Skip to Content

What 3 organs are affected by diabetes?

Diabetes is a chronic disease that affects how the body processes blood glucose, or blood sugar. When you have diabetes, your body either can’t make enough insulin or can’t properly use the insulin it makes, causing glucose to build up in the bloodstream. Over time, high blood glucose levels can damage various organs and tissues throughout the body. The three main organs affected by diabetes are the heart, kidneys, and eyes.

What is diabetes?

Diabetes occurs in two main forms:

  • Type 1 diabetes – The body does not produce insulin due to autoimmune destruction of insulin-producing beta cells in the pancreas.
  • Type 2 diabetes – The body becomes resistant to the normal effects of insulin or loses the capacity to produce enough insulin in the pancreas.

Both types of diabetes result in higher than normal blood sugar levels which can damage organs over time. Prediabetes occurs when blood glucose levels are abnormally high but not high enough for a diagnosis of diabetes. Without lifestyle changes to lower blood glucose, prediabetes often leads to type 2 diabetes.

How does diabetes affect the body?

Insulin is required for cells throughout the body to properly take up glucose from the bloodstream and convert it into energy. In diabetes, ineffective insulin results in chronic high blood glucose which can have toxic effects on many organs.


One of the organs most impacted by diabetes is the heart. Both type 1 and type 2 diabetes significantly increase the risk of developing cardiovascular disease.

How does diabetes affect the heart?

There are a few key ways diabetes damages the heart and blood vessels:

  • Atherosclerosis – Diabetes accelerates the buildup of fatty deposits called plaques inside blood vessel walls, leading to atherosclerosis or hardening/narrowing of arteries.
  • Blood vessel damage – Excess glucose cross-links with proteins, damaging blood vessels. This can impair blood flow.
  • Nerve damage (neuropathy) – High blood sugar can damage nerves in the heart, interfering with normal electrical signaling patterns.
  • Abnormal heart rhythms – Damage to blood vessels and nerves increases the risk for abnormal heart rhythms such as atrial fibrillation.
  • Weakened heart muscle – Impaired blood flow and oxygen delivery to the heart may cause areas of heart muscle to die or become damaged.

These issues make the heart less able to pump blood effectively and may lead to heart failure.

Cardiovascular conditions linked to diabetes

Some of the key cardiovascular conditions connected to diabetes include:

  • Coronary artery disease – Narrowing of the heart’s major blood vessels that can cause chest pain or heart attack.
  • Heart failure – When the heart is too weak to efficiently pump blood.
  • Stroke – Impaired blood flow to the brain due to diabetes-related damage to arteries.
  • High blood pressure – Increased risk of hypertension.
  • Peripheral artery disease – Narrowing of leg arteries impairing blood flow to the legs.

Increased risk of death

Cardiovascular disease is the leading cause of death and disability among people with diabetes. Adults with diabetes have heart disease death rates about 2 to 4 times higher than adults without diabetes. Proper management of diabetes and controlling risk factors such as high blood pressure and cholesterol can reduce but not eliminate the increased risk.


The kidneys are also significantly impacted by the effects of diabetes. Over several years, uncontrolled blood glucose damages the blood vessels in the kidneys leading to diabetic nephropathy, a common cause of kidney failure.

How does diabetes affect the kidneys?

There are three main ways elevated blood glucose damages the kidneys:

  • Damage to small blood vessels – Excess glucose constricts and thickens the network of tiny blood vessels (glomeruli) that filter wastes from the blood. This impairs kidney function.
  • Nerve damage (diabetic neuropathy) – High glucose levels can damage nerves in the kidneys, further reducing function.
  • Increased kidney workload – The kidneys attempt to eliminate excess glucose by filtering more blood. This strains the kidneys and accelerates damage.

As kidney function declines, dangerous levels of fluid and waste can build up in the body. Severely reduced kidney function leads to kidney failure.

