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The Kidneys

A graphic image with a picture of kidneys on it.
Are you at risk of kidney disease? Listen to the podcast to find out how you can tell.

My Amazing Body is a podcast where we explore interesting, unknown and misunderstood parts of your body with help from medical experts and stories from real Queenslanders.

This episode is all about the kidneys. Dr Vishwas Raghunath explains what the kidneys are, how they work and how you can look after your kidneys and lower your risk of developing kidney disease. Queenslander Angela Retchless tells her touching story of living with poorly functioning kidneys, until she received a kidney donation from her father.

Meet our guests

A photo of Dr Vishwas Raghunath

Dr Vishwas Raghunath is a Nephrologist and Obstetric Medicine Physician at Ipswich Hospital.

Angela with her father, who was her kidney transplant donor.

Angela shares her experience of receiving a kidney transplant, donated by her father.

Kidney transplant recipient Angela's twin sons

Episode materials

Audio is great, but some things are best seen as well as heard. These materials provide more information about topics we touch on in the show.

Diagram of the kidney

A diagram showing the parts of the kidney.

Kidney Disease Risk Test

Want to find out your risk of kidney disease? You can find Kidney Australia’s Kidney Disease Risk Test Tool here.

Drinking water and cutting back on salt

In the podcast, Dr Raghunath suggests staying well hydrated by drinking plenty of water and cutting down on salt intake as two key ways to look after your kidneys. You can find more information about these topics at the links below.

Dehydration – the conditions all Queenslanders need to be aware of

6 things you thought you knew about salt that just aren’t true

5 things you can do to look after your kidneys today

Episode transcript

Host: The kidney - one of the few organs that is so important to the health of your body, you've got two of them, just in case something happens to one. If your kidneys stopped functioning properly and you didn't receive treatment fast, you could die. But it's possible to lose up to 90% of kidney function without ever experiencing any symptoms, and Kidney Health Australia estimates that about 1.5 million Aussies are living with chronic kidney disease and don't even know it.

Hi, I'm Elise. Welcome to the latest episode of My Amazing Body, where we explore interesting, unknown and misunderstood parts of your body. Today, we're learning all about the kidneys.

If yours are healthy, in the minute that you've been listening to this podcast, about one litre of blood will have flowed into your kidneys, ready for filtering. But cleaning blood isn't all the kidneys do. They also create urine, help maintain your blood pressure and play a role in promoting your bone health. In this episode, we'll learn all about these different functions of the kidneys, find out what you can do to prevent kidney disease and hear from Angela, a Queensland woman who received a kidney donation from her dad.

We spoke with Dr Vishwas Raghunath, Nephrologist and Obstetric Medicine Physician at Ipswich Hospital, and a major fan of the kidney. He explained all the different ways our kidneys work to keep us alive and well.

Dr Raghunath: Look, the kidneys are essentially a fantastic set of organs. You can sort of think of them as very complex, environmentally-friendly waste disposal system.

Host: First of all, we wanted to know, what do the kidneys look like, and where are they?

Dr Raghunath: Most of us are born with about two kidneys. They're fairly small in size; they weigh about 150 grams which is roughly the size of a baseball. They're kidney-bean shaped as well. They're positioned near the middle of the back on either side of the spine, below the ribs.

Host: The position of your kidneys in your body gives an indication of just how important they are. At the back of your abdomen, your ribs and the thick muscles of your back protects the kidneys from external damage, while perirenal fat surrounds them like an extra protective cushion.

While most of us have the standard two kidneys, it is possible to born with just one, or even with more than two kidneys.

Dr Raghunath: I would say that it's not rare, but it's not that common either, that people are born with probably just one kidneys. And one of the reason is that most of them wouldn't know.

So, most of the times when you don't have a reason to get it checked, you often don't know whether you have one or two kidneys.

Host: Dr Raghunath says people can also be born with extra kidneys, but more commonly, people might have a duplex or duplicate kidney, which means one of the kidney organs has developed with extra blood collecting centres.

Dr Raghunath: What can happen is there can be anatomical variations in the kidneys. They're a very dynamic organ. The way they are when you are a baby in development is very different to how they turn out as an adult.

Host: The kidneys are best known for cleaning blood and turning waste from the blood into urine. They do this through a complex system of veins, arteries, filtering units and waste disposal tubes.

