This filter protects your body

What are the main functions of the kidneys?

The kidneys are the body's purification plants. They are bean-shaped, weigh about 150 grams each and lie to the left and right of the spine under the diaphragm. In the centre of each kidney is the renal hilum (renal gate). This passageway accommodates lymphatic and blood vessels, nerves and ureters and is key to vital processes. The renal artery carries blood containing waste products to the kidney for cleansing, while the renal vein returns the cleaned blood to the systemic circulation. Urine finally reaches the bladder via the ureter.

The central role of the kidneys becomes clear when you consider that they filter the entire blood volume of a person—about five to six litres—around three hundred times every day. This vital task of detoxifying the blood and finely regulating fluid and electrolyte balance often happens out of sight, but it is the foundation for a healthy and balanced functioning of our body.

The kidneys also perform other vital and varied tasks that ensure the body functions properly. These include the regulation of blood pressure and the acid–base balance, i.e. the blood pH. In addition, the kidneys are heavily involved in hormone production (renin, erythropoietin) and the activation of vitamin D.

They carry out essential tasks such as removing toxins from the blood, regulating fluid and electrolyte balance, and producing hormones.

They filter the entire blood volume several times a day and are critical for regulating blood pressure and acid–base balance. Without functioning kidneys, the body would be unable to remove toxins and recover important substances.

How does the kidney filtration process work and what role does it play for health?

On the path from blood to urine, two crucial 'wash cycles' occur. In the first step, large amounts of primary urine are filtered from the blood plasma every day. In the second step, most of the fluid and all vital substances are reabsorbed from the primary urine. Only then is the remaining fluid excreted as urine into the bladder. This interplay makes the kidneys masters of blood purification and substance recovery. A disruption of this process can lead to serious health problems.

Which symptoms and causes can indicate impaired kidney function?

Because the kidneys have many jobs, impaired kidney function can lead to a wide range of different and serious effects. Unexplained itching anywhere on the body, an unpleasant odour of the urine, fluid retention in tissues (edema) and possibly general symptoms such as difficulty concentrating and nausea can all indicate suboptimal kidney function and the risk of kidney failure, including chronic kidney disease. The noticeable symptoms are due to insufficient elimination of toxic metabolic products by the kidneys.

The causes of chronic kidney disease can be diverse, including pre-existing conditions such as high blood pressure, diabetes mellitus and various kidney disorders. With increasing age, the kidneys may lose performance and become more susceptible to disease, often without being noticed.

Older people often tend to drink less, which can lead to dehydration. Adequate fluid intake is however crucial to maintain kidney function and to ensure effective flushing of the organs. Dehydration in combination with certain chronic diseases also promotes the formation of kidney stones. These can obstruct the urinary tract and cause back pressure. As a result, the kidneys are stressed and their function impaired.

Which laboratory values help diagnose kidney disease?

To assess kidney function, various renal laboratory values are measured. Key parameters include creatinine, creatinine clearance, cystatin C, urea, residual nitrogen and the glomerular filtration rate (GFR).

Creatinine is a breakdown product of muscle metabolism and is excreted by the kidneys. Elevated creatinine levels in the blood indicate reduced kidney function, but alone are not sufficient to make a definitive assessment.

Creatinine clearance compares creatinine concentrations in blood plasma and urine to better evaluate kidney function.

Cystatin C, a protein produced by all cells, is cleared by glomerular filtration; an elevated value generally indicates impaired kidney function.

Urea and residual nitrogen from protein breakdown are elevated in the blood when kidney function is reduced.

The glomerular filtration rate (GFR) indicates how much of a substance is filtered by the kidneys per unit of time and takes into account parameters such as creatinine and inulin clearance. GFR can vary and is influenced by factors such as age, height and weight.

What effects does kidney disease have on the body?

Severe, untreated urinary tract infections can damage the kidneys. Autoimmune diseases, such as systemic lupus erythematosus and IgA nephropathy, can also cause the immune system to attack the kidneys and damage them. Diseases affecting the blood vessels, such as vasculitis, can impair renal perfusion and cause kidney injury. If such a condition is suspected, a doctor should be consulted.