Diabetic nephropathy stages

Diabetic nephropathy typically develops over several years, getting progressively worse through several stages:

  • Stage 1 – Kidney damage with normal filtration rate.
  • Stage 2 – Some reduction in kidney function. Urine tests show high amounts of a protein called albumin that the kidneys aren’t adequately filtering.
  • Stage 3 – Moderate loss of kidney function (30-59% reduction).
  • Stage 4 – Severe loss of kidney function (60-89% reduction). The body retains dangerous levels of fluid and waste products.
  • Stage 5 – End-stage kidney failure requiring dialysis or kidney transplant (90%+ reduction in function).

Proper diabetes management can slow the progression of kidney damage and delay the onset of end-stage renal disease.

Kidney failure

Diabetes is the leading cause of kidney failure in the United States accounting for around 44% of new cases in 2020. People with diabetes make up over half of the chronic dialysis population. Kidney failure is fatal without a transplant or dialysis treatment. With proper treatment, kidney failure significantly reduces life expectancy.


Diabetes is also a leading cause of blindness among adults due to damage to the small blood vessels in the retina at the back of the eye. This condition is known as diabetic retinopathy.

How does diabetes affect the eyes?

Over time, uncontrolled blood glucose damages the tiny blood vessels that nourish the retina. There are two key problems this causes:

  • Leakage – Weakened blood vessels can leak fluid into the retina, causing it to swell.
  • Blockage – Retinal blood vessels can close off, impairing nourishment to areas of the retina.

As more blood vessels are damaged, areas of the retina become oxygen deprived, releasing chemicals that stimulate abnormal blood vessel growth. These fragile new blood vessels are prone to hemorrhage, scarring, and retinal detachment causing blindness.

Stages of diabetic retinopathy

Like other diabetes complications, diabetic retinopathy typically develops progressively through a series of stages:

  • Mild nonproliferative retinopathy – Small areas of retinal swelling and bleeding.
  • Moderate nonproliferative retinopathy – More widespread areas of retinal bleeding and swelling.
  • Severe nonproliferative retinopathy – Extensive bleeding in the retina with many blocked vessels.
  • Proliferative diabetic retinopathy – Abnormal new retinal blood vessels that are prone to bleeding.

The progression from mild to proliferative retinopathy may take many years. Dilated eye exams are needed to detect changes before vision loss occurs. With proper monitoring and timely treatment, blindness can often be prevented.

Diabetes is a leading cause of blindness

In the United States, diabetes is the most frequent cause of new cases of blindness among adults aged 20–74 years. After 20 years of diabetes, approximately 2% of people become blind and about 10% develop severe visual impairment. Regular eye screening exams and timely treatment can significantly reduce these risks.

Other Complications

While the heart, kidneys and eyes are most severely impacted, chronic high blood glucose also damages nerves and blood vessels throughout the body leading to a number of other complications:

  • Nerve damage (diabetic neuropathy) – Neuropathy can affect nerves in the gastrointestinal tract causing nausea, constipation or diarrhea. It can also damage nerves in the feet leading to numbness, tingling, pain, and increased risk of infection and ulceration.
  • Skin conditions – Poor circulation and neuropathy lead to higher risk of bacterial and fungal skin infections.
  • Hearing impairment – Diabetes may accelerate hearing loss, particularly for high-frequency sounds.
  • Cognitive decline – Diabetes increases the risk of dementia including Alzheimer’s disease.
  • Bone and joint problems – Diabetes may lead to accelerated osteoarthritis and increased risk of bone fractures.

While less common than cardiovascular, kidney and eye conditions, these other issues also significantly impair quality of life.

Preventing Organ Damage

The chronic complications of diabetes can be minimized with prompt diagnosis, optimal management, and lifestyle modification. Important ways to prevent organ damage include:

  • Achieve and maintain healthy blood glucose, blood pressure, and cholesterol levels through a combination of medication and lifestyle changes.
  • Do not smoke – Smoking worsens the artery damage caused by diabetes.
  • Get regular medical check-ups to monitor for diabetes complications.
  • Follow dietary recommendations and maintain a healthy weight.
  • Exercise regularly – At least 150 minutes per week can dramatically improve outcomes.
  • Take all medicines as directed.
  • Learn to check blood glucose levels and manage insulin if needed.
  • Control other diabetes risk factors such as excess body weight.