Dr Raghunath: So, the way it works is, yes, in simplistic terms it is a filter. So, you have blood that enters the kidney through the artery, and the artery breaks up into this tiny network of smaller blood vessels called capillaries. And the importance of that is to allow a larger surface area to come into contact with the filter of the kidneys. Now, when that happens and a lot of blood comes into the kidneys, so in fact, when they looked at it they found that the kidney per unit of tissue, the kidney receives more blood than the brain, the liver, or the heart as organs.

Host: Once the blood is in your kidneys, small filtering units called nephrons have the job cleaning out unwanted products.

Dr Raghunath: Now, as I've said, the kidney's not just one large big filter, it's a combination of millions of small little filters called nephrons. Now, these nephrons clean the blood by removing excess salt and waste and hence make urine.

Host: Each day, your kidneys filter the equivalent of about 200 litres of blood.

Dr Raghunath: The kidneys work 24/7. Now, out of these roughly 200 litres, we make about one to two litres of urine. What happens is that the way these filters are designed, they're not passive filters. They're very active filters. So, if accidentally some of the good stuff, that is some good proteins, some good salts, leak into the urine there is a way to actually take them back and reabsorb them and put them into the blood. So, there's a very interesting system of features that works within this filter to help make urine.

Host: Now, we're about to get a little bit personal. What happens in the bathroom-type personal. How familiar are you with your urine? Just like some consider the eyes the windows to your soul, Dr Raghunath says your urine can give you a pretty good view of the day-to-day running of your kidneys.

Dr Raghunath: So, the key question, the key concept here is hydration. And that's something we need to focus on and most people who have interacted with kidney health professionals always remember hydration. It's all about concentrations. So, water is your predominant component. So, if you have a higher concentration of waste products, the urine tends to be a darker colour. If you have lower concentration, it tends to be paler in colour.

So, urine predominantly is water combined with the waste products. Now, most of these waste products are based on things like urea and some excess salt. So, it's always getting rid of excess salt, is what the kidneys normally try and do. The toxins are mainly produced by breakdown of certain essential components of your diet. That is carbohydrates, fats, and proteins. Now, when they get broken down, most of them are absorbed into the body. Which we need for our daily nutrition and growth. And whatever is excess and a by-product is eliminated in the kidneys as waste.

Now, the kidneys work closely with the liver in this regard because the liver manages a different kind of toxins and products which get excreted through the gut. Whereas the kidney takes the water-soluble components and gets rid of them through the urine.

Host: Drinking plenty of water helps your kidneys to work at their best. Most people need about 2-3 litres of water a day, while people who do a lot of exercise or work in hot environments will need even more than that. But you don't necessarily need to measure your water intake by the millilitre. Dr Raghunath says that taking a quick peek at your pee before you flush can tell you how you're going when it comes to hydration and keeping your kidneys happy.

Dr Raghunath: So, we in fact use the urine colour to judge how much water people are consuming, because if you consume good amounts of water you have paler coloured urine. And often I tell my patients to look at their urine colour. Especially on some days like warmer days, or let's say when they're traveling, especially on flights, long-haul flights. They haven't had enough water if they look at their urine and it appears to be darker in colour. That's a sign to drink more water, and if you just drink about a few glasses immediately, and the next time you pass urine you will notice a significant difference in colour.

Host: Dehydration isn't the only condition that can affect what your urine looks like. Other changes, like difference in colour or frothiness, might be a warning sign of kidney disease. If you notice these changes when you go to the bathroom, it's important to let your GP know so they can investigate further.

Dr Raghunath: If you notice frothy urine, it might be sign that there's a lot of protein in the urine. Now, protein in the urine is predominantly made up of albumin. Albumin is the same protein that we find in egg. So, when we whisk egg whites, we get the frothy mixture to make a meringue or in urine when you're whisking it, as in passing urine into a bowl, it becomes frothy. And that's an early important sign that we think about.

Different coloured urine, for example, blood in the urine might appear as either blood clots or just a reddish tinge in the urine, or a bit like Coca-Cola coloured in the urine. It's important to take note of these things. Now, it might be something as common as certain dietary changes and that might affect the colour of the urine. For example, beetroot can colour your urine reddish. Certain vitamins, especially the B vitamins can colour the urine orange. So, it may be that you see certain colours, but it's always important to talk to your doctor about these as well.

Host: Are you ready for this episode's mystery body part? See if you can guess the body part from the clues given. We'll reveal the answer at the end of the episode.

