Most people probably realise their kidneys are essential organs. But some may be hard pressed to explain why. Many of us may be affected by kidney problems, including three million people in the UK who are estimated to have chronic kidney disease (i) – according to the NHS, this includes one in five men and one in four women between the ages of 65 and 74 (ii). Yet experts believe awareness and understanding of the kidneys is low. This could mean up to a million people have a kidney problem without realising it (iii).
What do your kidneys do and where are they?
Most of us, however, know that we have two kidneys, each of which is about 10 - 15cm long and weighs about 160g. They sit just below the rib cage, one either side of the spine. And while most people have two, it is possible to live a normal healthy life with just one kidney. Sometimes people are born with three kidneys – though this happens rarely (iv).
Your kidneys work hard – they’re thought to use a quarter of the body’s energy – and perform several functions, including removing waste products from the body as urine. Indeed, together, both kidneys filter around 200 litres of fluid every day, producing up to one and a half litres of urine, with all of your blood passing through your kidneys about 40 times every 24 hours.
Not only do the kidneys act as filters for removing waste and toxic products, they also reabsorb the substances your body needs, including vitamins, hormones, amino acids and glucose, returning these back into your bloodstream.
Other vital functions carried out by your kidneys include:
Balancing body fluids and substances called electrolytes (including sodium and potassium)
Producing hormones (including hormones that help maintain normal blood pressure)
Modifying vitamin D to produce an activated form that can be used by the body
Controlling the production of red blood cells
What are the signs of kidney problems?
If there’s a problem with your kidneys, it can make you feel quite unwell. When your kidneys aren’t working properly, it means that waste products (including harmful toxins) and fluids may be building up in your body. This can make you feel tired all the time, and you may have lots of headaches and swelling in your hands, feet and face. You may also put on weight, feel breathless and suffer from pain in your lower back (near your kidneys). Having kidneys that aren’t functioning properly can also increase your blood pressure and eventually cause anaemia and bone disease.
According to the NHS, the main kidney complaints are infections, kidney stones, kidney cancer, kidney disease and acute kidney injury (AKI).
How do you get a kidney infection?
NHS figures suggest one in every 830 people develops a kidney infection each year in the UK, making them a relatively rare occurrence (v). If you’re a woman you’re more likely to have a kidney infection than a man (six times more likely, in fact), thanks to the fact that in women the urethra – the tube that carries urine out of the body – is shorter than that in men (v).
This is because kidney infections are caused by bacteria getting into the urethra and travelling up through the bladder and into the kidneys. Cystitis is also caused by bacteria getting into the urethra and travelling up to the bladder. Indeed, most kidney infections are thought to develop as a complication of cystitis.
Having frequent sex increases the chances of getting a kidney infection, so younger women who are sexually active are thought to be most at risk. Younger children who are born with an abnormality of the urinary tract are also susceptible to kidney infections, as are those born with a condition called vesico-ureteric reflux (where the urine flows back up to the kidneys from the bladder).
What are the symptoms of a kidney infection?
If you have a kidney infection, the symptoms will usually develop quickly, usually in a few hours or so. These include:
Pain in the side of your lower back (where a kidney is located) or around your genitals
High temperature and feeling shivery
Nausea, vomiting and/or diarrhoea
Blood in your urine
Frequent urination and/or pain when urinating
Weakness and fatigue
Loss of appetite
If you experience one or more of these symptoms, see your GP as soon as possible. If a kidney infection is left untreated, it can progress to permanent kidney damage. If caught early, most kidney infections can be treated at home with antibiotics and painkillers.
What causes kidney stones?
Unlike kidney infections, kidney stones (nephrolithiasis) are fairly common, affecting three in 20 men and up to two in 20 women at some stage in their lifetime (vi). They are thought to mostly affect people between the ages of 30 and 60, and often affect people who don’t drink enough fluids or those who take certain types of medication or have certain medical conditions.
Others who may be more likely to develop kidney stones on a regular basis are those who have a family history of kidney stones, those who only have one functioning kidney, those who have had several kidney or urinary infections, those who have had intestinal surgery, and those who are inactive or bed bound, or who eat a high-protein, low-fibre diet.
