How Are Your Body Organs Affected by Diabetes?

Diabetes can affect many major organs, including your heart, eyes, kidneys, and brain. When the disease isn't well-controlled, it can lead to many serious comorbidities, which are conditions that occur alongside diabetes. For people with type 1 and type 2 diabetes, finding a treatment plan that works is vital to avoid these problems.

This article looks at some of the health problems that high blood sugar can cause in your body's organs.

Woman checking diabetes monitor while having breakfast on table at home

Maskot / Getty Images

Heart

The heart is part of the cardiovascular or circulatory system. This body system also includes your blood vessels, which transport oxygen and nutrients to your organs and tissues. Your blood vessels also help remove carbon dioxide, toxins, and waste.

There are four main parts of the circulatory system. Each part has a specific job:

  • Capillaries: These are your body's smallest blood vessels. They carry oxygen and nutrients to distant parts of the body and deliver waste products to the kidneys and liver. They also transport carbon dioxide to the lungs so it can be exhaled.
  • Veins: Your veins carry blood that has had the oxygen removed back to the heart.
  • Arteries: Arteries transport oxygen-rich blood from the heart throughout the circulatory system.
  • Heart: The heart is the muscle that pumps blood throughout the entire body.

The American Heart Association lists diabetes as one of the seven major controllable risk factors for cardiovascular disease (CVD). CVDs include all types of heart disease, stroke, and blood vessel disease.

The most common type of CVD is coronary artery disease (CAD). It is caused by the buildup of plaque (cholesterol) in the walls of the arteries. Diabetes can put you at higher risk for CAD because it can cause problems with your platelets, the cells that help your blood clot. When you have diabetes, you may also form plaques that are more prone to breaking off and blocking blood flow.

People with diabetes are two to four times more likely to develop cardiovascular disease than people without diabetes. 

Over time, diabetes can also cause damage to the blood vessels and nerves that control the heart. The longer you have diabetes, the higher the chances you will develop heart disease.

People with diabetes often have other conditions that increase the risk of heart disease, including:

Kidneys

The kidneys are bean-shaped organs located below the rib cage and beside the spine. Each is roughly the size of a fist. They are part of the renal system, which also includes:

  • Ureters are the tubes that take urine from your kidneys to your bladder
  • The bladder stores urine until it can be expelled
  • The urethra removes urine from the body

The kidneys work as a filtration system. They remove waste, extra fluid, and acid from the body. Healthy kidneys help keep a good balance of water, salts, and minerals in the blood.

The kidneys also produce vitamin D and erythropoietin. Vitamin D helps your body absorb calcium and promotes a healthy immune system. Erythropoietin is a hormone that stimulates the production of red blood cells.

Over time, high blood sugar caused by diabetes can damage blood vessels in your kidneys. This can impair their ability to clean the body, leading to a buildup of waste and fluid in the blood. This type of kidney disease is known as diabetic nephropathy.

If left untreated, diabetic nephropathy can cause kidney failure, which can be life-threatening.

Roughly 30% of people with type 1 diabetes and 10% to 40% of people with type 2 diabetes develop kidney failure.

Brain

High blood sugar can affect cognition, specifically thinking and memory. Research has also shown that diabetes can change the structure of your brain. Because of this, people with diabetes are at increased risk of cognitive decline and are 50% more likely to develop dementia than those without diabetes.

Studies have shown that people with diabetes have lower levels of gray matter density and volume in various parts of the brain. Gray matter is a major part of the central nervous system. It plays a role in daily functioning. Reduced gray matter density or volume can affect a variety of brain and nerve functions.

Diabetes can also damage small blood vessels in the brain. This can lead to strokes or the death of brain tissue.

Lungs

Uncontrolled diabetes may reduce lung function. This can lead to mild complications like asthma or more severe complications like pulmonary fibrosis.

Researchers don't know why people with diabetes can have lung problems. Some think inflammation may be the root cause.

Some studies suggest that drugs that treat low blood sugar may contribute to lung disease in people with diabetes. One found that different medications may affect the lungs in different ways. For example, the common diabetes drug Glucophage (metformin) is thought to work against lung disease, while insulin may make lung disease worse.

Pancreas

Diabetes and the pancreas are closely linked. This is because your pancreas produces insulin. High blood sugar can happen when your pancreas doesn’t produce enough or any insulin.

Type 1 diabetes is caused by this lack of insulin production. Type 2 diabetes, on the other hand, happens when your body builds up insulin resistance. This puts strain on the pancreas as it tries to produce more insulin than it normally needs to.

Pancreatic cancer can be a consequence of diabetes, but it can also be the cause. People with type 2 diabetes are at increased risk of developing pancreatic cancer, and pancreatic cancer can also lead to the development of diabetes. 

Mouth and Teeth

Glucose is present in your saliva. When your diabetes is not controlled, high glucose levels in your saliva help harmful bacteria grow. These can combine with food to form a soft, sticky film called plaque. Some types of plaque cause tooth decay or cavities. Others cause gum disease and bad breath.

