Insulin is a hormone that helps glucose move from the bloodstream into the body's cells, where it is used for energy. When this process does not work properly, glucose builds up in the blood. Persistently high blood glucose can damage blood vessels and nerves and eventually affect the heart, kidneys, eyes, and other organs.
According to the World Health Organization (WHO), the number of people living with diabetes increased from about 200 million in 1990 to 830 million in 2022. More than 95% of people with diabetes have type 2 diabetes.
Understanding diabetes, its warning signs, and how it is managed can help prevent or delay serious complications.
What is Diabetes?
Glucose is the body's main source of energy. It comes largely from the carbohydrates in food and enters the bloodstream after digestion.
Insulin, produced by the pancreas, allows glucose to move from the blood into cells. In diabetes, either the body does not make enough insulin or the cells do not respond properly to it.
As a result, glucose remains in the bloodstream, causing high blood sugar, also known as hyperglycaemia.
A short-term rise in blood sugar after eating is normal. Diabetes involves persistently abnormal blood glucose levels.
If high blood sugar continues for years, it can damage blood vessels and nerves. This is why diabetes is not simply a condition involving sugar in the diet. It is a metabolic disorder that can affect almost every major organ system.
What Are The Main Types Of Diabetes?
According to the Centers for Disease Control and Prevention (CDC), there are several types of diabetes, but type 1, type 2, and gestational diabetes are the most commonly discussed.
Type 1 Diabetes
Type 1 diabetes is an autoimmune condition. The immune system mistakenly attacks the insulin-producing cells in the pancreas, resulting in little or no insulin production.
People with type 1 diabetes need insulin every day to survive. It can develop at any age, although it is particularly common in children and young adults.
Unlike type 2 diabetes, type 1 diabetes cannot currently be prevented through lifestyle changes. Its exact cause is not fully understood.
Symptoms can appear quickly, sometimes over days or weeks. They may include excessive thirst, frequent urination, increased hunger, unexplained weight loss, and extreme tiredness.
Type 2 Diabetes
Type 2 diabetes is the most common form.
In the early stages, the body may still produce insulin but does not use it effectively. This is known as insulin resistance. Over time, the pancreas may struggle to produce enough insulin to compensate.
Type 2 diabetes is influenced by several factors, including genetics, age, excess weight and low physical activity. It can occur in younger people as well as older adults.
Unlike type 1 diabetes, many cases of type 2 diabetes can be prevented or delayed through healthy lifestyle changes.
Gestational Diabetes
Gestational diabetes develops during pregnancy when blood glucose levels become higher than normal but do not meet the criteria for diabetes outside pregnancy.
It can increase the risk of complications during pregnancy and delivery. Women who have had gestational diabetes also have a higher future risk of developing type 2 diabetes, while their children may also have a higher risk.
Gestational diabetes is generally detected through testing during pregnancy because it may not cause obvious symptoms.
What Are The Symptoms Of Diabetes?
Diabetes does not always cause noticeable symptoms, particularly type 2 diabetes. Some people may have high blood sugar for years without knowing it.
Common symptoms include:
- Excessive thirst
- Frequent urination
- Increased hunger
- Unexplained weight loss
- Persistent tiredness
- Blurred vision
- Slow healing of wounds
- Repeated infections
Type 1 diabetes tends to cause symptoms more quickly and can become serious within a short period.
Type 2 diabetes can develop much more gradually. Some people are diagnosed only after routine blood tests or when a diabetes-related complication develops.
What Causes Type 2 Diabetes?
There is no single cause of type 2 diabetes. It develops through an interaction between genetics, biology, and lifestyle factors.
Having excess body fat, particularly around the waist, can increase insulin resistance. Low levels of physical activity can also contribute to the risk.
Age and family history are important factors too. Having a close relative with type 2 diabetes can increase your risk.
However, being slim does not completely protect someone from type 2 diabetes. Genetic susceptibility and other metabolic factors can also contribute.