The stones start out as crystals that form inside the kidneys, made from chemicals in the blood such as calcium, ammonia, cysteine and uric acid. If they aren’t passed out naturally through urine, these crystals can grow into harder lumps.
What are the symptoms?
Once a kidney stone starts to be passed out through the body through the urinary system, it can cause a blockage. This can cause the following:
Severe and sometimes intense pain in the lower back, abdomen and/or groin
Blood in your urine
Pain during urination
The need to urinate more frequently than usual.
Having a kidney stone can also cause a kidney infection.
If your GP thinks you have a small kidney stone that will be passed out in your urine, you may need an injection to help with the pain and a prescription for painkillers to take at home. However, if it’s causing severe pain – or if it’s too big to be passed naturally – you’ll usually need hospital treatment.
What causes kidney cancer?
During the last 10 years, the number of people in the UK diagnosed with kidney cancer has risen by almost a third, making it the seventh most common cancer in adults in this country (vii). Also called renal cancer, it most commonly affects people over the age of 60.
According to the NHS the most common type of kidney cancer is renal cell carcinoma (viii). Experts still don’t know what causes it, but there are several things that could increase your risk of developing this type of kidney cancer, including being obese (that is, if your body mass index is 30 or higher), having high blood pressure, smoking, having a family history of kidney cancer and having certain genetic conditions. If you’ve been having dialysis to treat kidney disease for a long time, it could also make you more susceptible to kidney cancer.
What causes kidney cancer?
Kidney cancer can often be treated successfully if it’s diagnosed early. The problem is, many people don’t have any obvious symptoms early on. And if you do experience symptoms, they can often be mistaken for the symptoms of a urinary tract infection or kidney stones, such as blood in your urine. You may also have pain in your side or lower back, or you may feel very tired and have no appetite. Sometimes you may also notice a lump or swelling in your side – though kidney cancer lumps are often too small to be noticeable.
Kidney cancer is often picked up during tests for other conditions. How it’s treated will depend on its size and whether or not the cancer has spread.
For more information about kidney cancer, visit Cancer Research UK’s website.
Chronic kidney disease
According to the charity Kidney Research UK, one in eight people will develop chronic kidney disease (also called kidney disease) (ix). The name is a general term for when your kidneys simply aren’t working as well as they should. Your risk of having chronic kidney disease increases as you get older, and it’s also more common in black people and those of south Asian descent.
There are several causes of chronic kidney disease, some of which include having high blood pressure, high cholesterol, diabetes and kidney infections. Those who have recurrent kidney stones may also go on to develop chronic kidney disease, as well as people taking certain medicines (non-steroidal anti-inflammatory drugs – or NSAIDs – are one example).
Most people with chronic kidney disease, says the NHS, have a mild form of the disease. But no matter how mild, it can increase your risk of things like heart disease and stroke. However, those who develop more serious problems can develop kidney failure.
What are the symptoms?
Like kidney cancer, chronic kidney disease often has no symptoms during the early stages, and it’s often picked up during tests for other conditions. Symptoms that can appear during the later stages include fatigue, nausea, blood in your urine, shortness of breath and swollen ankles, feet or hands.
Treatments for chronic kidney disease can stop it progressing as well as provide symptom relief. These include lifestyle changes and medication to manage some of the related health problems of chronic kidney disease, such as high blood pressure. People with kidney failure are treated with dialysis – a procedure that involves a machine doing some of the work your kidney would normally be doing, such as filtering your blood) – and, for those with advanced chronic kidney disease, a kidney transplant.
What is acute kidney injury?
This condition is common as a complication of another acute illness, says the National Institute for Health and Care Excellence (NICE), and is thought to affect more than 15 per cent of people admitted to hospital (x) ). It happens when your kidneys are damaged suddenly, which means they don’t work as they should. Some cases of acute kidney injury can be mild, with a minor loss of kidney function, whereas others lead to kidney failure.
Age is one of the main risk factors for acute kidney injury, though children can also be affected. You may also be more likely to develop it if you have a long-term disease such as diabetes, if you already have a kidney problem, if you’re suffering from dehydration, if you have a blockage in your urinary tract or if you have a severe infection. Medicines that can increase your risk of acute kidney injury include NSAIDs and certain blood pressure drugs.
What are the symptoms?