When you have diabetes, gum disease can be more severe and take longer to heal. Having gum disease can also make your blood glucose hard to control.

Plaque can harden over time into tartar, making it more difficult to brush and clean between teeth. When this happens, the gums may become red and swollen, and bleed easily. These are signs of a gum disease called gingivitis.

Untreated gingivitis can advance to a gum disease called periodontitis. When you have this condition, the gums pull away from the teeth and form pockets. These pockets become infected, and the infection can last a long time.

Untreated periodontitis can destroy the gums, bones, and tissue that support the teeth. Your teeth may become loose and might need to be removed.

Stomach and Small Intestines

High blood sugar levels can damage the vagus nerve. This is the nerve that runs from the brainstem down to the abdomen. When the vagus nerve is damaged, it can cause a condition known as gastroparesis.

When you have this condition, your stomach empties food much slower than it's supposed to. This can lead to complications like:

  • Dehydration
  • Stomach acid that leaks into the food pipe, a condition known as gastroesophageal reflux disease (GERD)
  • Malnutrition from the body not digesting food properly
  • Unpredictable changes in blood sugar levels

Roughly 20% to 50% of people with diabetes will experience gastroparesis.

Eyes

Sometimes, eye symptoms like blurry vision are the first symptoms of diabetes. Over time, diabetes can lead to diabetic retinopathy. This condition can cause vision problems and blindness.

High blood sugar can damage the retina and surrounding blood vessels. The retina is a layer of tissue in the back of the eye that is sensitive to light. When this happens, your body tries to compensate by producing new, abnormal blood vessels that are much weaker and prone to bleeding.

Diabetic retinopathy can cause other eye problems, such as:

  • Diabetic macular edema: The new, weaker blood vessels leak fluid and blood into the retina. This causes swelling of the macula, the center of the retina.
  • Neovascular glaucoma: This secondary type of glaucoma occurs when new blood vessels close over the part of the eye where the cornea meets the iris. The cornea is the clear tissue at the front of your eye. The iris is the colored part of your eye.

If you have diabetes and are experiencing vision problems, seek medical care right away. These vision problems may be irreversible, and treatment can stop them from progressing to total blindness.

Skin

High blood sugar can cause poor circulation. This can damage your skin and make it hard for your body to repair wounds.

Anyone can get a skin condition, but certain conditions only happen to people with diabetes. These include:

  • Diabetic dermopathy: This causes small, round, brown lesions on the shins. Roughly 55% of people with diabetes will develop this condition.
  • Necrobiosis lipoidica diabeticorum: In the early stages, this condition causes red bumps to form on the lower legs. In later stages, the lesions become flat-topped and shiny and may be yellow or brown. Less than 1% of people with diabetes will develop this condition.
  • Diabetic blisters: Diabetic blisters look like blisters that form after a burn, but they are not painful. They tend to develop in clusters.
  • Eruptive xanthomatosis: This skin condition appears as small yellow and red bumps.

Foot ulcers are also common in people with diabetes. They are typically found on the big toes and balls of the feet and can be mild or severe. Their severity is usually measured on a scale of 0 to 5. A possible healed lesion is a 0, while 5 is a severe case of gangrene (tissue death).

Sexual Organs

Circulatory system damage causes a decrease in blood flow. This, along with damage to nerves and their ability to send signals, can impair blood flow to the penis. This can cause erectile dysfunction in males with diabetes.

Sperm health also relies on your body's ability to process glucose. When you have diabetes, this ability is compromised, which can lead to poor sperm health. Mature sperm may not be able to fertilize an egg, and they may also be less mobile.

Both males and females with diabetes can experience fertility issues. In males, diabetes can lead to low testosterone levels. This can affect sperm count and lead to a decrease in sex drive.

Among females, diabetes can also cause nerve damage that can lead to vaginal dryness. Blood vessel damage can also result in a lack of blood flow to female reproductive organs. 

In females without diabetes, insulin helps drive the production of the hormones that maintain reproductive tissues and regulate ovulation. When you have diabetes, this process doesn't work as well.

Diabetes has also been linked to polycystic ovary syndrome (PCOS). This condition is caused by high testosterone levels. It can impair ovulation or the release of an egg. This makes it difficult to get pregnant.

Summary

When you have uncontrolled diabetes, you are at increased risk for several health problems. These problems can affect major organs and organ systems, such as your heart and blood vessels, kidneys, lungs, pancreas, digestive system, and brain. Uncontrolled blood sugar can also affect your mouth and teeth, eyes, skin, and sexual organs. 

Importantly, diabetes can put you at risk for life-threatening conditions like heart disease, pancreatic cancer, and kidney failure. Keeping your blood sugar under control is the best way to avoid these serious health problems.

A Word From Verywell

Having diabetes can be difficult, especially if it's not controlled. Diabetes can affect many different organ systems and cause other diseases that negatively affect your health.

