What is kidney disease, and why do so many people miss it? Kidney problems often develop quietly. Many people live with reduced function for years because the early stages rarely cause clear symptoms. By the time something feels wrong, these organs may already be working below their normal level.
Your kidneys do far more than make urine. They filter your blood, balance fluids and minerals, help control blood pressure and support the production of red blood cells. When they struggle, you can feel it in your energy, your heart and your general wellbeing.
This guide explains what the kidneys do, the warning signs to watch for, common causes, the tests your GP may offer and the everyday habits that help. For official UK information, see the NHS Kidney Disease Information page.
What Is Kidney Disease?
Kidney disease means your kidneys no longer filter blood as well as they should. Doctors usually talk about chronic kidney disease, or CKD, when this reduced function lasts for three months or more.
CKD rarely appears overnight. It tends to creep up over months or years, which is why many people only find out through a routine blood or urine test. Sudden kidney injury is different. It happens quickly, often during a serious illness, and needs urgent medical care.
The good news is that early detection gives you real options. Treatment can slow the condition down, and many people stay well for a long time.
What Is Kidney Function and How Do Your Kidneys Work?
You have two kidneys, each about the size of a fist. They sit on either side of your spine, just below the rib cage.
Each one contains around a million tiny filters called nephrons. Together, they process roughly 180 litres of fluid every day. Most of that fluid returns to your bloodstream. The waste and extra water leave your body as urine.
Nephrons also hold on to what you need, such as glucose and salts. This careful sorting keeps your body’s chemistry steady. Even a small drop in kidney function can affect other organs. If you’d like a closer look at this topic, read our guide to kidney function and its common causes.
Why Kidney Health Matters
These organs act as a control centre for your internal balance, not just a waste-disposal unit. They carry out several jobs at once:
- Help regulate blood pressure through fluid balance and hormones
- Keep sodium, potassium, calcium and phosphate at healthy levels
- Produce erythropoietin, a hormone that supports red blood cell production
- Activate vitamin D, which supports your bones
- Clear waste products such as urea and creatinine from your blood
If they stop doing these jobs, waste and fluid build up. Severe kidney failure is life-threatening without treatment, which is why early detection matters so much.
Early Signs of Kidney Problems
Early kidney disease is often called a “silent” condition. The first signs are mild, and many people put them down to stress, age or a busy week.
Changes in Urination
You might need the toilet more often, especially at night. Some people pass less urine than usual. Foamy urine can suggest protein leaking from the kidneys, and blood can turn urine pink, red or brown.
Tiredness and Weakness
Reduced function can lead to anaemia and a build-up of waste in the blood. Both can leave you tired, low on energy and struggling to concentrate.
Swelling
Extra fluid tends to collect in the feet, ankles, legs and hands. Some people notice puffiness around the eyes in the morning. Doctors call this swelling oedema.
Itchy, Dry Skin
When minerals and waste products fall out of balance, the skin can become dry and itchy. The itching can be persistent and hard to ease with moisturiser alone.
Poor Appetite and Sickness
Waste products in the blood can make you feel sick, put you off food or leave a metallic taste in your mouth.
Signs of More Advanced Kidney Damage
As the condition progresses, symptoms become harder to ignore. Doctors look out for these signs:
- Breathlessness, sometimes from fluid on the lungs or anaemia
- Frequent headaches and dizziness
- Muscle cramps
- Poor sleep
- A metallic taste and bad breath
- Weight changes without trying
- Trouble concentrating
- Blood pressure that becomes harder to control
These symptoms have many possible causes, so they don’t confirm kidney disease on their own. A blood and urine test is the only reliable way to find out. For patient support and practical advice, visit Kidney Care UK.
Common Causes of Kidney Disease
Chronic kidney disease usually builds up slowly. A few well-known conditions and habits account for most cases. Our article on how diabetes and high blood pressure damage the kidneys explains the two biggest causes in more detail.
