How Are Your Body Organs Affected by Diabetes?

Diabetes is a common condition that affects 34 million Americans. It is a disease that can be managed with a treatment plan, but if someone who has diabetes does not take medications or actions to control their high blood sugar level (hyperglycemia), it can lead to a plethora of health issues.

Organs specifically, such as the heart, brain, and kidneys, are negatively affected by chronically-elevated blood glucose, which can lead to other comorbidities (additional conditions). For people with type 1 and type 2 diabetes, finding a treatment plan that works is vital to avoiding these problems.

Woman checking diabetes monitor while having breakfast on table at home

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The heart is part of the circulatory system, also known as the cardiovascular system. The circulatory system also includes blood vessels, which help transport oxygen and nutrients to organs and tissues, as well as harmful carbon dioxide and other toxins or waste in the body.

The four main parts of the circulatory system include the heart, arteries, veins, and capillaries. Each part has a specific job:

  • Capillaries: Facilitate oxygen, nutrients, and waste exchange between other parts of the body
  • Veins: Carry blood that has had the oxygen removed back to the heart
  • Arteries: When oxygen is replenished in the blood by the heart, arteries transport the oxygenated blood away from the heart and throughout the circulatory system
  • Heart: Utilizes blood vessels to pump blood throughout the entire body

The American Heart Association considers diabetes to be one of the seven major controllable risk factors for cardiovascular disease (CVD), which includes all types of heart disease, stroke, and blood vessel disease.

The most common type of CVD, coronary artery disease, is caused by the buildup of plaque (cholesterol deposit) in the walls of the arteries.

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

Diabetes can cause damage over time to the blood vessels and nerves that control the heart. Therefore, the longer someone has diabetes, the higher the chances that they will develop heart disease.

Also, people with diabetes often have other conditions that increase the risk of heart disease, such as high blood pressure, high cholesterol, and high triglycerides.


The kidneys are bean-shaped organs roughly the size of a fist that sit below the rib cage beside the spine. They are part of the renal system, which also includes the ureters, bladder, and urethra.

The kidneys work as a filtration system and remove waste, extra fluid, and acid from the body. This filtration is designed to keep a healthy balance of water, salts, and minerals in the blood. The kidneys can also create vital hormones, such as vitamin D and erythropoietin.

Over time, high levels of sugar in the blood caused by diabetes can damage blood vessels in the kidneys and impair their ability to clean the body. This can lead 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 develop kidney failure. For those with type 2 diabetes, 10% to 40% of people are affected.


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

Studies have shown that people with diabetes have lower levels of both grey matter density and volume in various parts of the brain. Gray matter is a major part of the central nervous system and plays a role in daily human functioning. If there is less density or volume in grey matter, it can affect a variety of neurological functions.

Diabetes can also damage small blood vessels in the brain, which can lead to strokes or the death of brain tissue. It can also cause an issue between certain pathways of communication in the brain.


Uncontrolled diabetes has been shown to reduce lung function. This reduction can lead to more mild complications such as asthma or more severe complications like pulmonary fibrosis. The mechanism behind lung dysfunction in people with diabetes isn’t as clearly understood as it is with other organs, even though the connection has been made. Some theories suggest that it may be caused by inflammation.

Research has suggested that hypoglycemic drugs may play a role in the development of lung diseases in people with diabetes. One study found that different medications may affect the lungs. For example, a common diabetes drug metformin is thought to be therapeutic against lung disease, whereas insulin can make lung disease worse.


Diabetes and the pancreas are closely linked because the pancreas produces insulin, and when it doesn’t produce enough or any insulin at all, it leads to high blood sugar.

The cause of type 1 diabetes is this lack of insulin production. Type 2 diabetes, on the other hand, occurs when the body builds up a resistance to insulin. This puts strain on the pancreas as it tries to produce more than it typically needs to.

Type 2 diabetes is linked to an increased risk of developing pancreatic cancer. Both pancreatic cancer and diabetes can be a cause or a consequence of either disease. Diabetes can increase the risk of developing pancreatic cancer and having pancreatic cancer can sometimes lead to the development of diabetes. 

Mouth and Teeth

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

Gum disease can be more severe and take longer to heal in people with diabetes. In turn, having gum disease can make your blood glucose hard to control.

Plaque that is not removed hardens over time into tartar and collects above the gum line. Tartar makes it more difficult to brush and clean between teeth. The gums become red and swollen, and bleed easily, which are signs of unhealthy or inflamed gums called gingivitis.