Type 2 diabetes is therefore not simply the result of eating too much sugar. Diet is important, but the condition involves several interacting factors.
What Is Prediabetes?
Prediabetes means that blood glucose is higher than the normal range but not yet high enough to meet the criteria for diabetes.
It is an important warning stage because people with prediabetes have an increased risk of developing type 2 diabetes. However, progression is not inevitable.
Lifestyle changes can help reduce this risk, particularly when they include regular physical activity, a healthier diet, and weight management where appropriate.
How is Diabetes Diagnosed?
According to the American Diabetes Association, diabetes is diagnosed using blood glucose tests rather than symptoms alone.
Common tests for blood sugar include:
HbA1c
The HbA1c test gives an estimate of average blood glucose over approximately the previous two to three months.
For non-pregnant adults, an HbA1c level of 6.5% or above is one of the accepted diagnostic criteria for diabetes.
Fasting blood glucose
This measures blood glucose after at least eight hours without food.
A fasting plasma glucose level of 126 mg/dL (7.0 mmol/L) or above meets the diagnostic threshold for diabetes.
Oral glucose tolerance test
During an oral glucose tolerance test, blood glucose is measured before and after consuming a glucose-containing drink.
A two-hour glucose level of 200 mg/dL (11.1 mmol/L) or above meets the diagnostic threshold.
Random blood glucose
A random plasma glucose level of 200 mg/dL (11.1 mmol/L) or above, together with classic symptoms of high blood sugar or a hyperglycaemic crisis, can also support a diagnosis.
When there is no clear evidence of severe hyperglycaemia, an abnormal result generally needs confirmation according to the diagnostic approach being used.
How Is Diabetes Treated?
Treatment depends on the type of diabetes, blood glucose levels, other health conditions and individual needs.
Type 1 diabetes
People with type 1 diabetes need insulin replacement. It can be given through injections or an insulin pump.
Blood glucose monitoring is an important part of treatment because insulin doses need to be matched to factors such as food, activity and blood glucose levels.
Type 2 diabetes
Treatment may include changes to eating habits, physical activity, weight management, blood glucose monitoring and medicines.
Medicines can include tablets and injectable treatments. Metformin is commonly used, while other medicines may be selected according to a person's blood glucose levels, cardiovascular health, kidney function, weight and other factors.
Some people with type 2 diabetes eventually need insulin, particularly when the pancreas can no longer produce enough insulin.
Diabetes treatment is not the same for everyone, so medicines should be prescribed and adjusted by a healthcare professional.
Importance of Diet for Diabetes Management
Having diabetes does not mean that you must completely stop eating carbohydrates or avoid every food containing sugar.
Instead, the overall quality and quantity of food matter.
A diabetes-friendly eating pattern generally focuses on vegetables, pulses, whole grains, nuts, seeds, suitable protein sources and minimally processed foods. Portions of carbohydrate-rich foods may need to be considered because carbohydrates have the greatest direct effect on blood glucose.
Sugary drinks, sweets and highly processed foods are best limited.
Regular meal patterns may also make blood glucose management easier for some people, particularly when taking certain diabetes medicines.
A diet plan should be personalised, especially for people taking insulin or medicines that can cause low blood sugar.
Exercise And Diabetes
Physical activity helps the body use glucose more effectively and can improve insulin sensitivity.
Regular activity can include walking, cycling, swimming, strength training or other activities that a person can perform safely.
The WHO recommends at least 150 minutes of moderate physical activity a week for the prevention of type 2 diabetes, alongside other healthy lifestyle measures.
People with diabetes should choose activities appropriate for their health and fitness level. Those taking insulin or certain glucose-lowering medicines may need to take additional precautions to prevent low blood sugar during or after exercise.
What Is Low Blood Sugar?
While high blood sugar is a major concern in diabetes, blood glucose can sometimes become too low, particularly in people using insulin or certain medicines.
