|Useful links: Life with a single kidney and How to look after your kidneys
We can live quite well with only one kidney and some people live a healthy life even though born with one missing. But while bones can break, muscles can waste away and the brain can sleep without risk to life, if both of your kidneys fail, as happens in end stage kidney failure, bone, muscle or brain can not carry on.
How do our kidneys work?
Think of your kidneys as an extremely sophisticated, waste disposal system, which sorts non-recyclable waste from recyclable waste, 24 hours a day, 7 days a week, while also cleaning your blood. Much of this waste is produced by the body as it processes the food you eat.
Most people are born with two kidneys, each one about the size of an adult fist, are bean-shaped and weigh around 150 grams each. The kidneys are located at both sides of your backbone just under the rib cage or above the small of your back. They are protected from injury by a large padding of fat, your lower ribs and several muscles.
What do your kidneys do?
Our kidneys are small biological marvels with a fascinating design. Healthy kidneys act like a filter to make sure the right amount of wastes and fluids are removed. Every hour your blood supply circulates through the kidneys about 12 times. Each day your kidneys process around 200 litres of blood, with around 1 to 2 litres of waste leaving the body as urine.
Our kidneys make three important hormones, erythropoietin, renin and active vitamin D. Erythropoietin stimulates the production of red blood cells, renin is involved in the control of blood pressure and active vitamin D controls calcium uptake and helps make strong bones.
Our video collections of videos on YouTube, which have been grouped into playlists, to learn more about the kidneys and the urinary system and other related topics. Start with the video below and later you can view a wide range of reviewed kidney health education videos on our profile KidneyHealthAus - on YouTube.
Without any kidney function our body dies. Some kidney function is essential for life!
What is the role of your kidneys in keeping you healthy?
For organs so small, your kidneys works hard - they have a number of vital roles to play in the daily functions of our body, as they:
- act as filters for your body to clean blood of wastes, yet retain essential elements needed by the body
- they keep the proper balance of salts and acids in the body, and produce hormones and enzymes which help to:
- control your blood pressure
- help to keep your internal water balance
- make red blood cells and help maintain your blood composition and pH levels
- maintain strong and healthy bones and help to keep mineral balance
Your kidneys are master chemists of the body, intervene in many processes and balances in the body and control many vital body functions. The major role of the kidneys is to remove waste from the blood and eliminate it in the urine. To remove this waste and extra water, blood enters the kidney through the renal artery; blood is then cleaned in the kidney as it passes through tiny filters called nephrons.
The nephrons are the basic working units of the kidneys, controlling the formation of urine. One kidney contains about one million nephrons, and each nephron contains a filtering apparatus called a glomerulus.
Inside each kidney there are about one million tiny units called nephrons which filter blood as it passes through each nephron and water and waste products are removed. Most of the water returns to the blood, the waste products collect in the bladder then leave the body as urine (wee). Image from DaVita
Anatomy of the kidneys
We have about a million hairpin-like glomeruli at birth, but lose about 100,000 of these every decade of life. Droplets of filtered blood pass through a number of tubules (tiny tubes) into the medulla, a central collecting region. The glomeruli and tubules together make up nephrons, long and extremely fine tubes which, if connected, would run for 80 kilometres (50 miles).
Cleaned blood returns to the body by the renal vein. Waste and extra water removed by the kidney passes through a tube called the ureter to the bladder, where it is stored as urine or wee. When the bladder is full, urine passes out of the body through another tube called the urethra.
The process of removing waste and extra water in simple terms is:
- food and drink enters the stomach and are broken down into nutrients
- solid waste products are removed and nutrients enter the bloodstream.
- nutrients are used by the body for energy, growth, repair and maintenance of body functions.
- this process creates waste which is removed by the kidneys.
- extra nutrients not immediately needed by the body are also removed by the kidneys.
- waste products and extra water move from the kidneys to the bladder, then leave the body as urine
The kidneys are designed to last a life-time. They do an amazing job! It is important to care for them.
We recommend these kidney education tools below for a visual introduction to the kidney
Click on each diagram to view animated presentations on how our kidneys work and how dialysis works to replace the work of healthy kidneys.
