Most people know that the kidneys purify the blood. Who does not know the stories of people whose kidneys function so badly that they have to ‘on dialysis’ (artificial kidney) or need a kidney transplant to keep their blood clean? But the kidneys, two bean-shaped organs of about 12 centimeters in size that lie at the waist level against the inside of the back, do more than remove waste products from the body: they also produce hormones (for example to regulate blood pressure and to increase red blood cells). and keep the moisture balance of the body in balance.

miraculous

Kidneys have, you might say, a wonderful adaptability. If they don’t work optimally, you usually don’t notice it at all: you don’t get acute problems with the fluid balance, the blood pressure doesn’t get upset, your blood isn’t acutely poisoned. And one step further: if someone misses a kidney – for example because he has donated a kidney as a donor – the remaining kidney usually adapts in such a way that it functions for two.

But despite that adaptability, less well-functioning kidneys are definitely something to worry about. Kidney damage once done cannot be repaired, and it is not always possible to prevent further damage to the kidneys. If the kidneys are only working for 5 to 10 percent, radical treatment such as dialysis or transplantation is required. To reassure you, kidney function never deteriorates dramatically within months. It usually takes years or even decades for incipient kidney damage to develop into truly impaired kidney function.

Physical complaints

Kidney damage is first noticed by protein loss in the urine. In medical terms this is called ‘albuminuria’, where ‘albumin’ stands for protein. A little protein in the urine is normal, namely up to 20 milligrams per liter of urine. If the protein content rises to a maximum of 300 milligrams per litre, this is called ‘microalbuminuria’, which is an indication of starting kidney damage. Microalbuminuria has not yet been detected in the blood.

More advanced kidney damage can be detected in both the urine and the blood. The protein content in the urine then rises to above 300 milligrams per litre, and an increased concentration of the substance creatinine can be demonstrated in the blood. That’s called macroalbuminuria. More than 70,000 adult Dutch people have macroalbuminuria, and three quarters of them are not aware of it. At this stage, the blood pressure can also become somewhat elevated, and the first physical symptoms can begin: fatigue, itching, nausea, no desire to eat, muscle cramps, and dehydration or fluid retention. In other words: in microalbuminuria the kidneys still manage to do their job, in macroalbuminuria the kidney damage is often too advanced for that.

The good news

The kidneys can be affected by a congenital disease or abnormality of the kidneys, but also by abnormalities of the urinary tract, diabetes or high blood pressure. But we also partly control the functioning of the kidneys ourselves: our Western lifestyle does the kidneys no good. Eating too much and too fat, and too little exercise, lead to atherosclerosis, which in turn has a harmful influence on the functioning of the kidneys. High blood pressure can also damage the kidneys, and malfunctioning kidneys increase blood pressure again, in short, the two reinforce each other.

The good news is, of course, that you can do something yourself to keep your kidneys in good shape. Healthy eating and sufficient exercise are extra important if the kidneys are already affected. If the doctor has diagnosed macroalbuminuria, he often prescribes a protein- and salt-restricted diet to limit the damage as much as possible. Whether medication is needed depends on the cause of the protein loss. High blood pressure can be controlled with medication, and diabetes or inflammation can also be treated in such a way that further kidney damage is limited.