The kidneys work closely with other organs, particularly the heart. Heart disease can impair healthy kidneys, while kidney disease can in turn negatively affect heart health. This is no coincidence: a healthy heart ensures optimal renal perfusion, which in turn is vital for heart function. Kidney damage can burden the heart and vice versa. As already mentioned, they play

How to keep your kidneys healthy as long as possible: tips and tricks

• Make sure you drink enough to ensure effective flushing of the kidneys. Prefer water and herbal teas. Also make use of the benefits of naturopathic kidney teas.
• Many medications can impair kidney function, so they should be used with care and not taken lightly.
• For nutrition, it is recommended to reduce table salt intake and to avoid unhealthy fats where possible. Avoid long-term diets with excessive protein content, as they can be a burden on the kidneys. If you already have kidney insufficiency, follow general dietary recommendations for kidney patients, particularly reduced intake of protein, phosphate, potassium and salt.
• Several scientific studies have shown that pectin in apples can protect kidneys from stone formation. It helps lower blood lipids and cholesterol, can assist with weight loss, detoxifies the body and has a positive effect on blood pressure.
• Scientific research has shown that consumption of buckwheat, thanks to its lecithin content, has positive effects on kidney health. A particular benefit of this pseudo-cereal is that it is gluten-free, so people with celiac disease can safely consume buckwheat.
• Lemon has the ability, through its citrates, to bind excess calcium in the kidneys. Since kidney stones are largely composed of this mineral, regular consumption of lemons, whether as water or a smoothie, can help prevent stone formation.
• Vegetables from the cruciferous family such as cauliflower, broccoli, kohlrabi, white cabbage, Brussels sprouts or Chinese cabbage are foods that positively affect the kidneys. They are rich in healthy nutrients such as iron, calcium, selenium, copper, manganese and zinc as well as so-called glucosinolates. According to a large meta-study, these glucosinolates can measurably reduce the risk of renal cell carcinoma and therefore kidney cancer.
• Olive oil helps protect the kidneys. The oleic acid it contains has preventive effects against high blood pressure, which benefits the kidneys. The oil of this Mediterranean fruit also has positive health effects, including for breast cancer, heart disease, diabetes and depression. It is therefore advisable to occasionally flavour dishes with high-quality olive oil.
• Cocoa beans contain flavonoids, a group of water-soluble plant pigments. These can reduce oxidative stress and improve vascular function. The latter contributes to optimal kidney function. An occasional piece of chocolate with a high cocoa content is therefore worthwhile.
• Ginger has been shown to have positive effects on a variety of ailments, including sprains, high blood pressure, digestive problems and cramps. The ginger root also has positive effects on the kidneys. The antioxidants in ginger, with their anti-inflammatory properties, may help in treating kidney damage, according to studies.
• Monitor your blood sugar carefully! The long-term blood sugar value (HbA1c) should be below 7 percent in diabetics, and even lower in young, otherwise healthy people.
• Watch your blood pressure – high blood pressure is a risk factor for developing kidney damage. It is therefore important to check blood pressure regularly and treat it if necessary. The same applies to elevated blood lipid levels: talk to your doctor about appropriate medication for you.
• A mindful approach to stress, regular preventive check-ups, quitting smoking and moderate alcohol consumption also help maintain kidney health.
• Special yoga exercises for the kidneys combine breathing techniques and movement. Certain twisting movements gently massage the internal organs. In a healthy body, this stimulates circulation and can improve kidney function.
• Incorporate regular physical activity into your daily routine. Even small activities positively affect circulation and kidney health. For example, stay in bed five minutes longer after getting up to raise your legs and simulate cycling movements while lying down. Avoid using the lift or escalator at the office or in the mall and take the stairs instead. A short walk after work is also recommended.

Give your kidneys the best care by eating a healthy and varied diet, exercising regularly and avoiding stress. A balanced lifestyle is the key to optimal kidney health!