Insulin resistance, also known as insulin insensitivity or impaired insulin sensitivity, is a metabolic disorder characterized by decreased responsiveness of body's cells to insulin. Insulin is an energy storage peptide hormone which facilitates the uptake of glucose from the bloodstream into cells.
How Insulin Works
After a meal, macronutrients are broken down into simple biomolecules such as amino acids, glucose, and fats, which are then released into the bloodstream for energy use or storage. This increase glucose delivery is sensed by the pancreas which releases insulin to maintain normal blood glucose levels. Insulin facilitates glucose transport into muscle, liver, and adipose cells (where it is converted to fats), while also inhibiting gluconeogenesis, the liver's glucose production process. Once glucose makes its way into cells with the help of insulin, it can either be oxidized in the mitochondria to release energy or polymerized as glycogen for energy storage.
A look at Insulin Resistance
In insulin resistance, cells fail to take in glucose despite the presence of insulin, creating an increase in blood glucose (hyperglycemia) and prompting the pancreas to release more insulin to restore homeostasis. This leads to hyperinsulinemia, a condition where elevated insulin levels are required to stimulate glucose uptake. This elevated insulin response at early stages of insulin resistance can normalize blood glucose levels, making insulin resistance hard to detect through glucose monitoring alone. As insulin resistance persists and become chronic, pancreatic exhaustion can occur leading to persistent hyperglycaemia and impaired glucose regulation.
As of date, insulin resistance affects approximately 40% of the global population, posing a significant health concern. This condition increases the risk of developing type 2 diabetes, cardiovascular disease, PCOS (Polycystic ovary syndrome), cancer, Alzheimer disease and other metabolic disorders.
Some Contributing Factors and Prevention Strategies
While there’s a genetic component to insulin resistance, lifestyle factors such as diet, physical inactivity, stress and sleep deprivation have been shown to be key players as well.
Diet: A diet high in processed foods, refined carbohydrates, and sugars accelerates glucose delivery into the bloodstream causing a significant spike in blood glucose and insulin response. Another component of sugar, fructose, cannot be taken up by cells and is shuffled to the liver, where it is converted to fats. This result in a condition called non-alcoholic fatty liver disease (NAFLD). Having a whole food diet with healthy fats and lean protein has been shown to reduce the glycemic load in the blood resulting in a steady-state release of insulin. The fiber content in whole foods also increases satiety reducing the stimulus to eat more food.
Exercise: Physical inactivity decreases glucose uptake in muscles. Incorporating a regular physical activity such as walking, cycling, and weightlifting, helps increase insulin sensitivity in muscle cells, which then lowers the glucose load in the bloodstream.
Chronic Stress: Stress stimulates the sympathetic nervous system which increases epinephrine and cortisol levels. These hormones increase glucose levels and insulin response in the body which can lead to insulin resistance. Breathing techniques, such as diaphragmatic breathing and box breathing, have been shown to help manage stress. Yoga and meditation are also great tools to help induce a calmer state of the mind and body.
Sleep: Sleep deprivation causes a stress response as describe above and also increases ghrelin, a hormone responsible for hunger. This results in excessive eating and elevated glucose levels in the bloodstream, which cascades to high insulin levels and metabolic disease. For adults, the recommended amount of sleep is 7-9 hours. Establishing a consistent sleep schedule with reduced exposure to blue light before bed, limiting food consumption two hours before bed, and having sunlight exposure soon after waking up can help regulate the circadian rhythm and improve sleep quality.
By adopting a balanced lifestyle, including a whole food diet, regular physical activity, stress management, and quality sleep, individuals can reduce their risk of developing insulin resistance and its associated complications, ultimately maintaining optimal metabolic health.
Sources
https://onlinelibrary.wiley.com/doi/10.1002/dmrr.3667 Assessed and Endorsed by the MedReport Medical Review Board