Diabetes mellitus is a group of diseases that affect how the body uses glucose. Glucose is vital for the body because it is the primary source of energy for the cells that make up muscles and tissues. Glucose, or sugar, is also the main fuel for the human brain.

Glucose enters the body from two main sources: food and reserves stored in the liver. When we haven’t eaten for a while, the liver breaks down stored glycogen into glucose to provide energy. Once glucose enters the bloodstream from the intestines or liver, it enters the cells with the help of the hormone insulin. Insulin is produced by specialized cells in the pancreas and is released into the blood in response to the amount of carbohydrates consumed.

It’s important to note that “sugar” shouldn’t only be understood as the crystalline substance we use to sweeten various foods and beverages. Any carbohydrate-containing food ultimately contains sugars, such as bread, fruits, vegetables, and so on. When insulin enters the bloodstream, it reduces the amount of sugar in the blood by “transporting” it into the cells.


Regardless of the type of the disease, the main consequence is an elevated level of glucose in the blood plasma. Chronically elevated blood sugar levels have been proven to lead to serious health problems. The most severe impairments affect the nerves, nerve endings, and blood vessels, ranging from the smallest arterioles to the largest arteries.

There are also potentially reversible conditions of the disease, known as prediabetes, where the blood sugar level is higher than normal but not elevated enough to be classified as a developed disease, and gestational diabetes, which occurs during pregnancy but may disappear after giving birth.

The normal values of blood glucose depend on several factors:
  • Depending on a person’s age. There are differences in normal values for infants, adults, and the elderly – over 80-85 mg/dL.
  • Whether the sample is taken fasting or after a meal.
  • If taken after a meal, the specific food consumed and the time elapsed since eating.
  • Whether the blood is drawn from a vein or from a capillary (from the finger).
normal values of blood glucose
Different laboratories may have varying reference (normal) values, but the most commonly accepted values are as follows:
  • Fasting blood glucose in the serum: 3.9 to 6.1 mmol/L
  • Capillary blood glucose: 3.5 to 5.5 mmol/L
  • Postprandial blood glucose in the serum: up to 7.7 mmol/L
  • Newborns up to 1 month old (fasting): 2.8 to 4.4 mmol/L
  • Children aged 1 month to 14 years (fasting): 3.3 to 5.6 mmol/L
  • Individuals over 85-90 years old (fasting): 4.2 to 6.7 mmol/L
The chronic phase of the disease includes two types: type 1 and type 2.

Type 1 diabetes (Insulin-dependent): For unknown reasons, the immune system sometimes attacks and destroys the pancreatic cells that produce insulin. This leads to a deficiency or complete absence of insulin. Consequently, the sugar obtained from food cannot enter the cells and tissues, resulting in high levels of sugar in the blood. It is called “insulin-dependent” because the disease is directly related to the lack of sufficient insulin, and patients must inject this hormone in order to survive.

Type 1 diabetes (Insulin-dependent)
Type 1 diabetes can develop at any age, although it primarily manifests in childhood or adolescence.

Risk factors for the development of insulin-dependent diabetes include:

  • Family history – if a parent, sibling, or sibling is affected, your risk increases.
  • Certain viral infections can inappropriately activate the immune system, leading to an attack on insulin-producing cells in the pancreas.
  • Presence of specific antibodies – autoantibodies. Some individuals in families with type 1 diabetes have been found to have specific autoantibodies, indicating an increased risk of developing the disease. However, not everyone with these autoantibodies will develop the disease.

Being overweight is not considered a risk factor for this type of diabetes.

Type 2 Non insulin dependent diabetes
Non-insulin dependent diabetes (Type 2):

In this type, cells become resistant (insensitive) to the action of insulin, even though initially the body produces it in sufficient quantities. To overcome this resistance, the pancreas attempts to produce more insulin, but ultimately the gland becomes exhausted without compensating for the condition. As a result, instead of entering cells for their needs, sugar accumulates in the blood in excessive amounts.

The exact causes of insulin resistance in cells are not established. Scientists believe it is a combination of genetic factors and environmental factors.

Risk factors for the development of Type 2 diabetes include:

