Insulin Resistance: Causes, Symptoms, Diagnosis, and Treatment

What is Insulin Resistance?

Insulin resistance occurs when the cells in the muscles, fat tissue, and liver do not respond properly to insulin, a hormone produced by the pancreas that helps regulate blood glucose (sugar) levels. Glucose, the body’s primary energy source, enters the bloodstream after food is digested, and insulin facilitates its entry into cells. If insulin resistance exists, the cells do not allow glucose to enter, leading to an increase in blood glucose levels. Meanwhile, the pancreas continues to produce insulin. Initially, the pancreas can produce enough insulin to maintain normal blood sugar levels, but long-term resistance can lead to persistent high glucose levels and the development of diabetes (Booth, 2024). Sometimes, insulin production can increase by up to 20 times (hyperinsulinemia) to maintain normal blood glucose levels. When the insulin-producing cells in the pancreas become exhausted, insulin secretion may stop permanently. Thus, insulin resistance can lead to the development of type 2 diabetes, which was once known as "adult-onset" diabetes because it primarily affected the elderly population (Konstantinović Birovljev, 2016).

Causes of Insulin Resistance

Anyone can develop insulin resistance, but certain factors increase the risk, such as:

• Excess body weight, especially around the abdomen, and either excess body fat or a lack of it;
• Unhealthy lifestyle, including sedentary behavior, poor diet rich in refined carbohydrates, and smoking;
• Genetic predisposition, such as having a family history of type 2 diabetes or having a mother who had gestational diabetes during pregnancy;
• Age over 45 years;
• Use of certain medications, such as steroids, antipsychotics, or HIV drugs (Mayo Clinic, 2022; D'Arrigo, 2024; Booth, 2024).

Additionally, various medical conditions are linked to insulin resistance, such as obstructive sleep apnea, fatty liver disease, polycystic ovary syndrome (PCOS), Cushing’s syndrome, lipodystrophy (which causes abnormal fat loss), low levels of "good" HDL cholesterol, high levels of triglycerides, heart disease, previous strokes, and diseases affecting blood vessels in the neck or legs (D'Arrigo, 2024).

Symptoms of Insulin Resistance

Insulin resistance can go unnoticed for years (Roland, 2024). People with insulin resistance typically do not experience any symptoms, and the condition is often discovered accidentally during routine health checks or blood tests (Mayo Clinic, 2022). Some of insulin resistance symptoms include:

• Extreme thirst or hunger;
• Hunger after eating;
• Abdominal obesity (waist circumference greater than 40 inches in men and 35 inches in women);
• Increased or frequent urination;
• Tingling in the hands or feet;
• Unusual tiredness;
• Frequent infections;
• High blood glucose levels in laboratory tests, fasting over 100 milligrams per deciliter (mg/dL);
• High triglyceride levels in fasting (150 mg/dl);
• HDL cholesterol levels lower than 40 mg/dL in men and 50 mg/dL in women;
• Blood pressure of 130/80 or higher (Roland, 2024; Booth, 2024).

Some people with insulin resistance may also develop a skin condition called acanthosis nigricans. This appears as dark, velvety patches, usually on the back of the neck, in the groin, and under the arms. While there is no cure for this condition, if it is caused by insulin resistance, treatment may help restore the normal skin color (Roland, 2024). Additionally, insulin resistance can lead to damage to small blood vessels at the back of the eyes, resulting in retinopathy. If left untreated, it can lead to the development of type 2 diabetes (Booth, 2024).

Diagnosis of Insulin Resistance

There is no single test for insulin resistance, so doctors rely on various tests to diagnose it, such as:

• Fasting glucose test (measuring blood sugar levels after fasting for at least 8 hours);
• Oral glucose tolerance test (after a fasting glucose test, a sugar solution is consumed, and a blood test is repeated two hours later);
• Hemoglobin A1c test (measures the average blood sugar level over the past 2 to 3 months and is primarily used to diagnose prediabetes or diabetes. Multiple tests may be needed to confirm results);
• Lipid panel (lipids are fatty substances in the blood, such as "bad" LDL and "good" HDL cholesterol, and triglycerides. A blood test can check your levels. High triglycerides and low "good" cholesterol are linked to insulin resistance and type 2 diabetes) (Booth, 2024).

Treatment of Insulin Resistance

The goal of treating insulin resistance is to lower blood sugar levels and prevent type 2 diabetes (Booth, 2024). Reversing insulin resistance and preventing type 2 diabetes is possible through lifestyle changes, medication, or sometimes both. The best approach will be determined by your doctor (Mayo Clinic, 2022). Although insulin resistance is not fully understood, blood sugar levels can be managed. Some lifestyle changes that may be beneficial include:

• Exercise, as it improves how the body uses insulin. It is recommended to engage in at least 30 minutes of moderate physical activity 5 days a week.
• Losing 5% to 7% of body weight in cases of overweight, as it can significantly reduce the risk of type 2 diabetes.
• Reducing the intake of processed foods and refined carbohydrates that stimulate insulin production.
• Stress management, as reducing stress can help control blood sugar levels;
• Ensuring adequate sleep, as sleeping less than 7 hours can increase insulin resistance.
• Quitting smoking, as it worsens the condition (Booth, 2024).

Conclusion

Insulin resistance is a serious health issue that can lead to the development of type 2 diabetes and other related complications if not recognized and treated in time. Although many people do not notice any symptoms of insulin resistance, early detection is possible through blood tests and monitoring risk factors. If detected and treated early, insulin resistance can be controlled, and the development of type 2 diabetes can be prevented. Regular medical checkups and lifestyle changes such as proper diet, weight control, and stress management are key to managing this condition.

*This text is intended for informational purposes only. If you experience any symptoms, it is recommended that you seek advice from your doctor or a qualified healthcare professional.

Referece

• Konstantinović Birovljev, B. (2016). Šta je to insulinska rezistencija? Kako se rešiti IR? ZZZZ SBG. Preuzeto sa https://zzzzsbg.rs/rs/sta-je-to-insulinska-rezistencija-kako-se-resiti-ir/
• Anirudh. (2021, November 30). A bunch of red bubbles floating in the air [Photograph]. Unsplash. https://unsplash.com/photos/a-bunch-of-red-bubbles-floating-in-the-air-UiwUtEqROEs
• Mayo Clinic. (2022, August 18). What is insulin resistance? A Mayo Clinic expert explains. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/obesity/multimedia/vid-20536756
• D'Arrigo, T. (2024, March 15). A visual guide to insulin resistance. WebMD. Medically reviewed by Zilpah Sheikh, MD. https://www.webmd.com/diabetes/ss/slideshow-ir-syndrome
• Booth, S. (2024, April 22). Insulin Resistance – What You Need to Know. WebMD. Medically reviewed by Jabeen Begum, MD. https://www.webmd.com/diabetes/insulin-resistance-syndrome
• Roland, J. (2024, June 10). Insulin resistance: Symptoms. Healthline. Medically reviewed by Marina Basina, MD. https://www.healthline.com/health/diabetes/insulin-resistance-symptoms