What Causes Diabetes? Unveiling the Roots of High Blood Sugar

Diabetes is a prevalent condition characterized by elevated blood sugar levels. This occurs when your body doesn’t effectively utilize glucose, a vital sugar that serves as the primary energy source for your cells, particularly in muscles, tissues, and the brain. Understanding What Causes Diabetes is crucial for prevention and management.

While the precise cause of diabetes varies depending on the type, the fundamental issue across all forms is an imbalance in blood sugar regulation. This can lead to hyperglycemia, a state of excess glucose in the bloodstream, which, if left unmanaged, can result in serious health complications.

Diabetes is broadly categorized into chronic forms like type 1 and type 2 diabetes, and potentially reversible conditions such as prediabetes and gestational diabetes. Prediabetes signifies a state where blood sugar levels are higher than normal but not yet in the diabetic range. It’s a critical stage because it can progress to type 2 diabetes without lifestyle interventions. Gestational diabetes, occurring during pregnancy, often resolves after childbirth but carries risks for both mother and child.

Understanding the Symptoms of Diabetes

Diabetes symptoms often correlate with the degree of blood sugar elevation. Notably, individuals with prediabetes, gestational diabetes, or type 2 diabetes might experience minimal or no noticeable symptoms, especially initially. In contrast, type 1 diabetes typically manifests with a rapid onset of more pronounced symptoms.

Common symptoms shared between type 1 and type 2 diabetes include:

Increased thirst (polydipsia)
Frequent urination (polyuria)
Unexplained weight loss
Presence of ketones in urine (ketonuria), indicating fat and muscle breakdown due to insufficient insulin
Fatigue and weakness
Irritability and mood changes
Blurred vision
Slow-healing sores or cuts
Recurrent infections, such as gum infections, skin infections, and vaginal yeast infections

Type 1 diabetes can emerge at any age but is frequently diagnosed in childhood or adolescence. Type 2 diabetes, the more common variant, can develop at any age, although it’s more prevalent after age 40. Alarmingly, type 2 diabetes is increasingly being diagnosed in children as well.

When to Seek Medical Advice

It’s crucial to consult a healthcare professional if you or your child exhibit any symptoms suggestive of diabetes. Early diagnosis is paramount for timely intervention and management. Furthermore, individuals already diagnosed with diabetes require ongoing medical follow-up to maintain stable blood sugar levels and prevent complications.

Delving into the Causes of Diabetes

To comprehend diabetes, it’s essential to first grasp the normal physiological processes of glucose utilization and insulin function within the body.

The Role of Insulin

Insulin, a hormone produced by the pancreas, plays a pivotal role in regulating blood sugar.

The pancreas secretes insulin into the bloodstream in response to rising glucose levels, typically after a meal.
Insulin acts like a key, enabling glucose to enter cells throughout the body for energy production.
This process effectively lowers blood sugar levels.
As blood glucose levels decrease, insulin secretion from the pancreas also diminishes, maintaining a delicate balance.

Glucose: The Body’s Fuel

Glucose, a simple sugar, is the body’s primary energy currency for cells, tissues, and organs.

Glucose originates from two main sources: dietary intake and the liver.
After digestion, glucose is absorbed into the bloodstream. Insulin facilitates its entry into cells.
The liver serves as a glucose reservoir, storing it as glycogen and also producing glucose.
When blood glucose levels dip, such as between meals or during fasting, the liver breaks down glycogen back into glucose, releasing it into the bloodstream to maintain stable energy supply.

In diabetes, this intricate glucose regulation system malfunctions. In most diabetes types, the root cause is the body’s inability to produce sufficient insulin or to use insulin effectively. This insulin deficiency or resistance leads to glucose accumulation in the bloodstream, the hallmark of diabetes. Both type 1 and type 2 diabetes are believed to arise from a complex interplay of genetic predispositions and environmental triggers, although the exact nature of these triggers remains under investigation.

Alt text: Woman meticulously checks her blood sugar levels using a glucometer, highlighting the proactive management of diabetes.

Risk Factors Associated with Diabetes

Diabetes risk factors are type-dependent, but family history is a significant factor across all types. For type 1 diabetes, environmental factors and geographical location may also contribute to risk.

