Most people live normal, healthy lives with one kidney. However, it's important to stay as healthy as possible, and protect the only kidney you have.

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Why do people have a single kidney?

There are three main reasons why a person may have only one kidney:

A person may be born with only one kidney. This condition is called renal agenesis. Another condition, which is called kidney dysplasia, causes a person to be born with two kidneys, but only one of them works. Most people who are born without a kidney (or with only one working kidney) lead normal, healthy lives.

A person may have had one kidney removed during an operation in order to treat an injury or a disease like cancer.

A person may have donated one kidney to a person who needed a kidney transplant.

What if I was born with only one "working" kidney?

In general, most people with a single, healthy kidney have few problems. However, some long term problems have been seen in some people.

In some people who were born with a single kidney, or had a kidney removed during childhood, there is a chance of some slight loss in kidney function later in life. This usually takes 25 years or more to happen. There may also be a chance of having high blood pressure later in life. However, the loss in kidney function is usually very mild, and life span is normal. Most people with one kidney live healthy, normal lives with few problems.

In other words, one healthy kidney can work as well as two.

Can one transplanted kidney work as well as two?

Yes. Testing has shown that a transplanted kidney can also increase in size and function.

How often should someone with one kidney see a doctor?

You should have your kidney function checked at least once a year. Your healthcare provider will check your kidney function by giving you a simple urine test and a simple blood test. You should also have your blood pressure checked every year.

Can a person with one kidney participate in sports?

Physical exercise is healthy and good for you. However, it's important for someone with only one kidney to be careful and protect it from injury. This recommendation applies to anyone with a single kidney, including people who were born with one kidney and people with a kidney transplant. Some doctors think it is best to avoid contact sports like football, boxing, hockey, soccer, martial arts, or wrestling.

Wearing protective gear such as padded vests under clothing can help protect the kidney from injury during sports. This can help lessen the risk, but it won't take away the risk. Talk to your healthcare provider if you (or your child) want to join in contact sports. You should always think about the risks involved in any activity, and carefully consider whether the risks outweigh the benefits.

Will I need to follow a special diet?

Most people with one healthy kidney do not need to follow a special diet. If you have a kidney transplant due to kidney disease or kidney failure, you may have some restrictions. If you have questions about your diet, talk to your healthcare provider or a registered dietitian.

What if I have more questions?

If you have more questions, you should speak to your healthcare provider.

If you would like more information, please contact us.

© 2015 National Kidney Foundation. All rights reserved. This material does not constitute medical advice. It is intended for informational purposes only. Please consult a physician for specific treatment recommendations.