Kidney Health Australia acknowledges the generosity of DaVita (USA) for allowing us to use these images and host their excellent teaching resource (flash animation) on our website.
WHAT CAN GO WRONG WITH THE KIDNEYS?
Most kidney diseases attack the nephrons. Sometimes kidney failure can happen quickly, caused for example by a sudden loss of large amounts of blood or an accident. A sudden drop in kidney function is called Acute Kidney Failure and is often short lived, but can occasionally lead to lasting kidney damage.
More often kidney function worsens over a number of years.This is actually good news, because if kidney disease is found early, medication, dietary and lifestyle changes can increase the life of your kidneys and keep you feeling your best for as long as possible.
Kidney disease progression can also be slowed with medicines which help to protect your kidneys. Your GP can prescribe these medicines for you. Talk to your local pharmacist when you have your prescription filled.
Take the test at Check My Kidneys to find out if you are at increased risk of kidney disease
What does Chronic Kidney Disease mean?
If you lose over 1/3 of your kidney function for over 3 months, it is called Chronic Kidney Disease or CKD.
Sometimes kidney disease leads to kidney failure, which requires dialysis or a kidney transplant to keep you alive. Early detection and treatment can help prevent kidney failure and the need for dialysis or transplant treatment.
If you are diagnosed with CKD, this means that your kidneys have been damaged and are not working as well as they should normally. Kidney disease is called a ‘silent disease’ as there are often no warnings.
- It is not uncommon for people to lose up to 90% of their kidney function before getting any symptoms.
- People can live a near normal life with as little as 20 percent of their total kidney function.
- When symptoms do occur the initial signs may be general, such as feeling tired or generalised itching.
- As kidney disease progresses, symptoms can include changes in the urine (reduced volume, discolouration, blood or pus), nausea and vomiting and appetite loss.
- Other symptoms include swollen or numb hands and feet (because of water retention), weakness and lethargy, darkened skin and muscle cramps.
- About 50 people a day die of a kidney related disease.
How do you know if you have CKD?
In most cases CKD does not cause any symptoms and is detected because a test has shown an abnormality. It may be a urine test for blood or protein; an X-ray or scan of the kidneys; or a blood test to measure kidney function. Most cases are discovered by your GP as part of normal care.
How common is CKD?
1 in 9 Australians over age 25 years have at least one clinical sign of existing CKD, such as reduced kidney function or evidence of kidney damage. It is less common in young adults.
In the older person it is more common due to the natural aging of the kidneys. A number of diseases can damage the kidneys such as diabetes, hypertension (high blood pressure) and some inherited conditions.
Almost all of these will damage both kidneys at the same time.
Go to our Fast Facts on CKD page for statistics
Useful links: Kidney Disease: Are you one in three?
KHA Kidney Health Resources including simplified translated versions
KHA pages: Your heart and CKD and Diabetes and CKD
If concerned your medication may be affecting your health refer to ABC Health Consumer Guides or check with Medicines Line 1300 MEDICINE (1300 633 424) for independent pharmacist advice on prescriptions, over-the-counter, and complementary (herbal / natural / vitamin / mineral) medicines.
Urinary tract infections (also known as UTIs)
A UTI should be treated promptly as a kidney infection is serious. It is important to see a doctor if a kidney infection or kidney stones are suspected because lasting damage or even kidney failure can occur if these conditions are left untreated. Infection which has spread from cystitis or pyelonephritis can be life threatening.
What can I do to keep my kidneys healthy?
Key recommendations to staying healthy and maintaining kidneys health are:
- Keep your blood pressure below 130/90 and maintain healthy levels of cholesterol
- If you have diabetes make sure you actively treat your blood glucose levels - normal levels are 4-6 mmol/L before meals and 4-8 mmol/L two-hours after meals.
- It’s important to have your cholesterol levels checked regularly - the recommended level is no higher than 5.5 mmol/litres
- Lead a healthy lifestyle and maintain healthy weight, be active for more than 30 minutes most days
- Eat a balanced healthy diet low in saturated fats
- Become a non smoker
The food you eat plays a huge role in the health and well being of your body. As well as providing the body with a variety of nutrients, food choices can also help in weight reduction and weight control.