When gingivitis is not treated, it can advance to a gum disease called periodontitis. In this condition, the gums pull away from the teeth and form spaces called pockets, which slowly become infected. This infection can last a long time.

If periodontitis is not treated, the gums, bones, and tissue that support the teeth are destroyed. Teeth may become loose and might need to be removed.

Stomach and Small Intestines

High blood sugar levels can damage the vagus nerve, which runs from the brainstem down to the abdomen. This damage inhibits the proper functioning of the stomach, rendering it unable to empty food as it should. This condition is known as gastroparesis.

The food a person eats will pass through the stomach slower than it’s supposed to, which leads to complications such as:

  • Dehydration
  • Stomach acid leaking out of the stomach and into the food pipe—a condition known as gastrooesophageal 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.


Eye symptoms like blurry vision are commonly some of the earliest symptoms of diabetes. Over time, diabetes can lead to diabetic retinopathy, which can lead to vision problems and blindness.

It is caused by damage to blood vessels in the retina, a layer of tissue in the back of the eye that is sensitive to light. High levels of sugar in the blood can damage the retina and blood vessels surrounding it.

This damage leads to the growth of new but weak blood vessels to make up for the ones that are no longer working.

Diabetic retinopathy can also lead to other complications involving the eyes, such as:

  • Diabetic macular edema: The new and weak blood vessels in the eye begin to leak fluid and blood into the retina, causing swelling to the macula, the center of the retina.
  • Neovascular glaucoma: This secondary type of glaucoma occurs when new blood vessels close over the angle of the eye, where the cornea meets the iris.

Treatment for vision issues caused by diabetes should be prompt. Since the condition is typically irreversible, treatment will help keep it from getting worse or progressing toward total blindness.


When a person with diabetes has a constantly high level of sugar in their blood, it can lead to poor circulation. This, in turn, damages skin health and impairs wound healing.

Although skin ailments can occur to anyone, there are specific conditions that only happen to those with diabetes, including:

  • Diabetic dermopathy: This condition presents with small, brown, and round lesions on the shins. Roughly 55% of people with diabetes will develop diabetic dermopathy.
  • Necrobiosis lipoidica diabeticorum: Less than 1% of people with diabetes will develop necrobiosis lipoidica diabeticorum. It presents with red bumps on the lower legs of the body in the early stages and advances to flattened, shiny, yellow, and brown raised lesions.
  • Diabetic blisters: Diabetic blisters look the same as blisters that form after a burn, but are not painful. They tend to develop in clusters.
  • Eruptive xanthomatosis: This skin condition appears as small yellow and red bumps.

Another skin condition that is common in people with diabetes is foot ulcers. Typically found on the big toes and balls of the feet, diabetic foot ulcers can be mild or severe. The Wagner Ulcer Classification System is often used to determine the severity of these ulcers on a scale of 0 to 5, with 0 being a possible healed lesion and 5 being a severe case of gangrene (tissue death) caused by the ulcer.

Sexual Organs

When it comes to the male sex organ, damage to the vascular system leads to a decrease in blood flow. Damage to the communication between nerves can also pose an issue because it impairs the body's ability to send blood to the penis. These two problems can cause erectile dysfunction in men with diabetes.

For women, nerve damage caused by diabetes can lead to vaginal dryness. Women can also suffer from a lack of blood flow to their reproductive organs due to blood vessel damage, which makes it difficult for blood to reach these organs. 

Both men and women with diabetes can experience fertility issues. Diabetes can lead to low testosterone levels, which can affect sperm count and lead to a decrease in sex drive. The health of sperm relies heavily on glucose metabolism, and since it's compromised in people with diabetes, it is negatively affected. Mature sperms have a difficult time fertilizing an egg, and their motility also suffers.

In people without diabetes, insulin binds to specific receptors in the ovaries to help drive the production of hormones meant to maintain reproductive tissues and regulate ovulation. For people with diabetes who don't have enough insulin or have insulin resistance, this process is hindered.

Diabetes has also been linked to polycystic ovary syndrome (PCOS), a condition caused by high levels of testosterone in women. It can lead to an impaired ability to ovulate, which makes it difficult for people to get pregnant.

A Word From Verywell

Having diabetes can be difficult, especially if it is not under control. This condition can affect many different organ systems and cause comorbid diseases that negatively affect your health. Following your treatment plan to manage diabetes can decrease the risk of developing additional health problems. There are many treatment options available for those who have either type 1 or type 2 diabetes, and adhering to your plan is vital to your overall health.  

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