  • It has been firmly established that being overweight is strongly associated with the development of diabetes. The fat tissues present in the body, the more resistant the tissues are to insulin. However, not everyone with this condition is overweight.
  • Sedentary lifestyle. The less active a person is, the greater the risk. Physical activity helps control weight because glucose from food is used as energy rather than stored as fat. Additionally, physical exertion makes cells more sensitive to insulin.
  • Family history. The risk increases if a parent or sibling has Type 2 diabetes.
  • It is still unclear why, but individuals from certain races, such as Black, Hispanic, Native American, and Asian-American populations, are at a higher risk.
  • The risk increases with advancing age. One of the reasons is the tendency for many older individuals to have limited mobility, muscle loss, and weight gain. However, in recent decades, the disease has become more common in children and young adults. This is associated with poor dietary habits, sedentary lifestyle, and obesity in the youth population. If you have developed gestational diabetes during pregnancy, the risk of developing prediabetes and Type 2 diabetes later in life increases.
  • Polycystic ovary syndrome. For women who have this commonly occurring condition characterized by irregular menstrual cycles, excessive hair growth, and obesity, the risk is higher.
  • Uncontrolled chronic high blood pressure above 139/89 mm Hg is associated with an increased risk of Type 2 diabetes.
  • High levels of total and “bad” LDL cholesterol, as well as triglycerides, and low levels of “good” HDL cholesterol are associated with an increased risk of non-insulin dependent diabetes.

Initially, complaints are due to high levels of blood sugar in the bloodstream. It is not uncommon for the disease to be discovered only when it causes complications such as a heart attack, stroke, or slow-healing wounds. Typically, the symptoms vary depending on how high the blood sugar rises. In Type 1 diabetes, symptoms often appear quickly and are more severe, while Type 2 diabetes can go undetected for a long time.

Main symptoms for both types of diabetes include:

  • Increased thirst and the need for increased fluid intake
  • Frequent urination
  • Episodes of extreme hunger
  • Unexplained weight loss despite no change in eating habits
  • Unusual fatigue
  • Irritability
  • Blurred vision
  • Slow-healing wounds
  • Persistent itching throughout the body
  • Predisposition to frequent infections, such as skin, gum, or genital infections
When is the diagnosis of diabetes made?
diagnosis of diabetes

The most reliable way is the laboratory measurement of glucose in the blood:

  • Random blood sugar test: If blood sugar is found to be above 11.1 mmol/L regardless of the last meal, including after fasting, it is diagnosed as diabetes.
  • Fasting blood sugar test: A result between 6.1 to 6.9 mmol/L is considered prediabetes, while a result above 7 mmol/L in two separate tests indicates diabetes.
  • Oral glucose tolerance test: In this test, blood sugar is measured after fasting in the morning, then approximately 200 milliliters of liquid containing 75 grams of glucose is consumed. Blood is taken again after half an hour, one hour, and two hours. The main and most important results are obtained at the two-hour mark. If the blood sugar is measured below 7.8 mmol/L at that time, the result is normal. Impaired glucose tolerance is diagnosed with results between 7.8 and 11 mmol/L, and diabetes is diagnosed above 11.1 mmol/L.
  • Glycated haemoglobin (A1C) test: This blood test does not require fasting. It shows the average level of blood sugar over the past two to three months. It measures the percentage of blood sugar bound to haemoglobin in the blood. The higher the levels of blood sugar in the serum, the more glucose will be bound to haemoglobin. When glycated haemoglobin is above 6.5% in two separate tests, the disease is present. A result between 5.7 and 6.4% indicates prediabetes. Values below 5.7% are considered normal.
  • Urine analysis: Increased levels of ketones, which are a byproduct when muscle and fat tissues are used for energy when the body lacks sufficient insulin to use available glucose, can be detected in the urine. Additionally, the presence of sugar in the urine, which is not typical for healthy individuals, can be identified.
Gestational Diabetes

This is a specific health condition that affects some women during pregnancy who have not previously been diagnosed with diabetes. Gestational diabetes should not be confused with pre-existing diabetes that was present before pregnancy and was undiagnosed.

During pregnancy, the placenta produces specific hormones to support the pregnancy. These hormones can make cells more resistant to insulin. Normally, the pancreas responds by producing enough additional insulin to overcome this resistance. However, sometimes the pancreas cannot cope with the increased demand. When this happens, too little glucose enters the cells, and too much remains in the blood, leading to gestational diabetes. In many cases, this condition disappears after childbirth and does not require any treatment.

Women who are at a higher risk of developing this condition include:

  • Age over 25 years
  • Pre-existing prediabetes – a precursor to non-insulin-dependent diabetes
  • Family history – a parent or sibling with type 2 diabetes
  • Previous history of gestational diabetes or delivering a large baby in a previous pregnancy
  • Previously unexplained stillbirth
  • Overweight or obesity

Possible complications of diabetes:

  • Acute Complications: In the past, people with diabetes most commonly died from acute complications of the disease. These complications occur when, due to lack of insulin, glucose cannot enter the cells, leaving them without energy. The body then resorts to “emergency fuel” by breaking down proteins and fats. However, this leads to a significant acidification of the blood called “diabetic ketoacidosis.” It presents with nausea, vomiting, a smell of acetone in the mouth and sweat, and abdominal pain. Without timely medical intervention, it can progress to coma and death.