If you have diabetes, it is important to follow your treatment plan. Controlling your diabetes can decrease the risk of developing additional health problems. There are many treatment options available for both type 1 and type 2 diabetes. Working with your healthcare provider to find the right treatment plan and then sticking to it is vital for your overall health.  

29 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Library of Medicine. How does the blood circulatory system work?

  2. Matheus AS, Tannus LR, Cobas RA, Palma CC, Negrato CA, Gomes MB. Impact of diabetes on cardiovascular disease: an update. Int J Hypertens. 2013;2013:653789. doi:10.1155/2013/653789

  3. Centers for Disease Control and Prevention. Diabetes and your heart.

  4. Al-Nozha MM, Ismail HM, Al-Nozha OM. Coronary artery disease and diabetes mellitus. J Taibah Univ Med Sci. 2016;11(4):330-338. doi:10.1016/j.jtumed.2016.03.005

  5. Johns Hopkins Medicine. Diabetes and heart disease.

  6. Centers for Disease Control and Prevention. Diabetes and your heart.

  7. Sahay M, Kalra S, Bandgar T. Renal endocrinology: the new frontier. Indian J Endocrinol Metab. 2012;16(2):154-155. doi:10.4103/2230-8210.93729

  8. Sulaiman MK. Diabetic nephropathy: Recent advances in pathophysiology and challenges in dietary management. Diabetol Metab Syndr. 2019;11:7. doi:10.1186/s13098-019-0403-4

  9. National Kidney Foundation. Diabetes - a major risk factor for kidney disease.

  10. Moheet A, Mangia S, Seaquist ER. Impact of diabetes on cognitive function and brain structure. Ann N Y Acad Sci. 2015;1353:60-71. doi:10.1111/nyas.12807

  11. Chen R, Ovbiagele B, Feng W. Diabetes and stroke: epidemiology, pathophysiology, pharmaceuticals and outcomes. Am J Med Sci. 2016;351(4):380-386. doi:10.1016/j.amjms.2016.01.011

  12. Kolahian S, Leiss V, Nürnberg B. Diabetic lung disease: fact or fiction? Rev Endocr Metab Disord. 2019;20(3):303-319. doi:10.1007/s11154-019-09516-w

  13. Yeh F, Dixon AE, Marion S, et al. Obesity in adults is associated with reduced lung function in metabolic syndrome and diabetes: The Strong Heart Study. Diabetes Care. 2011;34(10):2306-2313. doi:10.2337/dc11-0682

  14. Khateeb J, Fuchs E, Khamaisi M. Diabetes and lung disease: a neglected relationship. Rev Diabet Stud. 2019;15:1-15. doi:10.1900/RDS.2019.15.1

  15. Houshang A, Alizadeh M. Diabetes mellitus and pancreas: an overview. JOP J Pancreas; 2020;21(4):72-73.

  16. National Institute of Diabetes and Digestive and Kidney Diseases. Diabetes, gum disease, and other related conditions.

  17. National Institute of Diabetes and Digestive and Kidney Diseases. Gastroparesis

  18. Centers for Disease Control and Prevention. Diabetes and digestion.

  19. National Health Service. Gastroparesis.

  20. Krishnasamy S, Abell TL. Diabetic gastroparesis: principles and current trends in management. Diabetes Ther. 2018;9(Suppl 1):1-42. doi:10.1007/s13300-018-0454-9

  21. National Eye Institute. Diabetic retinopathy.

  22. American Diabetes Association. Skin complications.

  23. George S, Walton S. Diabetic dermopathy. Br J Diabetes Vasc Dis. 2014;14:95-97. doi:10.15277/bjdvd.2014.027

  24. Duff M, Demidova O, Blackburn S, Shubrook J. Cutaneous manifestations of diabetes mellitus. Clin Diabetes. 2015;33(1):40-8. doi:10.2337/diaclin.33.1.40

  25. Huang ET, Mansouri J, Murad MH, et al. A clinical practice guideline for the use of hyperbaric oxygen therapy in the treatment of diabetic foot ulcers. Undersea Hyperb Med. 2015;42(3):205-245.

  26. American Diabetes Association. Sex and diabetes.

  27. Ding GL, Liu Y, Liu ME, et al. The effects of diabetes on male fertility and epigenetic regulation during spermatogenesis. Asian J Androl. 2015;17(6):948-953. doi:10.4103/1008-682X.150844

  28. Nandi A, Poretsky L. Diabetes and the female reproductive system. Endocrinol Metab Clin North Am. 2013;42(4):915-946. doi:10.1016/j.ecl.2013.07.007

  29. Centers for Disease Control and Prevention. PCOS (polycystic ovary syndrome) and diabetes.

By Angelica Bottaro
Angelica Bottaro is a professional freelance writer with over 5 years of experience. She has been educated in both psychology and journalism, and her dual education has given her the research and writing skills needed to deliver sound and engaging content in the health space.