The term “diabetes mellitus” encompasses various metabolic disorders. They all manifest as chronically elevated blood sugar levels (hyperglycemia). These conditions are caused either by insulin resistance or insulin deficiency. In some cases, both causes occur simultaneously.
The most common forms of the disease are type 1 and type 2 diabetes. In addition, the following types of diabetes are known, among others:
- Pancreatic disorders (pancreatitis, hemochromatosis, cystic fibrosis),
- genetic defects in insulin action,
- drug- or chemical-induced diabetes (caused by neuroleptics, glucocorticoids, pentamidine, alpha-interferon),
- rare forms of autoimmune diabetes,
- diabetes caused by infections, and
- gestational diabetes.
The symptoms associated with diabetes mellitus depend on how advanced the disease is. In the early stages, both type 1 and type 2 diabetes may present with no symptoms or only mild ones.
Typical symptoms include:
- excessive thirst,
- frequent urination,
- fatigue and exhaustion,
- intense hunger,
- itching,
- vision problems, and
- susceptibility to infections.
Type 2 diabetes mellitus, in particular, often progresses without any symptoms at all in the early stages. It is therefore frequently detected only by chance during routine checkups. Many people with the condition have such mild symptoms that they do not even seek medical attention. As a result, this form of the disease is often not recognized until it has already caused long-term damage.
With type 1 diabetes mellitus, noticeable symptoms often do not appear until months later. During this time, the insulin-producing islet cells in the pancreas are destroyed. Only when this process is about 80 percent complete is the body no longer able to compensate for the insulin deficiency. Only then do symptoms appear. However, these symptoms are usually much more pronounced than in type 2 diabetes.
Occasionally, a diabetic coma triggered by very high blood sugar levels can be the first sign of type 1 diabetes. Symptoms of this include loss of consciousness and a characteristic acetone odor on the breath.
Type 1 diabetes mellitus is caused by a lack of insulin. This results from the destruction of the cells in the pancreas responsible for insulin production. Most new cases occur in children between the ages of 11 and 13.
Type 2 diabetes mellitus is caused by the body’s reduced response to insulin. This is due to impaired function of the beta cells. Neither of these factors alone would cause diabetes. Together, however, they lead to a disruption of glucose homeostasis (blood sugar regulation).
Type 2 diabetes usually does not become apparent until after the age of 40. In addition to a genetic predisposition, triggering factors include
In most patients, the combination of these risk factors leads to the onset of the disease. The video illustrates how insulin works in a healthy body:
If diabetes mellitus is suspected, the doctor makes the diagnosis based on blood glucose levels. Fasting blood sugar levels are typically less than 90 milligrams per deciliter in whole blood or less than 100 milligrams per deciliter in blood plasma. After eating, levels rise to a maximum of 140 milligrams per deciliter.
The following indicate the presence of diabetes:
- a random blood sugar level of more than 200 milligrams per deciliter along with classic symptoms of diabetes, or
- a fasting blood glucose level of more than 110 milligrams per deciliter in whole blood or 126 milligrams per deciliter in blood plasma, or
- an oGTT 2-hour value of more than 200 milligrams per deciliter (oGTT = oral glucose tolerance test) or
- an HbA1c level higher than 6.5 percent.
The concentration of sugar in the urine can also indicate diabetes. If the blood glucose level exceeds 180 milligrams per deciliter, the renal threshold for glucose is exceeded. The body then excretes the excess sugar in the urine. The excreted glucose can be detected in the urine using test strips.
During pregnancy, the renal threshold is slightly lower, so even healthy women may excrete small amounts of sugar. To rule out gestational diabetes, the doctor therefore performs additional tests. If the body’s cells lose the ability to utilize sugar due to a lack of insulin, they meet their energy needs with the help of so-called ketone bodies. These are fat metabolism byproducts produced by the liver.
An excess of ketone bodies is a sign that diabetes is getting out of control and the body is becoming overly acidic (ketoacidosis). To detect ketone bodies in the urine, the doctor also uses a test strip. If initial tests yield inconclusive blood sugar levels, the oral glucose tolerance test (oGTT) is performed. In this test, the doctor draws blood from the patient to determine the blood sugar level.
The patient must eat a diet rich in carbohydrates for the three days prior to the test and fast for at least ten hours before the blood draw. This means no food, no alcohol, and no smoking. On the day of the test, after the first blood draw, the patient drinks 75 grams of glucose dissolved in 250 to 300 ml of water within five minutes. Another blood sample is taken two hours later.
People with diabetes must regularly monitor their blood sugar levels © Kwangmoo / Fotolia
In this test, blood sugar levels in non-diabetics
- less than 100 milligrams per deciliter when fasting and
- less than 140 milligrams per deciliter after two hours.