1. High Blood Pressure
Constant high pressure damages the small blood vessels inside the kidneys. Over time, the filters work less well. The damage can also push blood pressure higher, creating a harmful cycle. High blood pressure strains the heart too, and you can read about heart blockage symptoms and high blood pressure to see the wider picture.
2. Diabetes
Persistently high blood sugar harms the filters. Diabetic kidney disease is one of the most common causes of kidney failure in the UK and worldwide.
3. Long-Term Use of Some Painkillers
Anti-inflammatory painkillers such as ibuprofen can reduce blood flow to the kidneys, particularly if you take them regularly or already have a problem. Ask your pharmacist before using them for long periods.
4. Too Much Salt
A high-salt diet raises blood pressure and makes your body hold on to fluid. Both put extra strain on these organs.
5. Dehydration
Occasional thirst won’t harm healthy kidneys. Repeated or severe dehydration can cause sudden injury, especially during illness with vomiting or diarrhoea.
6. Lifestyle and Other Risk Factors
Smoking, heavy drinking, being overweight and getting little exercise all raise your risk. So do repeated infections, blocked urine flow and a family history of kidney disease.
Kidney Stones and Infections
Not every kidney problem is chronic. Stones and infections are common and often painful, though most people recover with prompt treatment.
A stone can cause sharp pain in the side or back, nausea and blood in the urine. An infection may bring fever, shivering and pain in the loins, often after bladder symptoms. Both need medical attention, so don’t wait it out at home.
What Is Kidney Failure? Understanding the Stages
Kidney failure means the kidneys have lost most of their ability to filter blood. Doctors describe chronic disease in five stages, based on your eGFR result and the amount of protein in your urine. Stage 1 is the mildest, and stage 5 is kidney failure.
Many people in stages 1 to 3 feel well and never need more than monitoring and sensible treatment. Your GP or kidney specialist will explain which stage applies to you and what it means for your care.
When Should You Have a Kidney Test?
Your GP may suggest tests if you have symptoms. They may also offer regular checks if you have a higher risk.
That includes people with diabetes, high blood pressure, heart disease or a family history of kidney failure. If you’re in one of these groups, a yearly check is common. Ask your GP what suits your situation.
Main Kidney Tests Explained
Blood Test: Creatinine and eGFR
This test measures creatinine, a waste product, in your blood. Your lab uses the result to estimate your eGFR, which shows how well your kidneys filter. A lower eGFR points to reduced function.
Urine Test: Protein and ACR
A urine sample can show protein or blood. The albumin creatinine ratio (ACR) picks up small amounts of protein leakage, which is often an early sign of damage.
Ultrasound Scan
An ultrasound shows the size and shape of the organs. It can reveal cysts, stones or a blockage.
Blood Pressure Checks
Regular readings matter because high blood pressure both causes and worsens damage. Many pharmacies and surgeries offer free checks.
For wider patient education, the National Kidney Foundation offers helpful guides.
How Kidney Disease Is Managed
Chronic kidney disease can’t usually be cured, but treatment can slow it down. Many people live for years with stable function when they follow their care plan.
Lifestyle Changes
Eating well, staying active, stopping smoking and keeping to a healthy weight all lower the workload.
Regular Monitoring
Repeat blood and urine tests show whether your results are steady or changing. Your care team uses them to adjust your plan.
Medication
Your doctor may prescribe medicines to control blood pressure, blood sugar or cholesterol. Take them as directed, and don’t stop without speaking to your GP.
Advanced Treatment
If function falls very low, treatment options include dialysis or a transplant. A specialist team will talk you through the choices.
Eating for Kidney Health
For most people, a kidney-friendly diet looks like a healthy diet for the heart: plenty of vegetables, fruit and whole grains, with less salt. If you already have kidney disease, your needs may differ. You may need to limit potassium or phosphate, for example. Ask your GP or a registered dietitian before changing what you eat.
Cholesterol matters here too, because the same habits protect your heart and kidneys. Our guide on how high cholesterol affects your health covers it in more detail.