Individuals with a family history of type 1 diabetes may undergo testing for diabetes-related autoantibodies – immune system cells that mistakenly attack the body’s own tissues. The presence of these autoantibodies indicates an elevated risk of developing type 1 diabetes, although not everyone with autoantibodies will develop the condition.

Race and ethnicity are recognized risk factors for type 2 diabetes. Certain populations, including Black, Hispanic, American Indian, and Asian American individuals, exhibit a disproportionately higher risk, although the underlying reasons are not fully understood.

Prediabetes, type 2 diabetes, and gestational diabetes are strongly linked to overweight and obesity. Excess body weight contributes to insulin resistance, a condition where cells become less responsive to insulin’s action, leading to elevated blood sugar levels.

Diabetes Complications: Long-Term Health Risks

Long-term diabetes complications develop gradually over time and are more likely and severe when blood sugar is poorly controlled. These complications can be debilitating and even life-threatening. Prediabetes itself is a significant risk factor for progressing to type 2 diabetes.

Potential diabetes complications encompass a wide range of health issues:

Cardiovascular Disease: Diabetes significantly elevates the risk of various cardiovascular problems, including coronary artery disease, angina (chest pain), heart attack, stroke, and atherosclerosis (narrowing of arteries). Heart disease and stroke are considerably more prevalent in individuals with diabetes.
Diabetic Neuropathy (Nerve Damage): Chronic high blood sugar can damage the capillaries that supply nerves, particularly in the extremities. This can manifest as tingling, numbness, burning pain, typically starting in the toes or fingers and progressing upwards. Nerve damage can also affect digestion, causing nausea, vomiting, diarrhea, or constipation. In men, it can lead to erectile dysfunction.
Diabetic Nephropathy (Kidney Damage): The kidneys contain glomeruli, intricate networks of blood vessels that filter waste. Diabetes can impair this delicate filtration system, potentially leading to kidney failure.
Diabetic Retinopathy (Eye Damage): Diabetes can damage blood vessels in the retina, the light-sensitive tissue at the back of the eye. This can lead to vision impairment and even blindness if left untreated.
Foot Complications: Nerve damage and impaired blood flow to the feet increase the risk of foot ulcers, infections, and even amputation.
Skin and Mouth Conditions: Diabetes can increase susceptibility to skin problems, including bacterial and fungal infections. Gum disease is also more common.
Hearing Impairment: Hearing problems are more frequently observed in people with diabetes.
Alzheimer’s Disease: Type 2 diabetes is associated with an increased risk of dementia, including Alzheimer’s disease.
Depression: Symptoms of depression are common in individuals with both type 1 and type 2 diabetes, highlighting the mental health burden of this chronic condition.

Alt text: A doctor utilizes an anatomical model to explain the complexities of diabetes to a patient, emphasizing patient education in diabetes management.

Complications of Gestational Diabetes

While most women with gestational diabetes deliver healthy babies, uncontrolled blood sugar during pregnancy can pose risks for both mother and child.

For the baby, complications can include:

Macrosomia (Excessive Growth): Excess glucose crosses the placenta, stimulating the baby’s pancreas to produce extra insulin, which can lead to excessive fetal growth and birth complications, sometimes requiring Cesarean delivery.
Hypoglycemia (Low Blood Sugar) at Birth: Due to high insulin production in utero, newborns may experience hypoglycemia shortly after birth.
Increased Risk of Type 2 Diabetes Later in Life: Children born to mothers with gestational diabetes have a higher risk of developing obesity and type 2 diabetes in adulthood.
Stillbirth: Untreated gestational diabetes can, in severe cases, lead to fetal death before or shortly after birth.

For the mother, complications can include:

Preeclampsia: This pregnancy complication is characterized by high blood pressure, protein in the urine, and edema (swelling), posing risks to both mother and baby.
Recurrence of Gestational Diabetes in Future Pregnancies: Women who have had gestational diabetes in one pregnancy are at higher risk of developing it again in subsequent pregnancies.

Preventing Diabetes: Lifestyle Strategies

While type 1 diabetes is not preventable, the healthy lifestyle choices that are crucial for managing prediabetes, type 2 diabetes, and gestational diabetes can also be highly effective in preventing these conditions.

