April 10, 2025, 3:30 pm | Read time: 7 minutes
They filter waste products from the blood, form urine, and regulate blood pressure: our kidneys perform important tasks. This is how we can ensure that they are healthy — and prevent diseases.
They are located at the back of the abdomen, at the level of the lower ribs, and their shape is reminiscent of kidney beans: We are talking about our kidneys, our body’s sewage treatment plants. The kidneys produce urine and ensure that our body excretes waste products. But what happens when this no longer works as it should? Unfortunately, kidney disease comes on gradually and usually causes no symptoms at first. Read here to find out how to keep your kidneys fit and healthy — and how to recognize when something is wrong.
Overview
What Function Do the Kidneys Have in the Body?
Quite a lot! The kidneys are paired and bean-shaped. They are located in the lumbar region of the body. For their size, they are particularly well supplied with blood. Their most important function is to filter the blood. In doing so, they cleanse the blood of waste products that are excreted in the urine. The formation of urine also regulates the water and electrolyte balance. Electrolyte balance refers to the distribution of potassium, magnesium, sodium, calcium, phosphorus, and chloride in the body.
The kidneys also play a role in the regulation of blood pressure and are necessary for blood formation. They produce the hormone erythropoietin, which stimulates the production of erythrocytes. They also secrete the enzyme renin, which helps regulate blood pressure and salt balance. The kidneys are also necessary for the production of vitamin D.1
Biggest Risk Factor for Kidney Disease
Diabetes is a common cause of kidney damage, according to the Association of Diabetes Consultants and Trainers (VDBD).2 Diabetics should, therefore, have their kidneys — specifically the blood values UACR and eGFR — checked by a doctor at least once a year. This helps to detect diseases at an early stage.
What We Can Do Ourselves for Healthy Kidneys
If something is wrong with the kidneys, the whole body can become unbalanced. In chronic kidney disease, the kidneys no longer work as well. People with chronic kidney disease have an increased risk of cardiovascular disease and acute kidney disease. However, if you only pay attention to symptoms, you will probably only recognize kidney disease at a very late stage. That’s why it applies to everyone: To prevent it from going that far, it’s worth paying attention to your kidneys. Six things are important here:
1. Regular Visits to Your GP
Creatinine levels in the blood or protein in the urine play a role in assessing kidney health. A urine test strip can show whether protein has been excreted or whether there is blood in the urine. The GP can also take a blood sample and determine the blood creatinine level in the laboratory. This value provides an indication of how well the kidneys are performing their filtration function. An elevated value can be the first sign that kidney function is declining.
2. Eat a Balanced and Low-Salt Diet
In addition to diabetes, high blood pressure is also a risk factor for kidney disease. If you consume a lot of salt in the long term, you risk high blood pressure — which puts a strain on the kidneys. The German Nutrition Society (DGE) recommends consuming a maximum of six grams of table salt per day.3 This amount corresponds to about one teaspoon. The recommendation of the World Health Organization (WHO) is even lower: a maximum of five grams a day, children only two grams a day.4
How can you switch to less salt? The best way is to proceed step by step. After all, a preference for salty foods is a matter of habit. If we gradually reduce the amount of salt, we will miss the taste less over time.
Because processed foods such as bread, sausages, cheese, and ready-made products contain a lot of salt, it is also worth taking a comparative look at the nutritional value tables, according to the consumer advice center. It is best to cook your own meals and focus on vegetables, pulses, and healthy fats. Salt should only be added sparingly, instead fresh herbs or a squeeze of lemon juice add zest to your food. A Mediterranean diet, preferably low in meat, is top for kidney health.
3. Bring Exercise into Your Everyday Life
At least 150 minutes of moderate exercise per week has a positive effect on metabolism and kidney function. The VDBD cites walking, cycling, and swimming as examples.
It also becomes easier if you increase your daily exercise. For example, the German Kidney Foundation suggests always taking the stairs instead of the elevator or walking across the room during long phone calls. You can also extend walking distances by parking a little further away or getting off the bus one stop earlier.
4. Reduce Body Fat if You Are Overweight
As mentioned, diabetes is the biggest risk factor for later kidney disease. People of normal weight have a lower risk of developing diabetes — and, therefore, also kidney disease.
If you include lots of vegetables in your diet and get plenty of exercise, you are doing something to reduce any excess weight. This is also good for the kidneys. Too much body fat promotes inflammatory reactions and high blood pressure. Both put a strain on the kidneys, according to the VDBD.
5. Give Up Smoking
Smoking also affects the kidneys: Nicotine plays a major role in vascular diseases — and these are closely linked to kidney disease. Smoking is considered a risk factor for kidney cancer — more than 5,000 people die from it in Germany every year.5 So, giving up cigarettes — and, if possible, passive smoking — is also worthwhile for the kidneys.
If you want to finally make a start on quitting smoking, you can call the Federal Institute of Public Health (BIÖG) for free advice (0800 8313131).
6. Avoid Heavy Alcohol Consumption
Many people are aware of the link between alcohol and liver disease. However, heavy alcohol consumption can also damage the kidneys — both directly and indirectly, because alcohol alters the fluid balance and liver function. So, if you want to keep your kidneys fit, you should avoid it.
7. Do Not Take Certain Painkillers in Large Quantities
Genetic factors or autoimmune diseases can also promote kidney disease. However, taking painkillers such as ibuprofen or diclofenac can also trigger kidney disease — at least if you take them in very large quantities.
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How Does a Damaged Kidney Manifest Itself?
In chronic kidney disease, the kidneys no longer work as well. To assess this, creatinine is measured in the blood, and the estimated glomerular filtration rate, or eGFR for short, is determined. The classification ranges from “normal” to “kidney failure”.
As already mentioned, kidney damage in the early stages is usually asymptomatic. Physical symptoms only occur at later stages, although the frequency can vary from person to person. According to the guidelines for the care of patients with chronic kidney disease issued by the German Society for General Practice and Family Medicine, these include:
- Fatigue or weakness
- Anaemia
- Difficulty concentrating
- Sleep disorders
- Kidney failure 6
Your GP can assess your personal risk of kidney disease by carrying out a laboratory test on your blood and urine. People with chronic kidney disease have an increased risk of cardiovascular disease and acute kidney disease.
*With material from dpa