Foods That Generally Help
- Fruit such as apples and berries
- Vegetables such as cabbage and cauliflower
- Whole grains such as oats and brown rice
- Fish, chicken and other lean protein in sensible portions
- Olive oil in place of butter or lard
Foods to Limit
- Processed and packaged foods, which are often high in salt
- Salty meals, takeaways and added table salt
- Sugary soft drinks
- Deep-fried and fast food
Drinking Enough Water
Water helps your body clear waste and supports healthy urine flow. Staying well hydrated also lowers your chance of stones and urinary tract infections.
A good guide is to drink enough that your urine stays pale yellow. If you have advanced kidney disease or heart failure, your doctor may set a fluid limit, so follow their advice instead of a general target.
Everyday Habits That Protect Your Kidneys
- Drink regularly through the day, and more in hot weather or when you’re unwell
- Eat a balanced diet and keep salt low
- Aim for at least 150 minutes of moderate activity a week, as the NHS recommends
- Check your blood pressure regularly
- Take painkillers only when you need them, and ask your pharmacist first if you use them often
- Don’t smoke, and keep alcohol within recommended limits
- Attend the health checks your GP offers
When to See a GP
Book a GP appointment if you notice any of these:
- Blood in your urine, or urine that stays foamy
- Swelling in your ankles, legs, hands or face that doesn’t settle
- Tiredness, itching or sickness that lasts more than a couple of weeks
- A big change in how often you pass urine
- Diabetes, high blood pressure or a family history of kidney disease with no recent check
Get urgent help immediately if you have severe breathlessness, chest pain, confusion, or very little urine alongside serious illness. Call 999 in the UK or 911 in the USA.
Can You Prevent Kidney Problems?
You can’t prevent every case, but you can lower your risk a great deal. Keeping blood pressure and blood sugar under control is the biggest step. Healthy eating, regular activity and limited salt all help too.
Catching a problem early also gives treatment the best chance to slow it down. That’s why regular checks matter if you’re in a higher-risk group.
Frequently Asked Questions About Kidney Health
What is kidney disease in simple words?
Kidney disease means your kidneys can’t clean your blood as well as they should. Waste and extra fluid then build up in the body. It usually develops slowly and causes few symptoms early on, so blood and urine tests are the main way doctors find it.
Can a person live with one kidney?
Yes. Many people live healthy lives with one kidney, including those born with one or who donated one. A single healthy kidney usually does enough work for the body. Doctors still advise regular blood pressure and kidney checks, and protecting it from injury and infection.
Does kidney disease always cause symptoms?
No. Early kidney disease often causes no symptoms at all. Many people find out only after a routine blood or urine test. This is why people with diabetes or high blood pressure are offered regular checks, even when they feel completely well.
Is kidney damage permanent?
It depends on the cause. Sudden injury can sometimes recover with prompt treatment. Long-term damage from chronic disease usually can’t be reversed. Treatment can still slow it down, so seeing your GP early gives you the best chance of protecting the function you have.
How often should you have kidney tests?
Healthy adults without risk factors don’t usually need routine tests. If you have diabetes, high blood pressure or existing kidney disease, tests are often done at least once a year. Your GP may check more often depending on your results.
Final Thoughts: What Is Kidney Disease and What Can You Do?
So, what is kidney disease? It’s a slow, often silent loss of the filtering work your kidneys do around the clock. That makes awareness your best tool.
Know the early signs, ask about testing if you’re at higher risk, and keep up the basics: balanced meals, less salt, regular activity and well-controlled blood pressure. These steps won’t guarantee perfect kidney health, but they give you the best support.
If something feels wrong, or you’re worried about your risk, speak to your GP. Early advice can make a real difference.
Sources and further reading
Disclaimer: This article is for general information only and doesn’t replace advice from a doctor or other qualified healthcare professional. Speak to your GP or pharmacist about your own symptoms, tests, medicines or diet, and seek urgent help if you feel seriously unwell.