In modern times, very few patients reach this condition, primarily if they are unaware, they are sick or have missed their insulin doses. Diabetic ketoacidosis is a life-threatening emergency that requires immediate medical intervention.

  • Chronic Complications: These complications develop gradually and over the years become the cause of disability and premature death for many people with poorly controlled diabetes.

The good news is that with proper treatment and a comprehensive lifestyle approach, these patients can live long lives with a preserved quality of life. The longer the duration of the disease and the poorer the control of blood sugar, the greater the risk of complications.

  • Cardiovascular diseases: Medicine now considers diabetes as a cardiovascular disease because it dramatically increases the risk of various complications, including ischemic heart disease, myocardial infarction, stroke, generalized atherosclerosis, arrhythmias, peripheral vascular disease, and vascular occlusion in internal organs such as the intestines and kidneys.
  • Peripheral neuropathy: Elevated blood sugar damages the walls of small blood vessels (arterioles and capillaries) that supply blood to nerve endings throughout the body. As a result, the nerves start to function inefficiently, causing numbness, burning sensation, or pain that usually begins in the toes and progresses upwards over time. This condition is known as diabetic polyneuropathy. It can affect not only the extremities but also internal organs, which become less efficient.
  • Diabetic foot: Reduced sensitivity in the extremities and poor tissue nourishment in diabetes lead to chronic foot ulcers. In some patients, these ulcers can progress to such an extent that amputation becomes necessary.
  • Renal impairment (diabetic nephropathy): The kidneys contain millions of tiny clusters of blood vessels (glomeruli) that filter waste products from the blood. High blood sugar can damage this delicate filtration system. In severe cases, it can lead to kidney failure, which in its end stages requires haemodialysis or kidney transplantation.
  • Eye complications (diabetic retinopathy): Diabetes often damages the blood vessels of the retinas, potentially leading to blindness. The disease also increases the risk of cataracts and glaucoma.
  • Erectile dysfunction (impotence): This condition occurs due to the involvement of blood vessels supplying the penis and the impairment of nerves involved in the erection mechanism.
  • Dementia: Diabetes can increase the risk of dementia, including Alzheimer’s disease. The risk is greater with poorer blood sugar control. The exact relationship between these conditions is still not fully understood, but medical statistics have established the connection.


One of the complications during treatment is excessively low blood sugar levels. This most commonly occurs in patients taking insulin, but it can also happen in individuals on oral therapy.

Symptoms of hypoglycaemia include weakness, trembling, sweating, pallor, nausea, and blurred vision. Every patient should be familiar with this condition and take fast-acting carbohydrates such as sugar, glucose syrup, honey, etc., at the onset of symptoms. Severe hypoglycaemia can lead to permanent damage and even death.

Treatment of diabetes:
Treatment of diabetes

A definitive cure for diabetes is still unknown. However, with proper disease management, the quality and duration of life can be comparable to those without the condition.

Normalizing blood sugar levels is mandatory but not sufficient. Recent studies have found that the most important goal of treating this disease is comprehensive intervention to reduce cardiovascular risk and prevent acute and chronic complications.

Modern treatment includes the following measures:
  • Regular blood sugar control in laboratories and at home.
  • Periodic monitoring of other blood parameters indicating the status of the liver, kidneys, cholesterol fractions, uric acid, and proteins.
  • Regular checking and control of blood pressure and heart rate (pulse).
  • Rational nutrition.
  • Weight control.
  • Regular and age-appropriate physical activity considering other illnesses and general condition.
  • Seeking psychological comfort through hobbies and social contacts.
  • Medication therapy (tablets and/or insulin).
  • Nutritional supplements and herbs.
  • Medication therapy:

In type 1 diabetes, insulin treatment is most commonly required, which serves as a substitute therapy. Type 2 diabetes is often managed with oral medications (tablets), but some patients may require insulin supplementation.

The fear of starting insulin treatment is completely unjustified. Modern forms of this medication are highly precise, with different types of insulin available, including rapid-acting, long-acting, mixed, and others, which closely match patients’ needs.

One concern with this life-saving medication, used for millions of people since its discovery, is that it is administered by injection. The reason for this is that it gets destroyed in the digestive system and cannot reach the bloodstream in an active form. However, injection is made convenient and effective through insulin pens, which allow for strict dosing and minimal discomfort.

There are various types of tablets available that improve the impaired glucose metabolism through different mechanisms. Some stimulate the pancreas to produce more insulin, while others block sugar production in the liver. Some medications act within the digestive system, inhibiting carbohydrate breakdown. There are also medications that increase tissue sensitivity to insulin.

In the global medical context, the first medication prescribed for diabetes is metformin. It can also be used for preventing the progression of the condition in patients with prediabetes and metabolic syndrome. Metformin is one of the most commonly prescribed medications.