Low blood sugar, or hypoglycaemia, can cause:
- Shaking
- Sweating
- Hunger
- Dizziness
- Irritability
- Fast heartbeat
- Confusion
- Difficulty concentrating
Severe hypoglycaemia can cause seizures or loss of consciousness and requires urgent treatment.
Anyone using insulin or medicines that can cause hypoglycaemia should learn how to recognise and manage low blood sugar.
What Happens When Blood Sugar Remains High?
Persistently high blood glucose can gradually damage blood vessels and nerves.
This can affect several parts of the body.
Heart And Blood Vessels: Diabetes increases the risk of cardiovascular disease, including heart attacks and strokes. High blood pressure and abnormal cholesterol levels often occur alongside diabetes and can further increase cardiovascular risk.
Kidneys: The kidneys filter waste from the blood. Damage to their small blood vessels can lead to diabetic kidney disease.
Early kidney damage may cause no symptoms, which is why regular testing is important for people with diabetes.
Eyes: Diabetes can damage the blood vessels in the retina, causing diabetic retinopathy.
If it progresses without treatment, it can lead to vision loss and blindness.
Nerves: High blood sugar can damage nerves, particularly those in the feet and legs.
Symptoms may include tingling, burning, numbness or pain. Reduced sensation can make it easier to miss cuts, blisters or other injuries.
Feet: Nerve damage and reduced blood flow can make foot wounds harder to heal. An untreated ulcer can become infected and, in severe cases, lead to amputation.
Regular foot checks are therefore an important part of diabetes care.
Why Regular Health Checks Matter
Managing diabetes is about more than checking blood sugar. People with diabetes may need regular monitoring of:
- HbA1c and blood glucose
- Blood pressure
- Cholesterol
- Kidney function
- Urine for signs of kidney damage
- Eye health
- Foot health
- Body weight and overall cardiovascular risk
Regular checks can identify complications at an early stage, when treatment may prevent them from becoming more serious.
WHO recommends regular screening and treatment for diabetes-related complications, including damage to the eyes, kidneys and feet.
Can Type 2 Diabetes Be Prevented?
Type 2 diabetes cannot always be prevented because genetics and age also influence risk. However, many cases can be prevented or delayed.
Helpful measures include:
- Maintaining a healthy weight where appropriate
- Being physically active regularly
- Eating a balanced diet
- Choosing more whole foods and high-fibre foods
- Limiting foods high in added sugar and saturated fat
- Avoiding tobacco
- Managing blood pressure and cholesterol
These measures are also beneficial for heart health.
People with a higher risk of type 2 diabetes may benefit from regular blood glucose testing, particularly if they have a family history, excess weight or a previous history of gestational diabetes.
Can Diabetes Be Cured?
At present, there is no general cure for type 1 diabetes, and people with the condition require insulin.
Type 2 diabetes is also generally considered a chronic condition. However, some people can achieve remission, meaning their blood glucose returns below the diabetes range without glucose-lowering medication for a period of time.
This does not mean the underlying susceptibility has disappeared. Blood glucose can rise again, so continued monitoring and healthy habits remain important.
Treatment goals should therefore focus on maintaining healthy blood glucose levels and reducing the risk of complications rather than relying on claims of a permanent cure.
When To See A Doctor?
You should seek medical advice if you have symptoms such as excessive thirst, frequent urination, unexplained weight loss, persistent tiredness or blurred vision.
People without symptoms may also need testing if they have risk factors for diabetes.
Urgent medical attention is needed for severe symptoms of very high or very low blood sugar, particularly confusion, loss of consciousness, severe dehydration, vomiting or difficulty breathing.
Final Word
Diabetes is a long-term condition that affects how the body controls blood glucose. Although type 2 diabetes is the most common form, type 1 and gestational diabetes have different causes and treatment needs. The condition can sometimes remain silent, particularly in its early stages. Early diagnosis and appropriate treatment are therefore important. With appropriate care, many diabetes-related complications can be prevented or delayed. The goal is not simply to control a blood sugar number, but to protect the health of the whole body over the long term.
