What Are the Side Effects of Living With One Kidney?

Living with a single kidney means having only one functioning kidney. This can result from being born with one (renal agenesis), having one that doesn’t function properly from birth (kidney dysplasia), or surgical removal due to injury, disease, or organ donation. Many individuals lead full and healthy lives with few significant problems.

The Body’s Adaptation

The body adapts remarkably when an individual has only one kidney. The remaining kidney undergoes compensatory hypertrophy, growing larger and increasing its functional capacity. This occurs through increased kidney cell size and accelerated cell division. The remaining kidney works harder, increasing its blood flow and filtering capacity to compensate for the missing organ.

This adaptive response allows the single kidney to filter waste and maintain the body’s fluid and electrolyte balance. It can achieve approximately 70-75% of the total function typically provided by two kidneys. This adjustment helps to normalize the overall glomerular filtration rate (GFR), which measures how well the kidneys are cleaning the blood.

Potential Health Considerations

While most adapt well, living with one kidney can present long-term health considerations. One consideration is a potential, often mild, reduction in overall kidney function (GFR) compared to those with two kidneys. Although the single kidney’s GFR may be lower than that of two kidneys combined, it often remains within a healthy range. This mild reduction in GFR might become more apparent over many years.

There is also a slightly increased chance of developing high blood pressure (hypertension) over time. The kidneys play a role in regulating blood pressure, and a single kidney may experience increased workload, potentially affecting this regulation. Some research suggests this risk can be present from childhood for those born with one kidney.

Another consideration is the development of mild proteinuria, or small amounts of protein in the urine. This can be a sign of increased stress on the kidney’s filtering units. While generally mild, sustained proteinuria can indicate potential kidney damage. Though rare, there is a slightly elevated long-term risk of developing chronic kidney disease (CKD) or end-stage renal disease (ESRD) for some individuals. However, for most otherwise healthy people, these risks are generally low.

Living Well with One Kidney

Those with one kidney can take proactive steps to support their long-term health and minimize potential risks. Regular medical check-ups are important, typically annual visits to a doctor or nephrologist. These appointments allow for monitoring of kidney function through blood tests, such as creatinine and GFR, as well as urine tests to check for protein. Blood pressure should also be routinely monitored, as its control is important for kidney health.

Maintaining adequate hydration is a simple yet effective measure to support kidney function. While a special diet is not usually needed for most people with one healthy kidney, general healthy eating habits are beneficial. This includes a balanced intake of fruits, vegetables, and whole grains, and potentially a moderate protein intake to avoid excessive strain on the kidney. Limiting excessive salt intake is also advised to help manage blood pressure.

Awareness of certain medications that can be harmful to the kidneys is also important. Non-steroidal anti-inflammatory drugs (NSAIDs) should be used sparingly and under medical supervision. Maintaining an active lifestyle is encouraged, but caution is advised with high-impact or contact sports that carry a risk of kidney injury. Wearing protective gear may help, but discussing specific activities with a healthcare provider is recommended. Additionally, avoiding smoking and excessive alcohol consumption supports overall health and kidney wellness.