I'm fleshy and made up of a mixture of fat cells and areola tissue. I have really good blood supply, which is useful for keeping me warm. Some people choose to put piercings in me for decoration. Do you know what I am?

You may never wondered exactly why you go to the toilet…it seems simple, what goes in must come out, right? But by filtering blood, your kidneys aren't just creating urine. They're also helping to maintain your blood pressure, working closely with your heart and arteries to keep your circulation system working at its best.

Dr Raghunath: The main ways in which they regulate blood pressure is they handle salt and water in your body. By gauging and getting rid of excess salt and water, they're able to make sure that your blood pressure stays within a certain range. And the reason this happens is that salt holds on to water. So, when salt holds on to water and more of it stays within your blood vessels, it automatically pushes your blood pressure up.

Now, using certain hormones that are generated within the kidney and interacting with the other hormonal systems in the body, they're able to excrete some of this excess salt and water, and hence control blood pressure. In certain situations where you might get dehydrated or you might have a very low salt diet, which is not very common in this day and age, you can have the kidneys trying to conserve or hold on to that salt and water to try and maintain that blood pressure as well. So, it's a very dynamic system that interacts closely with your heart to maintain good blood pressure.

Host: Because balancing your body's salt is one of the main jobs of the kidneys, if you want to help your kidneys out, it's important to not add too much extra salt to your diet. In fact, Dr Raghunath says that ingesting excess salt is one of the biggest risk factors when it comes to developing kidney disease.

Dr Raghunath: From a diet perspective, the biggest culprit is the balance of salts in your body. We live in a society where salt is readily available. Whether it's an obvious form or hidden form. And most of us consume more than the recommended dosage of salt per day. Now, what's the recommended dosage? It's about a teaspoon. And that's all you should be having. But, an average Australian diet has double the normal requirements of the salt. So, it can be tricky to select foods that are low in salt. Not just because of the obvious salt that we add on the table, but also the hidden salt that's there in certain foods such as bread and Weet-Bix, that we may not know about as well.

Host: Would you ever munch down on a teaspoon of salt? Probably not. But over the course of a day, you might actually be consuming far more than that, without even reaching for the salt shaker. How could you cut down on salt in your diet?

If it's not enough for your kidneys to clean out your blood and rid your body of toxins, Dr Raghunath says they also play a vital role in your bone health.

Dr Raghunath: So, that's an important relationship between the kidneys and Vitamin D. Now, as we all know, sunlight plays an essential role in activating Vitamin D. Most of us get our Vitamin D through dietary sources. And when exposed to sunlight, that undergoes an activation process. Now, once the Vitamin D component gets activated under the skin, it then gets transported to the liver and the kidneys for further activation. There's a three-step process involved. Now, the tissue of the kidneys are responsible for that last step of activation. Which you can almost think of as being the most crucial step. Because if the kidneys don't make the final product, then you don't have the Vitamin D available for their normal day to day function. Vitamin D, as we know, is very essential for bone health.

Host: 1 in 10 Australians, or 1.7 million people, have signs of chronic kidney disease. But what is kidney disease? Does everyone who gets it need to go on dialysis? Can you prevent the development of kidney disease? Dr Raghunath helped us understand the condition and why it's often called a "silent killer".

Dr Raghunath: The kidneys, as we all know, mostly start healthy and over a period of time can get damaged. There is an age-related damage, because of wear and tear that happens as we all grow older, but also the way the kidneys can get damaged could be really slow. Which is termed chronic damage, or Chronic Kidney Disease. And then there's something that can be very rapid, called acute damage, or Acute Kidney Disease. And these are terms that people might often hear or read about, in reports with regards to kidney disease.

Host: Kidney disease happens when the kidneys stop working properly and aren't able to filter the blood as efficiently as before. The kidneys are really good at compensating for damage - even if you completely lost one whole kidney, your other kidney would pick up the slack. That means that many people with kidney disease won't have any signs that something's wrong until the disease has significantly progressed.

Dr Raghunath: One of the issues is that kidney disease is often termed as a silent disease. The reason is that you could lose 90% of your kidney function and not have many symptoms. And that's remarkable, because that means that most people won't know that they have kidney disease. This in fact has been looked at in great detail and we have looked across the nation in Australia, and we think that one in 10 individuals have some form of kidney disease.

