Diabetes can affect far more than blood sugar. Over time, consistently high blood glucose can damage the tiny blood vessels and filtering structures inside the kidneys, gradually reducing how well they work.
This is one of the reasons diabetes is a major risk factor for chronic kidney disease (CKD). The problem can develop slowly, often without noticeable symptoms in the early stages.
If you have diabetes, keeping your blood sugar and blood pressure within the targets set by your healthcare professional is an important part of protecting your kidney function.
Can High Blood Sugar Damage the Kidneys?
Yes. High blood sugar over a long period can damage the blood vessels and tiny filtering units inside the kidneys.
Your kidneys contain millions of microscopic filters called nephrons. Their job is to remove waste and excess fluid from your blood while allowing useful substances to remain in circulation.
When blood glucose remains too high, the blood vessels in these filtering structures can become damaged. Over time, this can interfere with the kidneys’ ability to filter blood properly.
Kidney damage caused by diabetes is commonly referred to as diabetic kidney disease. It can develop gradually over many years.
How Diabetes Affects Kidney Function
The kidneys are constantly filtering blood, so they are exposed to the effects of long-term changes in blood glucose and blood pressure.
When diabetes is poorly controlled, high blood glucose can place stress on the kidney’s filtering system. Continued damage may eventually cause proteins such as albumin to leak into the urine, while kidney filtration can gradually decline.
As kidney function becomes impaired, the body may have more difficulty removing waste and excess fluid.
This is why diabetes management is closely connected to kidney health.
The Connection Between Diabetes and Chronic Kidney Disease
Diabetes is one of the leading causes of chronic kidney disease. Both type 1 and type 2 diabetes can contribute to kidney damage.
The risk is influenced by factors such as how long someone has had diabetes, how well blood glucose is controlled, blood pressure, and other health factors.
If you want to understand more about chronic kidney disease and the different approaches people may consider for supporting kidney health, you can also read our Chronic Kidney Disease Solution review.
That information is separate from medical treatment, and anyone with diabetes or diagnosed kidney disease should continue working with a qualified healthcare professional for personalized care.
Why High Blood Pressure Makes the Problem Worse
Blood sugar is not the only concern for people with diabetes.
High blood pressure can also damage the blood vessels in the kidneys. Because diabetes and high blood pressure frequently occur together, having both conditions can increase the risk of kidney damage.
Managing both blood glucose and blood pressure is therefore an important part of reducing the risk of diabetes-related kidney problems.
Can Diabetes Cause Kidney Disease Without Symptoms?
Yes.
Early diabetic kidney disease often causes few or no noticeable symptoms. Someone can therefore have changes in kidney function without realizing that anything is wrong.
This is why regular kidney testing is particularly important for people with diabetes.
Waiting for symptoms before checking your kidneys can mean missing an opportunity to identify problems earlier.
What Are the Possible Signs of Kidney Problems?
Early kidney disease may not produce obvious symptoms. As kidney function becomes more impaired, however, symptoms can develop.
- Swelling in the feet, ankles, legs, hands, or face
- Changes in urination
- Persistent tiredness
- Nausea or loss of appetite
- Itching
- Muscle cramps
- Difficulty concentrating
- Shortness of breath in more advanced disease
These symptoms can have many different causes and do not automatically mean that diabetes has damaged your kidneys. Testing is needed to determine whether kidney disease is present.
How Is Diabetic Kidney Disease Detected?
Blood and urine tests are commonly used to check kidney health.
Blood Tests
A blood test can measure creatinine, which is used to estimate how effectively your kidneys are filtering blood. This measurement is commonly reported as estimated glomerular filtration rate, or eGFR.
A declining eGFR can indicate reduced kidney function, although your healthcare professional will interpret the result in the context of your overall health.
Urine Tests
Urine testing can look for albumin, a protein that may leak into the urine when the kidney’s filtering system has been damaged.
Albumin in the urine can be an early indication of kidney damage, even before major changes in kidney filtration become apparent.
How Often Should People With Diabetes Have Their Kidneys Checked?
People with diabetes should discuss regular kidney testing with their healthcare professional.
NIDDK recommends kidney disease testing at least yearly for people with type 2 diabetes and for people who have had type 1 diabetes for more than five years.
Your healthcare professional may recommend a different testing schedule depending on your health, kidney function, blood pressure, medications, and other risk factors.
How Can You Protect Your Kidneys If You Have Diabetes?
Protecting kidney function starts with managing the factors that can contribute to kidney damage.
1. Keep Blood Sugar Within Your Target Range
Managing blood glucose is one of the most important things you can do to reduce the risk of diabetes-related complications.
Your healthcare team may recommend regular blood glucose monitoring and A1C testing. Your individual blood sugar target should be determined with your healthcare professional because the appropriate target can vary from person to person.
2. Control Your Blood Pressure
High blood pressure can damage the kidneys independently of diabetes and can further increase the risk of kidney problems when the two conditions occur together.
Monitor your blood pressure as recommended and take prescribed medication according to your healthcare professional’s instructions.
3. Take Your Diabetes Medication as Prescribed
Diabetes medications may be an important part of keeping blood glucose within your target range.
Do not stop, change, or add medication without discussing it with your healthcare professional.
4. Reduce Excess Sodium
Eating too much sodium can make blood pressure more difficult to control.
Processed foods, packaged meals, salty snacks, cured meats, sauces, and many restaurant meals can contain substantial amounts of sodium.
