an apple less than 0.5 grams.
People who have to go on dialysis because of kidney failure, on the other hand, have an increased protein requirement. At least 1.1 grams of protein per kilogram of body weight are then recommended daily, and up to 1.5 grams for peritoneal dialysis. In this case, a lot of protein is lost via the peritoneum into the dialysis fluid.
How much table salt is allowed?
Increased blood pressure and too much protein in the urine can accelerate chronic kidney disease. Studies have shown that a low-salt diet can lower blood pressure and protein excretion. Based on initial study results, experts assume that this also leads to complications such as kidney failure or heart attack less frequently or only later. However, this has yet to be confirmed by long-term studies.
Salt also binds water in the body and increases thirst. For people on dialysis who are not allowed to drink much, it is therefore particularly important to be very sparing with salt.
About 5 to 6 grams of table salt per day are recommended. For classification: A slice of bread contains about 0.5 grams, a Wiener sausage just under 2 grams, and a piece of pizza over 4 grams of table salt. Abstaining from salty foods is often difficult, especially in the beginning. After two to three weeks, however, the sense of taste gets used to less salt. In addition, food can also be prepared with herbs, onions, lemon, vinegar or other spices.
In advanced kidney disease, not only is common salt (sodium chloride) a problem, but the kidneys are also less able to regulate the amount of potassium and especially phosphate. For this reason, dialysis patients should avoid foods containing many of these minerals as far as possible. These include potatoes, bananas, dried fruit, chips, French fries, processed cheese, milk or nuts. Caution is advised with so-called diet salt: It is low in sodium but high in potassium.
How much exercise is good?
Keeping in motion as much as possible is also good for chronic kidney disease: regular exercise can help lower blood pressure, maintain muscle tone and generally feel better.
Experts recommend thirty minutes of light sport five times a week. But even if you can’t manage that, it’s good to get as much exercise as possible. It helps if family and friends support your sports program and you make physical activity a part of your everyday life. Even during a dialysis session, you can do sports and pedal a so-called bed bicycle, for example.