Kidney scientist

About your kidneys

What do your kidneys do?

They do a lot! Your kidneys clean your blood, getting rid of waste water and waste products in the form of urine (pee). Your kidneys make sure that you have the right amount of water and salts to keep your body working properly. If you drink a lot, they will get rid of the extra water and if your body needs to hold onto water when you are not well, or on a very hot day, the kidneys make sure that this happens. If your kidneys stop working, waste products and water will build up in your blood and you can get very sick.

Your kidneys help your body to produce red bloods cells, they produce hormones to keep your bones healthy; they also help to control your blood pressure.

How do your kidneys clean your blood?

Each kidney is connected to two big blood vessels, the renal artery brings the dirty blood in, and the renal vein takes the cleaned blood away. Inside the kidney there are thousands and thousands of tiny blood vessels that filters and clean your blood and make urine.

This filtering system cleans your blood hundreds of times a day. The waste products are washed out as urine that collects in a space in the middle of your kidney called the renal pelvis. The urine then drains down a tube called the ureter to your bladder. When there’s enough urine in your bladder you get the urge to go to the toilet. You pee the urine out through a tube called the urethra.

Kidney disease

Kidney disease can go on for a long time without you noticing. If you’re at risk of kidney disease, you need to know what it is and how to prevent it.

  • Kidney disease damages the tiny blood vessels in your kidneys so they don’t do their job properly.
  • Kidney disease usually affects both kidneys and may also damage other parts of your body, such as your heart.
  • When enough of the blood vessels are damaged, your kidneys stop working and your body will fill up with excess wastes and water. This can happen when you have kidney disease for a long period of time.
  • If your kidneys stop working, you must have either dialysis or a kidney transplant.

You’re more likely to have kidney disease if you:

  • Have high blood pressure
  • Have diabetes
  • Smoke
  • Have a family history of kidney disease
  • Are over 50
  • Are of Māori or Pacific heritage

Most kidney disease doesn’t cause any symptoms until the late stages, so if you’re in any of these groups, ask your doctor for a kidney check-up. If you find you have kidney disease early enough, there are things you can do to help slow down or prevent further damage.

To protect your kidneys:

  • Keep high blood pressure under control – usually with medication
  • Keep your blood sugar under control if you have diabetes
  • Avoid dehydration
  • Avoid medications that could damage your kidneys, such as those containing ibuprofen or diclofenac

If your kidneys stop working

If your kidneys have stopped working, you have 3 treatment options:

Dialysis booklet


Dialysis takes over the job of filtering and cleaning your blood.

If your kidneys have stopped working, you must stay on dialysis for the rest of your life, unless you can get a new kidney.

While dialysis takes time and effort, and is not as easy or as good as having healthy kidneys, it still does a pretty good job to help people live a normal life.

You can read more about dialysis in the booklet Treatment options for Chronic Kidney Disease (CKD).

Kidney transplant booklet

Kidney transplant

A kidney transplant is an operation to have someone else’s healthy kidney put inside your body. If the transplant works well, you’ll no longer need dialysis.

For most people having a kidney transplant is the best treatment.

You can learn more from the booklet: Having a Kidney Transplant

Conservative treatment booklet

Conservative treatment

Some people decide to have ‘conservative’ treatment (also called palliative or supportive care) rather than dialysis or a transplant – particularly if they have other serious health problems.

Conservative treatment includes medical, emotional, social, spiritual and practical care for both you and your family/whānau.

You can learn more by reading the booklet: Conservative Treatment


If you’re at risk of developing kidney disease, making lifestyle changes such as losing weight, getting some regular exercise, stopping smoking, eating less salt and drinking less alcohol can help you avoid getting it.

If you have high blood pressure

Talk to your doctor about what your blood pressure should be and what you can do to keep it at a safe level.

  • You may need to make some lifestyle changes to reduce your blood pressure.
  • Your doctor may prescribe medication to control your blood pressure.

If you have diabetes

If you have diabetes, good blood pressure and blood sugar control are very important to reduce the risk of kidney damage.

  • Have a kidney check at least once a year. This will include a blood test, urine test and a check of your blood pressure. Get your doctor to explain the results
  • Keep good control of your blood sugar levels, to help slow kidney damage
  • Make healthy food choices. It’s important to follow the eating plan given to you by your dietician or health professional
  • Avoid becoming dehydrated, especially when you’re sick
  • Make sure you do some regular activity (walking is good)
  • Only drink small amounts of alcohol
  • Control your blood cholesterol levels with diet and medication as needed
  • Don’t take non-steroidal anti-inflammatories like ibuprofen or diclofenac
  • Treat urinary infections immediately

Living with Kidney Disease

Chronic kidney disease is not usually curable. The good news is that if you find out about it early enough, you can help slow down or even stop it from getting worse. Lifestyle changes such as exercising more, losing weight, eating less salt, drinking less alcohol and quitting smoking can help.