It is generally possible to survive and live a healthy life with only one kidney. The human body is remarkably adaptable, and one kidney can often perform the work of two. For most people, having a single kidney does not significantly impact life expectancy or quality of life.
How the Body Adjusts
When an individual has only one kidney, the remaining organ undergoes a process known as compensatory hypertrophy. This adaptation involves the single kidney increasing in size and functional capacity to handle the body’s filtration needs. The kidney’s cells grow larger, enhancing its ability to filter waste products from the blood.
The remaining kidney also increases its glomerular filtration rate (GFR), which is the rate at which fluid is filtered from the blood into the kidney’s filtering units. This elevated GFR helps maintain the overall efficiency of waste removal and fluid balance in the body. Kidneys possess significant reserve capacity, performing functions even with reduced filtering capability.
This compensatory mechanism allows the single kidney to take on the workload typically managed by two. In some cases, the solitary kidney can achieve a filtration capacity that is up to 70-85% of what two healthy kidneys would normally provide.
Causes of Having One Kidney
Individuals may have a single kidney for several reasons, including congenital conditions, surgical removal, or kidney donation. Some people are born with only one kidney, a condition known as renal agenesis, where one kidney fails to develop during fetal growth. Unilateral renal agenesis occurs in approximately 1 in 1,000 to 2,000 births.
Another congenital cause is kidney dysplasia, where a person is born with two kidneys but only one is functional. Beyond birth, surgical removal of a kidney, known as a nephrectomy, is a common reason. This procedure might be necessary to treat kidney cancer, severe injury, chronic infection, or other diseases that damage the kidney beyond repair.
A significant number of people also live with one kidney after donating one for transplantation to a family member, friend, or even a stranger. Kidney donation is a carefully considered process, ensuring the donor’s remaining kidney is healthy and capable of compensating.
Living Well with a Single Kidney
For individuals living with a single kidney, consistent medical oversight is important for long-term health. Regular annual medical check-ups are recommended to monitor kidney function. These check-ups often include blood tests to measure creatinine and estimated glomerular filtration rate (eGFR), indicating kidney filtration. Urine tests for proteinuria (protein in urine) and albumin-to-creatinine ratio are also performed to detect early signs of kidney damage.
Controlling blood pressure is a key factor in protecting the remaining kidney. High blood pressure can put additional strain on the kidney, potentially leading to further damage.
Adequate hydration is important to support kidney function, as water aids filtration and maintains blood vessel health. Healthy adults with one kidney should aim for about 2.5 liters of fluid daily, adjusted for activity and climate. Water is the best choice, but other fluids like unsweetened juices also contribute.
Medication awareness is important, as some drugs, such as nonsteroidal anti-inflammatory drugs (NSAIDs), can stress the kidney. Consulting a doctor before taking new medications protects kidney health.
Regarding lifestyle, avoiding activities with a high risk of blunt abdominal trauma, such as certain contact sports, is sometimes advised, though the risk of serious kidney injury from sports is low. A balanced diet is sufficient. Avoiding excessively high protein intake (above 1.0-1.2 grams per kilogram of body weight per day) is also recommended to prevent undue strain on the single kidney.