Silent Enemy: How Insulin Resistance Leads to Diabetes

Insulin resistance is a term that has gained tremendous popularity among the general public over the past 10 years and is frequently mentioned by nutritionists, gynecologists, endocrinologists, dietitians, and even fitness coaches. This condition can develop for years without noticeable symptoms, and the first characteristic signs are often consciously ignored. The person may feel relatively well, lab results remain close to normal, yet metabolic disturbances are already forming in the body, capable of leading to type 2 diabetes, cardiovascular diseases, and fatty liver disease.
It is truly a “silent enemy” that develops gradually and unnoticed. For this reason, the condition is often detected only at the stage of prediabetes or diabetes.

Insulin Resistance – When Cells Stop “Listening” to Insulin

Insulin resistance is a decrease in the sensitivity of the body’s cells to insulin.
Insulin is a hormone produced by the β-cells of the pancreas. Its main function is to transport glucose from the blood into the cells, where it becomes the body’s energy source.

β-cells play a key role in regulating blood sugar.
Location: in the pancreas, in the so-called islets of Langerhans.

• In type 1 diabetes: β-cells are destroyed by an autoimmune process, and the pancreas stops producing insulin.
• In type 2 diabetes: β-cells initially produce more insulin as a protective reaction, but over time they become fully exhausted.

In insulin resistance, muscle, fat, and liver cells respond inadequately to insulin. Glucose is not efficiently utilized, and the pancreas increases hormone production as compensation. As a result, hyperinsulinemia develops – an elevated level of insulin in the blood.

Why hyperinsulinemia is dangerous:

• increases triglyceride levels — fats (lipids) circulating in the blood that serve as the body’s main source of energy;
• promotes the accumulation of visceral fat;
• raises blood pressure;
• accelerates the development of atherosclerosis — a chronic condition in which cholesterol plaques form in the arterial walls, narrowing the vessels and impairing blood flow;
• increases cardiovascular risk.

Factors that trigger impaired tissue response to insulin:
• excess body weight, especially abdominal obesity
• low physical activity
• excessive intake of refined carbohydrates
• chronic stress
• sleep disorders
• genetic predisposition
• polycystic ovary syndrome
• arterial hypertension

The gradual path from insulin resistance to diabetes

• Compensation stage
  The pancreas produces more insulin, maintaining normal glucose levels.
• Prediabetes
  β-cells begin to exhaust, leading to fasting glycemia or impaired glucose tolerance.
• Type 2 Diabetes
  Compensatory mechanisms fail, resulting in persistent hyperglycemia.

Diagnostic criteria:
• fasting glucose ≥ 7.0 mmol/L
• HbA1c ≥ 6.5%

Type 1 and Type 2 Diabetes – Key Differences and Features

Type 1 diabetes is an autoimmune process in which β-cells of the pancreas are destroyed. This results in an absolute insulin deficiency, requiring lifelong insulin therapy. The disease usually develops in childhood or young adulthood and typically has a sudden and unexpected onset.

Type 2 diabetes is primarily associated with insulin resistance. In the early stages, insulin is often produced in increased amounts, but tissues lose sensitivity to it. Over time, β-cell function declines and blood glucose levels rise.

Insulin resistance is therefore considered the key mechanism in the development of type 2 diabetes.

Important signals:
• increased fatigue, low mood
• sugar cravings
• sleepiness after meals
• darkened skin in folds (acanthosis nigricans)
• difficulty losing weight

Methods for diagnosing insulin resistance in Invitro Diagnostics laboratories:

• fasting glucose
• fasting insulin
• HOMA-IR index
• glycated hemoglobin (HbA1c)
• lipid profile

If needed, an oral glucose tolerance test is performed. Details here.

! A normal glucose level does not exclude the presence of insulin resistance.

The scale of the problem: What is happening in the world

According to the International Diabetes Federation, the prevalence of diabetes worldwide continues to rise. Hundreds of millions of people live with this condition, with type 2 diabetes accounting for the vast majority of cases. Even more people are in the prediabetes stage – metabolic disturbances associated with insulin resistance. [1]

Today, diabetes prevention is considered an important public health priority in many countries.

Can the process be stopped?

Yes - especially in the early stages.
Insulin resistance is a reversible metabolic disorder.

Main directions of correction:

1. Weight loss (5–10% of body weight already improves insulin sensitivity)
2. Regular physical activity
3. Dietary adjustments to reduce refined carbohydrates
4. Sleep normalization
5. Stress management
6. Medication therapy as indicated by a physician

The earlier changes are detected, the higher the likelihood of preventing diabetes, even with a genetic predisposition.

Sometimes the most dangerous disease is the one that doesn’t hurt for a long time.

[1] https://idf.org/who-we-are/about-idf/