If you have diabetes and kidney disease, your nutritional needs may be more specific, so ask your healthcare professional or a kidney dietitian for individualized advice.
5. Stay Physically Active
Regular physical activity can support blood glucose management, blood pressure control, cardiovascular health, and overall wellbeing.
The right type and amount of exercise depends on your health and fitness level. If you have complications from diabetes or another medical condition, ask your healthcare professional what activities are appropriate.
6. Maintain a Healthy Weight
If you have overweight or obesity, working toward a healthier weight may help improve blood glucose control and reduce cardiovascular risk.
A sustainable approach is generally more useful than extreme diets or rapid weight-loss plans.
7. Don’t Smoke
Smoking damages blood vessels and increases cardiovascular risk. If you smoke, quitting can be an important step toward protecting your overall health and reducing additional strain on your kidneys.
8. Get Enough Sleep
Sleep is another part of overall diabetes management. Poor sleep can make healthy blood glucose and lifestyle management more difficult.
Aim for a consistent sleep routine and discuss persistent sleep problems with your healthcare professional.
What Should You Eat If You Have Diabetes and Want to Protect Your Kidneys?
There is no single diet that is appropriate for every person with diabetes.
A healthy diabetes eating pattern generally emphasizes nutritious foods while limiting excessive added sugar, refined carbohydrates, sodium, and highly processed foods.
However, once chronic kidney disease is present, dietary recommendations can become more complicated.
Depending on kidney function and other medical factors, someone with CKD may need to pay closer attention to sodium, potassium, phosphorus, protein, fluids, or other nutrients.
This means that a food that is generally considered healthy for someone with diabetes may not necessarily be appropriate in unlimited amounts for someone with advanced kidney disease.
If you have both diabetes and CKD, consider working with a registered dietitian or other qualified healthcare professional who understands both conditions.
Does High Blood Sugar Always Cause Kidney Disease?
No. Having diabetes does not mean that kidney disease is inevitable.
However, diabetes significantly increases the risk of developing kidney disease, particularly when blood glucose and blood pressure remain poorly controlled over time.
Regular monitoring and appropriate management can help identify problems early and may help slow or prevent further kidney damage.
What Increases the Risk of Diabetic Kidney Disease?
Several factors can increase the likelihood of kidney problems in people with diabetes.
- Having diabetes for many years
- Persistently high blood glucose
- High blood pressure
- Smoking
- Physical inactivity
- Being overweight or having obesity
- Heart disease
- Eating a diet high in sodium
- A family history of kidney failure
Not every person with these risk factors will develop kidney disease, but addressing modifiable risk factors can be an important part of protecting kidney health.
Common Mistakes People With Diabetes Make About Kidney Health
Waiting for Symptoms
One of the biggest mistakes is assuming that normal energy levels or the absence of pain means the kidneys are healthy.
Early kidney disease can be silent, so testing is important.
Focusing Only on Blood Sugar
Blood glucose is extremely important, but blood pressure also matters. A person with diabetes should pay attention to both factors because uncontrolled blood pressure can independently damage the kidneys.
Following Extreme Diets
Restrictive diets found online may not be appropriate for someone with diabetes or kidney disease.
Your nutritional needs depend on your blood glucose, kidney function, medications, and other health conditions.
Assuming Supplements Can Replace Medical Care
Supplements should not replace diabetes treatment, kidney testing, prescribed medication, or professional medical care.
If you are considering a product marketed for blood sugar or kidney support, discuss it with your healthcare professional first, especially if you take prescription medication.
Frequently Asked Questions
Can high blood sugar damage the kidneys?
Yes. Persistently high blood glucose can damage blood vessels and filtering structures in the kidneys and contribute to chronic kidney disease.
Can diabetes cause kidney failure?
Diabetes can cause chronic kidney disease, and kidney disease can progress over time in some people. However, not everyone with diabetes develops kidney failure. Managing blood glucose, blood pressure, and other risk factors can help protect kidney function.
Can kidney damage from diabetes be reversed?
It depends on the type and extent of the damage. Some early abnormalities may improve when the underlying factors are addressed, while established chronic kidney damage may not be fully reversible. Early detection and appropriate management can help slow further progression.
How do I know if diabetes has affected my kidneys?
You cannot reliably determine this from symptoms alone. Blood and urine tests are used to assess kidney function and look for signs of kidney damage.
What is the most important thing a person with diabetes can do for kidney health?
Work with your healthcare team to manage your blood glucose and blood pressure within your recommended targets, take medications as prescribed, maintain healthy lifestyle habits, and have your kidneys checked regularly.
Final Verdict
Diabetes and kidney health are closely connected. When blood sugar remains high over time, it can damage the tiny blood vessels and filtering structures inside the kidneys. This damage can gradually reduce kidney function and contribute to chronic kidney disease.
The good news is that having diabetes does not mean kidney disease is unavoidable. Managing blood glucose, controlling blood pressure, taking prescribed medications, staying active, eating appropriately, avoiding smoking, and getting regular kidney testing can all play an important role in protecting kidney function.
Most importantly, don’t wait until you develop symptoms before paying attention to your kidneys. Early kidney disease can be difficult to detect without testing.
Medical Disclaimer: This article is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment. If you have diabetes, kidney disease, or concerns about your blood sugar or kidney function, speak with a qualified healthcare professional.