In contrast, fasting levels of
- over 100 to 125 milligrams per deciliter indicate abnormal fasting glucose, and
- a two-hour level of more than 140 to 199 milligrams per deciliter
indicates impaired glucose tolerance. Diabetes mellitus is diagnosed when the fasting blood glucose level in serum
- is at least 100 milligrams per deciliter or, in blood plasma, at least 126 milligrams per deciliter, and
- the value measured after two hours is greater than 200 milligrams per deciliter
.
The right diet for type 1 and type 2 diabetes can completely cure diabetes mellitus
A sensible dietary regimen plays a crucial role in managing diabetes. A diabetes-friendly diet essentially corresponds to the balanced diet recommended by the German Nutrition Society (DGE).
Depending on their specific insulin therapy, patients may have more or less freedom in planning their meal plans. The most important factor is
- compensating for the lack of insulin in Type 1 or
- the reduced and delayed insulin action in Type 2
in such a way that blood glucose levels remain within the normal range after meals.
For people with diabetes who inject regular insulin, it is recommended to divide their food intake into three main meals and three snacks. Those who use insulin analogs, on the other hand, should eat only three meals a day to avoid extreme blood sugar fluctuations.
The chances of a cure depend on the specific type of diabetes. Type 1 diabetes is currently incurable because lost insulin-producing cells cannot be easily replaced. However, experts from the German Diabetes Society (DDG) see a new combination therapy as a promising approach.
Type 2 diabetes can be significantly alleviated—at least in the early stages of the disease—through consistent lifestyle changes. In some cases, further treatment with medication is no longer necessary.
To date, only gestational diabetes is completely curable. In this case, the woman’s body returns to normal after the birth of the child.
The goal of diabetes treatment is to
- minimize the risk of dangerous complications and
- enable those affected to enjoy a good quality of life.
Treatment for type 1 diabetes focuses on replacing the missing insulin. Type 2 diabetes can be significantly improved through weight loss, a healthy diet, and physical activity. If this is not sufficient, oral antidiabetic medications in tablet form or insulin therapy are indicated.
In patients with type 2 diabetes, elevated blood sugar levels are often accompanied by other cardiovascular risks such as
. These risks are taken into account in treatment. In many cases, a consistent change in diet helps manage gestational diabetes. If this is not sufficient, insulin therapy is also administered.
Diabetes is a complex disease with many forms, including type 1 diabetes and type 2 diabetes, which differ significantly in their causes and progression. In addition to these main forms, there are also various forms of diabetes mellitus, such as Type 3 or Onset Diabetes of the Young, which are less common. In autoimmune diabetes in particular, the cells in the pancreas are destroyed, whereas in other forms, the pancreas still produces insulin, but it is not effective enough.
Early diagnosis of diabetes is crucial to avoid high blood sugar levels and prevent complications of diabetes, such as diabetic foot syndrome. The treatment of diabetes, including diabetes mellitus, involves lifestyle changes, medication, or insulin injections, with insulin therapy being necessary for many patients. Gestational diabetes also poses a particular challenge and requires close monitoring.
In addition, there are special forms of diabetes and other types, such as maturity-onset diabetes of the young (MODY) or type 3 diabetes mellitus, which must be considered on a case-by-case basis. Causes may also include diabetes resulting from other diseases or induced diabetes. International organizations such as the American Diabetes Association, as well as publications such as *Lancet Diabetes Endocrinol*, provide important insights for modern diabetes therapy.
For patients with diabetes, continuous care is essential—for example, at a DDG Diabetes Center of Excellence—to achieve well-managed diabetes. The goal is to maintain quality of life and prevent long-term complications. Overall, it is clear that a proactive approach to managing the disease, regular checkups, and personalized treatments are crucial for minimizing the health impacts of diabetes.
What is diabetes mellitus?
Diabetes mellitus is a chronic metabolic disorder characterized by elevated blood sugar levels. It is caused by a lack of insulin or impaired action of the hormone insulin in the body’s cells.
What is the difference between Type 1 and Type 2 diabetes?
Type 1 diabetes is an autoimmune disease in which the insulin-producing cells in the pancreas are destroyed. Type 2 diabetes is usually caused by insulin resistance and obesity and is the most common form of diabetes mellitus.
How is diabetes diagnosed?
Diabetes is diagnosed based on blood glucose levels. High blood glucose levels may indicate type 2 diabetes mellitus or type 1 diabetes mellitus.
What treatment options are available for diabetes?
Depending on the type of diabetes, treatment may include a combination of diet, exercise, medication, or insulin injections. The goal is to lower blood sugar levels and prevent complications of diabetes.
What complications can diabetes cause?
Untreated diabetes can lead to diabetic complications such as nerve damage, kidney disease, or diabetic foot syndrome. That is why consistent treatment of diabetes mellitus is crucial.
