Most people are born with two kidneys, but the human body adapts remarkably well. The straightforward answer is yes, a person can survive with only one kidney, and most individuals with a single functioning kidney live full, healthy lives. These bean-shaped organs are located just below the rib cage on either side of the spine. They are responsible for filtering the entire blood supply multiple times a day, and the remaining organ is typically able to handle the body’s needs.
Essential Functions of the Kidneys
The kidneys perform several functions that maintain the body’s internal stability. Their primary task involves filtering the blood to remove waste products like urea and other toxins generated from metabolic processes. They process approximately 120 to 150 quarts of blood daily, producing one to two quarts of urine composed of waste and excess fluid.
Beyond waste removal, the kidneys regulate the balance of water and electrolytes, such as sodium, potassium, and calcium, necessary for proper nerve and muscle function. They also help maintain the body’s acid-base balance by controlling the excretion of hydrogen ions. This regulation of fluid and chemical levels ensures that cells throughout the body can operate correctly.
The kidneys also act as endocrine organs, producing hormones that influence distant body systems. They release the enzyme renin, which helps regulate blood pressure. Another hormone produced is erythropoietin, which stimulates the bone marrow to produce red blood cells responsible for carrying oxygen throughout the body.
The Body’s Adaptation to Single Kidney Function
When a person loses a kidney, whether through donation, surgical removal (nephrectomy), or being born with a single kidney (renal agenesis), the remaining kidney begins a process of physiological change. This adaptation is known as compensatory hypertrophy, where the remaining organ increases in size and mass. The enlargement occurs through an increase in the size of the kidney’s filtering units, the nephrons, and their associated tubules.
To compensate for the loss, the single kidney’s nephrons increase their filtration rate, a process called hyperfiltration. This means each nephron works harder, filtering a greater volume of plasma than it did previously. This adaptive mechanism is effective, allowing the single kidney to take on a significantly larger workload.
The result of this adaptation is that the single kidney can restore the total filtration capacity to a level reaching 70 to 75% of the original function of two kidneys. This recovery is sufficient to prevent the buildup of toxins and maintain internal balance. The increased workload necessitates careful long-term management.
Long-Term Health and Monitoring
Living with one kidney requires a proactive approach to prevent undue stress on the sole functioning organ. Regular medical monitoring is recommended, typically involving annual check-ups to assess kidney function and overall health. These check-ups include checking blood pressure, as hypertension is a common risk factor for kidney damage.
Monitoring Kidney Performance
Specific laboratory tests track the kidney’s performance. A blood test measures creatinine levels, a waste product that increases as kidney function declines. Doctors use the creatinine result to estimate the Glomerular Filtration Rate (GFR), which measures how well the kidney is filtering waste. A urine test is also conducted to check for the presence of protein, specifically the albumin-to-creatinine ratio (ACR), which can indicate early kidney damage.
Lifestyle choices play a significant part in safeguarding the single kidney’s health. Maintaining adequate hydration is important to help the kidney flush out waste efficiently. Dietary adjustments include limiting sodium intake to help manage blood pressure and moderating protein consumption, as excessive protein can increase the kidney’s workload.
Individuals with a single kidney should avoid certain over-the-counter medications. This particularly includes the long-term or excessive use of non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, which can harm kidney function. It is also advisable to avoid high-impact contact sports, such as football or boxing, to protect the remaining kidney from traumatic injury.