Again, early symptoms aren’t usually apparent, though some people may notice they’re urinating less frequently (or producing less urine). Symptoms can, however, start quite quickly and you may feel suddenly very unwell. If this happens, your symptoms may include nausea, vomiting, abdominal pain, backache, dehydration, high blood pressure and oedema (where fluid builds up in the body and causes swelling).
Treatment varies according to what’s causing the condition and how severe it is. For instance, if it’s caused by an underlying long-term condition, treating the problem will usually treat the acute kidney injury. In severe cases, hospital treatment may be necessary.
How can I improve my kidney function?
Looking after your kidneys can go a long way towards keeping them healthy and free from disease. Here are some of the things you could do:
Stay active: Having an active lifestyle can reduce some of the preventable things that can lead to kidney problems, such as high blood pressure and obesity. Aim to do at least 150 minutes of moderate aerobic activity each week (such as brisk walking or cycling), as well as strength exercises that work all the body’s major muscles on two or more days a week.
What is the best thing to drink for your kidneys?: If you don’t drink enough fluids, your kidneys may not work properly. It’s difficult to say exactly how much you should drink, as what’s right for one person may not be right for someone else (though the Eatwell Guide suggests adults drink six to eight glasses of fluid each day). The colour of your urine is a good way to tell whether or not you’re properly hydrated – if it’s darker than a light straw colour, it’s a sign you need to drink more.
Also remember to drink more than usual when the weather’s hot or when you’re doing lots of exercise.
Watch your weight: Having a healthy body mass index (BMI) of between 18.5 and 24.9 means you may be less likely to develop conditions that affect your kidneys, such as diabetes and high blood pressure.
You can calculate your BMI yourself or ask your GP to do it. Alternatively you can use the online NHS BMI healthy weight calculator. Find out more about managing your weight by clicking here.
Manage your blood pressure: High blood pressure is one of the most common causes of kidney problems. However, as it rarely has any symptoms, in most cases the only way to tell if your blood pressure is high is to have regular blood pressure checks (ask at your local GP’s surgery about free tests). There are lots things you can do to help keep your blood pressure healthy – read all about it by clicking here.
Keep an eye on your blood sugar: If you have diabetes, you have a higher-than-average risk of developing kidney damage. This is one of the reasons it’s important to keep your blood sugar levels under control. It’s also essential to have regular kidney function tests to make sure your condition isn’t having an impact on your kidneys.
Kidneys and smoking: Smoking could affect your kidneys indirectly because it increases your risk for having high blood pressure. It also increases your risk of kidney cancer.
If you’re struggling with withdrawal symptoms while giving up smoking, products that could help tame your cravings – such as nicotine patches, gum and lozenges – are widely available over the counter. Click here for more details about giving up smoking.
Drink alcohol in moderation: Drinking too much alcohol can also raise your blood pressure. According to the UK Chief Medical Officers, the most anyone – male or female – should drink on a regular basis is 14 units of alcohol a week, spread evenly across the week (xi). Fourteen units of alcohol is the equivalent of six pints of average-strength beer or 10 small glasses of low-strength wine, says the NHS (xii).
Test to check kidney function: If you have a higher-than-normal risk of developing kidney problems, have a chat with your GP about having your kidney function checked at regular intervals, if you’re not already doing so. People with an increased risk include those with high blood pressure or diabetes, people who are obese, those who have kidney problems running in their family, and people who are black or of south Asian origin.
Kidney health may not be a subject many of us know much about, which could explain why some people have problems with their kidneys without realising it. But as this guide shows, there are several simple ways to keep your kidneys healthy. Meanwhile why not take a look around our health library, where you can find lots more information and advice to boost your physical and mental wellbeing.
Available online: https://www.kidneycareuk.org/news-and-campaigns/facts-and-stats/
Available online: https://www.nhs.uk/conditions/kidney-cancer/
Available online: https://www.nhs.uk/live-well/alcohol-support/calculating-alcohol-units/
Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.
Keri Filtness has worked in the Nutrition Industry for 19 years. She is regularly called upon for her professional comments on health and nutrition related news. Her opinions have been featured by BBC3, Prima, Vitality, The Mirror, Woman’s Own and Cycling Weekly, amongst others. She has also worked one to one with journalists, analysing their diets and health concerns and recommending changes and additions, where appropriate.