New medications In clinical practice, there are now medications (SGLT-2 inhibitors) that not only effectively lower blood sugar but also successfully control and reduce cardiovascular risk. These medications are prescribed to patients whom the doctor deems at risk for cardiovascular incidents. Their mechanism of action is related to the elimination of excess sugar from the blood through the kidneys and urine. This also reduces the overall volume of fluids in the body and, consequently, lowers blood pressure.

Insulin pumps High-tech devices about the size of a mobile phone that can be programmed to deliver the required amount of insulin based on factors such as meals, physical activity, and other criteria.

A look into the future of diabetes
  • Artificial pancreas: a device that continuously measures blood sugar levels and automatically delivers the necessary amount of insulin into the bloodstream. It is still under development and undergoing clinical trials.
  • Pancreas transplantation: Numerous attempts have been made, with many successful cases, particularly for type 1 diabetes. However, even successful transplantation has its drawbacks. Patients need to take medications for the rest of their lives to suppress organ rejection, and these medications may have serious side effects.

The role of nutritional supplements Various substances and herbs have been studied to determine if they can lower blood sugar levels and their role in patients with similar conditions. Currently, there is no scientific evidence that herbs or nutritional supplements alone can control the disease. However, this does not mean they have no place in a comprehensive approach to managing the condition. It is important to consider not only blood sugar levels but also how other risk factors are controlled.

Products containing alpha-lipoic acid have been shown to have a proven positive effect in protecting nerve endings from damage due to high blood sugar. Its intake serves as prevention and treatment for one of the most common complications, diabetic polyneuropathy.

Cinnamon can sometimes help in controlling blood sugar. Studies have shown that individuals regularly consuming cinnamon have lower glycated hemoglobin levels under similar conditions.

Any other herbs and supplements that reduce the degree of “silent inflammation” in the body and lower oxidative stress can be beneficial.

Consult your doctor about taking additional substances to ensure they do not interact with your primary treatment.

How to eat with diabetes The rules for healthy eating are valid for everyone, regardless of whether they have diabetes or not. The time of absolute prohibitions is over. If you have a strong craving for sweets, don’t deprive yourself, but limit it to occasional indulgences and, to compensate, reduce your intake of other carbohydrates, such as bread. It is important that your diet is balanced and contains everything necessary for the proper functioning of the body.

Recommended foods: Fruits and vegetables are a must. Prefer raw or steamed vegetables. Carbohydrate-containing foods, which are sources of sugar, can be divided into those that contain “fast” and “slow” carbohydrates. The former lead to a rapid increase in blood glucose, which the body has difficulty managing.

These include foods and drinks with refined sugar, honey, white flour products, sweet grapes, and bananas. Prefer “slow” carbohydrates such as whole-grain bread and pasta, brown rice, and unprocessed oats. Choose lean meat options without visible fat, such as chicken breasts, lean pork, and lamb.

Fish is particularly recommended, but avoid frying and opt for baking or grilling: mackerel, salmon, sea bass. Nuts and legumes are valuable sources of protein. Dairy products are a good option for meals, but avoid sweetened yogurts and fresh milk.

Modern treatment of diabetes

Not only for high blood sugar, but for every individual, it is not recommended to consume:

  • Sweetened and carbonated beverages
  • Fruit preserves and sugary fruit juices
  • Packaged foods like waffles, chips, snacks, etc.
  • Fast food items such as hamburgers, french fries, pizza slices, doughnuts.
Is prevention of diabetes possible?

Currently, there is no specific method identified by science to prevent insulin-dependent diabetes. Inheritance plays a significant role in this condition.

However, even in individuals predisposed to type 2 diabetes, lifestyle choices can delay or even prevent the onset of the disease.

The primary factors for prevention include:

  • Maintaining a normal body weight, even a few kilograms below the average weight for one’s gender, height, and age.
  • Engaging in moderate physical activity, such as exercising for 30 minutes per day, which slightly raises the heart rate to around 120 beats per minute.
  • Adopting sensible eating habits: having breakfast, lunch, and dinner without snacks in between, except for fruits or vegetables. Avoiding sweetened, carbonated, and concentrated foods. Increasing the consumption of whole grains, legumes, nuts, fish, olive oil, and lean meats. Having at least two days per week without meat and dairy products.
  • Keeping blood pressure within the normal range.
  • Developing strategies to manage stress through activities that promote relaxation and divert attention from stressful professional or other activities.
Is diabetes fatal?

In the past, patients would often die shortly after experiencing diabetic ketoacidosis. However, with the discovery of insulin and other medications, survival rates have significantly improved.

Today, the main concern lies in chronic complications that can reduce life expectancy and diminish its quality. Most individuals with diabetes succumb to cardiovascular complications such as heart attacks, strokes, pulmonary embolism, and other acute circulatory disorders. Kidney damage is also a significant issue.