Early optimization of blood glucose levels provides the best chance of avoiding organ damage and the many complications of poorly managed diabetes over the long-term.

The Main 3 Organs Affected by Diabetes

In summary, diabetes frequently leads to damage of vital organs over an extended period of time. The three organs most impacted are:

  • Heart – Increased risk of coronary artery disease, heart attack, heart failure, stroke, and death.
  • Kidneys – Can progress to kidney failure requiring dialysis or transplant.
  • Eyes – Leading cause of blindness resulting from diabetic retinopathy and retinal damage.

Other common complications include nerve damage, skin conditions, hearing impairment, dementia, and bone/joint disorders.

While diabetes complications develop progressively, timely treatment and lifestyle changes can make a major difference. Controlling blood glucose and cardiovascular risk factors offers the best protection against organ damage and allows people with diabetes to enjoy long and healthy lives.

Frequently Asked Questions

Why do high blood glucose levels damage body organs?

Glucose is normally able to pass from the bloodstream into cells with the assistance of insulin. In diabetes, ineffective insulin results in chronically high blood glucose. These abnormally high levels gradually damage blood vessels and nerves throughout the body. Small blood vessels are especially vulnerable to injury from glucose cross-linking with proteins.

Which organ is affected first by diabetes?

Diabetes impacts different organs at different rates in different people. However, the eyes and kidneys are often the first parts of the body to manifest signs of damage from diabetes. After 5 years with diabetes, the majority of individuals start to develop some background diabetic retinopathy that must be monitored. After 10-15 years, diabetes frequently starts to impact kidney function.

Does diabetes affect the liver?

The liver plays a central role in glucose regulation but is not as frequently permanently damaged by diabetes as other organs. However, non-alcoholic fatty liver disease affects up to 70% of obese individuals with diabetes. This condition can progress to more severe liver damage including cirrhosis.

Can diabetes complications be reversed?

Early in the disease, the impact of diabetes on organs may be partially reversible if blood glucose levels are brought under control. However, over many years, the cumulative damage to organs becomes irreversible. The goal is to manage diabetes optimally from the outset to limit organ damage before it becomes irreparable.

What is the life expectancy of a person with diabetes?

Life expectancy for both type 1 and type 2 diabetes is reduced, mainly due to cardiovascular complications. However, proper management that optimizes glucose levels and cardiovascular risk factors can significantly increase life expectancy toward that of the general population. The importance of early and tight blood glucose control cannot be overemphasized for longevity.

The Impact of Diabetes on Organs – A Summary

Organ Impact of Diabetes Signs of Damage
Heart – Increased risk of coronary artery disease, heart attack, stroke, and heart failure. – Angina, heart attack, arrhythmias, heart failure symptoms (shortness of breath, fatigue).
Kidneys – Can progress to kidney failure requiring dialysis. – Protein in the urine. Decreased kidney filtration rate.
Eyes – Leading cause of blindness due to diabetic retinopathy. – Changes in vision, blind spots, seeing floaters or flashes.
Nerves – Diabetic neuropathy can cause GI problems and foot damage. – Numbness, tingling, pain, particularly in the feet.
Skin – Increased infections and poor wound healing. – Bacterial and fungal skin infections.

Key Takeaways

  • The three main organs damaged by diabetes are the heart, kidneys, and eyes.
  • Cardiovascular disease is the leading cause of death in those with diabetes.
  • Diabetes is the most common cause of kidney failure in the United States.
  • Blindness caused by diabetes often results from diabetic retinopathy.
  • Early optimization of blood glucose with medication, lifestyle changes, and monitoring can prevent or delay organ damage from diabetes.


In diabetes, persistently elevated blood glucose levels damage blood vessels and nerves throughout the body, leading to complications affecting multiple organs over time. The heart, kidneys and eyes in particular are often severely impacted. This results in increased risk of heart attack, stroke, kidney failure, blindness and death.

The good news is that the vascular and organ damage from diabetes is largely preventable and treatable, especially when blood glucose levels are controlled early in the disease course. Regular monitoring and an empowered, proactive approach to diabetes care allows most people with diabetes to prevent debilitating complications and enjoy long, productive lives.