- eat healthy foods - with as many fresh ingredients as possible.
- don't over eat - always leave a meal feeling like you could eat a little bit more.
- eat breakfast - a good breakfast activates your metabolism first thing in the morning.
- avoid fad diets - they are hard to maintain over a long period and can create or worsen ill health.
- check nutrition panels on all parcelled foods you buy - choose only foods that list a low percentage of sugar and salt and are low in saturated fats - find out about food ingredients.
To satisfy thirst - drink water instead!
Drink plenty of fluids and listen to your thirst. Water is the recommended choice, it is also calorie-free, inexpensive and readily available. Sugar drinks have lots of calories, while caffeine and alcohol are both diuretics and can leave the body dehydrated.
Research also states that one drink containing sugar each day, has been shown in females to be associated with an 80 % increase in the risk of acquiring diabetes. Choose to drink water instead!
Note: Bottled mineral water contains salt which can lead to fluid retention and even increased blood pressure in susceptible people. Check the label and choose low sodium varieties (less than 30mg sodium per 100ml).
Losing weight can reduce how hard your kidneys need to work
Weight loss can also lead to a decrease in the amount of protein lost via urine. High levels of protein in the urine can make your kidney function worse. Obesity may also cause some people with existing forms of some kidney disease to loose their kidney function more rapidly.
There is also evidence to suggest excess weight is also associated with an increased risk of kidney cancer. If you are overweight, you have an increased risk of developing diabetes and high blood pressure - both are major risk factors for kidney disease. Losing as little as 5 kilograms reduces blood pressure in most people who are 10% above a healthy weight.
Do at least 30 minutes of physical activity most days of the week
Stay fit. The key is to start slowly and gradually increase time and intensity of activities. Physical activity leads to increased strength, stamina and energy. You can break down any activity into 3 x 10 minute bursts, which can be increased as fitness improves.
STOP exercising without delay, tell your health care team, or go to hospital if you: - have chest pain or pressure
- feel dizzy or light headed
- have an irregular or fast heart beat that persists when the activity is completed
- have excessive shortness of breath
Useful weblink: Measure Up and CKD for tips on a healthy life
Be or remain a non-smoker
It is well known smoking harms your health and greatly increases your risk of developing many chronic conditions. Smoking causes narrowing of the arteries, including small vessels that are in the filter in sections of your kidney, and reduces the ability of the kidneys to work properly. Smoking has been linked to cancer of the kidneys, the bladder and ureter (the small tubes that run from your kidneys to the bladder). The message is clear: don't smoke. If you do smoke, giving up is one of the best things you can do to keep your kidneys healthier. Order a free QUIT pack - call the QUIT Hotline 137 848
Don't drink too much alcohol
Be smart about your alcohol intake. While some studies show alcohol causes no harm to the kidneys, it may be dangerous if you already have kidney problems. Alcohol makes your kidney produce more urine than normal, and excessive drinking can have a negative impact on other parts of the body that may contribute to kidney damage, such as the liver. To avoid dehydration caused by more frequent urination, ensure you alternate between alcoholic and non-alcoholic drinks. A glass of water is of course the ideal choice here.
There have been studies that have shown that heavy drinking may contribute to high blood pressure and heart disease, which over time may contribute to kidney disease. Alcohol has a high sugar content and therefore may lead to weight gain, another risk factor for kidney disease.
- How many alcoholic drinks can you have without it affecting your kidneys?
There is evidence to suggest that one standard drink for women and the elderly (e.g.100ml wine; 285ml full strength beer; 30 ml spirit) or two standard drinks for men, three to four times a week, may have a positive health effect.
Useful link: Australian guidelines to reduce health risks from drinking alcohol
Quick links: Fact Sheets> - Recommended weblinks - Organ Donation
Page updated 25 February 2014
Disclaimer: Information provided is intended as an introduction to this topic and not meant to substitute for your doctor's or health professional's advice. All care is taken to ensure this information is relevant and applicable to each Australian state. Kidney Health Australia recognises each person's experience is individual and variations do occur in treatment and management due to personal circumstances. Consult a healthcare professional for specific treatment recommendations.