Host: So, what signs and symptoms should Queenslanders be looking out for when it comes to their kidney health?

Dr Raghunath: Often when you get to very severe degrees of kidney damage is when the symptoms start coming to light. Now, the problem then again, is that some of these symptoms are fairly vague. It could be as simple as tiredness or fatigue. It could be as simple as puffy legs, which some people can attribute to the weather, or travel. Or it could be as simple as nausea and reduced appetite, which people attribute to other illnesses. So, it is really difficult in some instances to pick up on kidney disease. Often the message is, if you have some of these that persist, go see your doctor. Because they may be indicators of kidney disease.

Host: As Dr Raghunath mentioned earlier, other warning signs of kidney disease include discoloured, bloody or frothy urine.

But what if you don't have any signs of kidney disease? Should you just assume that your kidneys are fine?

Dr Raghunath: I think the first point is being aware. And I think just being aware of the fact that kidney disease in its complexity exists, it's already a step in the right direction. And, the next step would be to try and take control over how you can manage your risk. Everyone's risk is different for kidney disease, as it is many other health conditions in the world. So, when you look at your own risk profile, based on some of the factors that I previously mentioned, you can then take the next step to perform a kidney health check.

Host: All different factors, from your age and family history, to whether you have conditions like diabetes or high blood pressure, as well as your lifestyle, can affect your risk of kidney disease. You can take a Kidney Risk Test on the Kidney Health Australia website, to find out what your risk level for kidney disease is - we'll have a link to this in our show notes. If you have any risk factors, Dr Raghunath recommends talking to your GP about having a simple test called a kidney health check.

Dr Raghunath: Now, the kidney health check is a simple process. All it involves is checking a urine. And the reason we check the urine is for protein leakage, which could be a marker for kidney disease. And a blood test. The blood test will determine something called the Estimated Glomerular Filtration Rate, which is a bit of a tongue-twister, but it's simplified as eGFR. Now, this is another phrase that you would have heard your doctors use many a times. And this refers to the percentage, so the function of the kidneys at this stage. So, these are the two main components of the kidney health check. This is used very closely with watching your blood pressure, which as I said is one of the commoner causes of kidney disease, and the three of them together are a good tool to identify your risk.

Host: Queensland woman Angela is more familiar with her kidneys than most people. When she was a child, it became clear that there was something not quite right with her kidneys and how they were working.

Angela: I was getting a lot of UTIs, infections, just vomiting a lot from memory, and just feeling pretty awful, so obviously they took me to the doctor, and they did some tests, and then I do remember being at the RBH, and them saying that I've got high blood pressure, and my kidneys don't work properly.

Host: Angela has a reflux condition that affects her kidneys, which means that urine sitting in the bladder can travel back up the ureter and into her kidneys. She says her condition had a pretty big impact on how she lived her life.

Angela: I've really tried to not let it define me, I suppose, or interrupt things that I do, but I guess some of the negatives were, I liked playing a lot of sports, and due to blood pressure and stuff like that, and having to stay hydrated, they don't want you doing too much, just with little athletics and that sort of thing, I had to be really careful.

But as an adult more so, when I met my husband, we were very second-guessing, "Should we get married? Should we buy a house? Am I going to have to stop work at some stage?"

Host: While her kidney function slowly declined, Angela's doctors prepared her for treatments she would eventually need to save her life.

Angela: When I first went to clinic they were very much, "We are happy with a slow decline." There was never a, "It will get better," or "We can stop it in its tracks," stuff like that.

Kidney transplant, kidney failure, dialysis, all that sort of stuff, it's always just, it just lingers in the background I suppose.

Host: As she reached her early thirties, Angela's kidney health was significantly impacting her life. She had to carefully schedule everything she did to conserve energy, and she and her husband Luke decided to put starting a family on hold.

Angela: Sometimes my breath would smell funny, my skin would change colour, but mostly fatigue. Again, with Luke, my husband, we wouldn't go out on Sundays, because you've got to be fresh for the working week. We wouldn't go out during the week. You'd sort of only might go out one night a weekend, or just stuff like that really, where you had to really prepare yourself for whatever you had coming up. You couldn't really sort of just fly off to, go to parties or dinners or breakfasts. Couldn't go to dinner, and then go to breakfast sort of thing. It was a lot of planning.

And then, of course, having babies, something we probably would've done a lot earlier.