Healthy Eating: Emphasize a diet rich in fruits, vegetables, and whole grains. Choose foods low in saturated and trans fats, added sugars, and calories. Dietary fiber is particularly beneficial for blood sugar control. Variety in food choices helps maintain long-term adherence to a healthy eating pattern.
Regular Physical Activity: Aim for at least 150 minutes of moderate-intensity aerobic exercise per week, such as brisk walking. Even short bursts of activity throughout the day are beneficial if a longer workout is not feasible.
Weight Management: For individuals who are overweight or obese, losing even a modest amount of weight (around 7% of body weight) can significantly reduce diabetes risk. However, weight loss is generally not recommended during pregnancy; pregnant women should consult their healthcare provider for healthy weight gain recommendations. Focus on sustainable lifestyle changes for long-term weight management and overall health benefits.

In certain high-risk individuals, medications like metformin may be considered to reduce the risk of type 2 diabetes. However, lifestyle modifications remain the cornerstone of diabetes prevention. If you have prediabetes, regular blood sugar monitoring (at least annually) is essential to detect progression to type 2 diabetes early.

By Mayo Clinic Staff

Diabetes care at Mayo Clinic

Request an appointment

Diagnosis & treatment

March 27, 2024

References:

Ferri FF. Diabetes mellitus. In: Ferri’s Clinical Advisor 2022. Elsevier; 2022. https://www.clinicalkey.com. Accessed May 7, 2022.
Classification and diagnosis of diabetes: Standards of medical care in diabetes — 2022. Diabetes Care. 2022; doi:10.2337/dc22-S002.
Papadakis MA, et al., eds. Diabetes mellitus. In: Current Medical Diagnosis & Treatment 2022. 61st ed. McGraw Hill; 2022. https://accessmedicine.mhmedical.com. Accessed May 4, 2022.
Diabetes risk factors. Centers for Disease Control and Prevention. https://www.cdc.gov/diabetes/basics/risk-factors.html. Accessed June 2, 2022.
Cunningham FG, et al. Diabetes mellitus. In: Williams Obstetrics. 25th ed. McGraw-Hill Education; 2018. https://accessmedicine.mhmedical.com. Accessed June 2, 2022.
Diabetes and DKA (ketoacidosis). American Diabetes Association. https://www.diabetes.org/diabetes/dka-ketoacidosis-ketones. Accessed May 4, 2022.
Diabetes Canada Clinical Practice Guidelines Expert Committee. Complementary and alternative medicine for diabetes. Canadian Journal of Diabetes. 2018; doi:10.1016/j.jcjd.2017.10.023.
Nimmagadda R. Allscripts EPSi. Mayo Clinic. June 16, 2022.
Jameson JL, et al., eds. Diabetes mellitus: Diagnosis, classification and pathophysiology. In: Harrison’s Principles of Internal Medicine. 20th ed. McGraw-Hill Education; 2018. https://accessmedicine.mhmedical.com. Accessed June 2, 2022.
Pharmacologic approaches to glycemic treatment: Standards of medical care in diabetes — 2022. Diabetes Care. 2022; doi:10.2337/dc22-S009.
Facilitating behavior change and well-being to improve health outcomes: Standards of medical care in diabetes — 2022. Diabetes Care. 2022; doi:10.2337/dc22-S005.
AskMayoExpert. Type 1 diabetes mellitus. Mayo Clinic; 2021.
Glycemic targets: Standards of Medical Care in diabetes — 2022. Diabetes Care. 2022; doi:10.2337/dc22-S012.
Comprehensive medical evaluation and assessment of comorbidities: Standards of Medical Care in Diabetes — 2022. Diabetes Care. 2022; doi:10.2337/dc22-S004.
Prevention or delay of type 2 diabetes and associated comorbidities: Standards of Medical Care in diabetes — 2022. Diabetes Care. 2022; doi:10.2337/dc22-S003.
Obesity and weight management for the prevention and treatment of type 2 diabetes: Standards of Medical Care in Diabetes — 2022. Diabetes Care. 2022; doi:10.2337/dc22-S008.
Diabetes technology. Standards of Medical Care in Diabetes — 2022. 2022; doi:10.2337/dc22-S007.