What Is Insulin Resistance?
Insulin is a hormone produced by pancreatic b-cells and plays a key role in regulating glucose homeostasis.1 Normally, pancreatic b-cells secrete insulin in response to rising levels of blood glucose. Insulin, by predominantly acting on liver, muscle, and adipose tissues, allows the body to take up, store, and use these glucose molecules as energy. Insulin resistance is the impaired biological response to insulin on these target tissues, which subsequently affects glucose homeostasis.1–3
How Is Insulin Resistance Related to Diabetes?
Although the exact mechanisms are still being elucidated, it is well understood that insulin resistance precedes the onset of clinical hyperglycemia and can be identified in virtually all patients with type 2 diabetes mellitus (T2DM).4,5
It is thought that insulin resistance develops through complex mechanisms involving nonmodifiable (eg, genetic predisposition) and modifiable risk factors (eg, obesity, physical inactivity, unhealthy diet).6,7 It is likely that persistent hyperglycemia (high blood glucose levels) and hyperlipidemia (high blood lipid levels) cause systemic inflammation and oxidative stress that lead to various genetic and biochemical defects that ultimately result in the decreased uptake and use of glucose in response to insulin (ie, insulin resistance).8,9
To compensate for this insulin resistance, pancreatic b-cells increase insulin production to maintain a normoglycemic state.6 This results in hyperinsulinemia (elevated levels of circulating endogenous insulin), a key characteristic of insulin resistance.1 However, as insulin resistance worsens over time and chronic hyperglycemia, hyperlipidemia, and hyperinsulinemia persist, b-cells undergo stress and damage, eventually leading to the disruption of proper insulin secretion.6 The resulted insulin resistance and impaired insulin secretion are often identified as key causes of T2DM.6,7
How Do I Know if I Have Insulin Resistance?
As insulin resistance is known to be related to T2DM, hypertension, dyslipidemia, cardiovascular diseases, and other comorbidities, early identification can significantly delay or prevent complications.10 Although testing for insulin resistance through the glucose clamp technique provides the most accurate result, routine use of the test is clinically impractical due to its laborious process and cost. Instead, regular screening of blood glucose levels, blood pressure, and blood lipid levels in individuals at high risk may be key to recognizing insulin resistance early on in its progression.11
How Do I Combat Insulin Resistance?
The best way to combat insulin resistance is through prevention.10,12 Making comprehensive and intensive lifestyle changes that involve physical activity, a healthy diet, and healthy weight loss has shown to be effective in preventing and delaying the onset of T2DM in high-risk individuals.13–15