My nephrologist explained it to me that I would be able to fall pregnant, and probably carry, but wasn't really strong enough to sustain both of us, and I would end up on dialysis, and you don't really know the outcome for either the mother or the child.

Host: In 2013, Angela was told she was either going to need to start dialysis or receive a kidney transplant.

Angela: It was just, I guess the doctors asked the question more than anything, "Is there anybody would donate a kidney for you?"

Host: Angela's father and brother both volunteered their kidneys for her transplant, and because he was a close match, her father was chosen to be her donor.

Angela: He and my brother started the workup, and dad was the closest match, because I think parents can be a better match than siblings, because obviously you get half from each parent. It was like a five out of six. I don't know, it's very technical. It's all that stuff, but a five out of six, a very good match, and apparently mum and dad have the same heritage. We're all Irish, so it made an even better match, I think.

It's like, is it the only major surgery you get with no medical benefit? He goes in, he's receiving no benefit, but accepting all the risk, really. Pretty amazing.

Host: Both Angela and her father recovered well from their surgeries, and Angela makes sure they mark the anniversary of the operation together every year.

Angela: Amazing. What do you say? "Thank you"? Like it's not enough.

We just try and spend the day together every year. We see each other all the time, because he lives around the corner, but we just try and have that day. We go to lunch or whatever. Just something.

Host: With a new kidney, Angela noticed an instant difference in her health and quality of life. Gone were the days of over-scheduling and feeling unwell - now she could live life just like an ordinary person.

Angela: Amazing. Truly amazing. Because it's a chronic disease, and it just, you know, can go on and on forever, you don't really know how you feel until you feel something different. It was almost instant, pretty much, from waking up. You just felt so much energy, so alive, it was amazing. You think, "Wow, this is what people feel like all the time."

There was no planning. You could just do stuff. We can just go out whenever we want. It truly was just instant.

People ask me that all the time. "Did it change your life? Really?"

Because outwardly, probably, I'm just the same, and they don't see the planning, so to speak, and all that sort of stuff. I went back to work, and they're like, "You've been away for a while."

They thought I was pregnant, because I was still a bit swollen, and I said, "No, no. I had a kidney transplant." And they just were like, "Oh my God, I'm so sorry." I'm like, "Don't apologise. It's the best thing that could ever happen."

Host: Angela's swelling subsided, but her abdomen didn't quite look the same as before. Unless there's a need to, surgeons won't remove the faulty kidney being replaced in the transplant and will instead place the new kidney at the front of the abdomen. This meant that Angela could actually see the outline of her new gift.

Angela: You can see it a lot of the time. If I lay flat, say after the transplant, you could see a little, it's actually quite big, I think it's 11 centimetres or something maybe, and pretty substantial. It's at the front, in the pelvic area. There's not a heap of room there, I suppose. If you lay down, you can see a bit of a bump there.

Host: Five years on, and Angela and her kidney are doing well. She still has to take a lot of medication to support the donation, but she's enjoying her new, healthy life. In the best news of all, a couple of years ago she and Luke were surprised with a twin pregnancy. Now, when she looks at her happy, healthy two-and-a-half-year-old boys, she sees the legacy of her father's donation.

Angela: Organ donation is amazing. It doesn't just change peoples' lives, it saves their lives. It creates life, you know, with my boys.

Host: Now that she's living with a functioning kidney, Angela encourages other Queenslanders to look after their kidneys, too.

Angela: They just do so much more than you could ever imagine. Drink lots of water, don't smoke, have a drink but don't drink in excess, stay hydrated, that sort of thing is the most important.

Host: For pictures of Angela and her thriving family, more information about preventing kidney disease or information about signing up as an organ donor, visit the show notes for this episode on our website.

Thanks for joining us for another episode of My Amazing Body. Did you enjoy this episode? If you liked it, please leave a rating or review in your podcast app.

Before we go, did you guess the mystery body part for this episode? The warm, fleshy tissue that you might have pierced are your earlobes! Congratulations if you got it right.

My Amazing Body is brought to you by Queensland Health. With special thanks to our expert guest Dr Vishwas Raghunath, kidney donation recipient Angela, and my podcast colleagues - Lauren our researcher, writer and producer, Carol our audio technician, Helen on sound effects and Dan our Music Guru. Special thanks to the media team at West Moreton Hospital and Health Services and the team at Donate Life.

Last updated: 6 January 2020