Insulin resistance is a condition where body cells don’t respond properly to the hormone insulin. This condition leads to excessive sugar in the blood.
While sugar might seem like a benign substance, having too much of it in your blood can actually have dire consequences. It has been linked to a host of health issues, including diabetes, cardiovascular disease, hypertension, and even Alzheimer’s disease.¹ ²
The thing about insulin resistance is that it can often creep up on people. In the early stages, you might not feel unwell or have any specific symptoms. The only way to check if you have this condition is with a blood sugar test.³
Unfortunately, its low detectability means that millions around the world go about their day without realizing that they have a condition that might lead to life-threatening diseases.
It’s estimated that 15.5% to 46.5% of adults worldwide have insulin resistance, and rates vary across countries. Experts estimate that the prevalence is lowest among European nations (15.5%), while Lebanon has recorded one of the highest rates at 44.6% among a sample of 308 adults.
Other reports indicate prevalence rates of 23.3%, 39.1%, and 46.5% from Thailand, Texas (US), and Venezuela, respectively.⁴ One cross-sectional survey found that 40% of young adults (18 to 44 years) in the US have insulin resistance, and higher rates of hypertension and obesity were also observed in this group.⁵ ⁶
According to some experts, insulin resistance has become an epidemic that many of us aren’t even aware of. ⁷
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Whenever our body receives glucose and other sugars from the food we eat, it ends up in our bloodstream to be used by our cells for energy. If our cells don’t need the energy, it gets stored as fat.
Insulin is a hormone produced by the pancreas, which facilitates the process of moving sugar to our body cells. It essentially acts as a key to unlock cells for glucose absorption.
The pancreas is a very important organ that continuously monitors blood sugar levels and adjusts the amount of insulin to keep it balanced. When you eat a meal with carbohydrates, this will signal the pancreas to make more insulin. During this time, the higher insulin levels also cause fat cells to turn glucose into fats.
Conversely, insulin levels decrease when we are between meals, and our body gets its energy from breaking down fat cells. This may also signal the liver to produce glucose if there is not enough from food sources.⁸ ⁹ ¹⁰ ¹¹
When our body becomes insulin resistant, it no longer responds to the insulin hormone correctly. Cells in our muscles, fats, and liver start to ignore the signal from insulin to absorb the glucose in the bloodstream.
This causes a build-up of sugar in the blood. In response, the pancreas will initially ramp up insulin production to bring sugar levels back to normal. However, the pancreas’ ability to keep up with the insulin demand will eventually start to wane as cells become increasingly resistant.
This is when blood sugar levels start to remain consistently high, which leads to a multitude of health problems — most notably, diabetes.¹² ¹³
Insulin resistance is a major feature of type 2 diabetes, which is associated with many health complications.
Diabetes is the number one cause of blindness globally, affecting adults aged 20–74 years old. It occurs as high blood sugar damages the blood vessels in the eye. It currently affects around 7.7 million Americans, and this figure is expected to double by 2030.¹⁴ ¹⁵
Similarly, the delicate blood vessels in the kidney can get damaged and clogged by sugars present in the blood. This can ultimately lead to kidney failure, for which there is, unfortunately, no cure. Treatments usually include medication to reduce the damage done or dialysis, where blood has to be artificially cleaned by a machine. About 20% to 30% of people with diabetes will end up with kidney disease.¹⁶
Note that in contrast to type 2 diabetes, type 1 diabetes is largely influenced by genetics and generally shows up earlier in life. Type 1 diabetes is a result of an autoimmune response from the body that causes damage to the pancreas cells. However, it shares the same health complications as type 2 diabetes.
Unfortunately, insulin resistance is part of a cluster of diseases and conditions that usually occur together. Experts refer to this as insulin resistance syndrome or metabolic syndrome. In addition to diabetes, the other health issues in this group include:¹⁷ ¹ ¹⁸ ¹⁹ ²⁰ ²¹
Obesity: More than 85% of people with type 2 diabetes are overweight, and the rates of both conditions have been rising steadily over the years.
Hypertension (high blood pressure): The biological mechanisms connecting hypertension with insulin resistance are less straightforward. It is likely due to a mixture of processes like thickening of blood vessels, inflammation, and oxidative stress. What is clear is that the two conditions often occur together, with 2 in 3 people with diabetes also having hypertension.
High cholesterol: Studies have found that insulin resistance is linked to decreased high-density lipoprotein (HDL) levels (also called “good” cholesterol) and increased low-density lipoprotein (LDL) levels (also called “bad” cholesterol), which are major risk factors for heart disease.²² ²³ ²⁴
Taken together, this syndrome causes a multitude of lifestyle illnesses like cardiovascular disease, stroke, and fatty liver disease. It has also been linked to other conditions like polycystic ovary syndrome (PCOS), Alzheimer’s disease, Cushing’s disease, and mental illnesses.
Conditions like depression and anxiety occur much more frequently in people with diabetes compared to the general public. For example, some experts estimate that depression is up to three times higher in people with type 1 diabetes and twice as high in those with type 2 diabetes compared to the general global population.²⁵
It should also be noted that not all people with insulin resistance will develop these problems if it remains mild. This is why it’s important to attend regular checkups with your family doctor to understand your risks and manage them through a treatment plan to prevent further complications.
The development of insulin resistance is a complicated process with multiple causes. However, experts have identified several key factors, which include excess weight and low physical activity.²⁶
Being overweight, obese, and having excess fat around the abdomen area and organs, in particular, have been closely linked to insulin resistance. Men with a waist measurement of 40 inches or more (and 35 inches for females) are considered at higher risk.
It’s also worth noting that there are some racial differences with this risk factor. For example, Asian Americans can still be at a greater risk of insulin resistance even with a body mass index (BMI) reading that is within the normal range.
How exactly obesity leads to insulin resistance is a complicated process. Experts suggest that higher amounts of abdominal fat can lead to increased free fatty acids in the bloodstream and inflammatory response from the body, which reduces cell sensitivity to insulin.²⁷ ²⁸ ²⁹ ³⁰ ³¹
Related to this are issues like lack of physical activity and high-carbohydrate diets (especially those with high glycemic index) that also increase one’s risk of insulin resistance.³²
In addition to these primary causes, other factors that predispose to insulin resistance include long-term stress, high blood pressure, having a family history of diabetes, and chronic sleep issues.³³ ³⁴ ³⁵
Insulin is a “silent” condition without obvious symptoms at the early stages. In fact, the Centers for Disease Control and Prevention (CDC) states that even though 1 in 3 people (96 million) in the US have prediabetes, over 80% of them don’t know they have the condition. Prediabetes occurs when one’s blood sugar is elevated but not high enough to be considered type 2 diabetes. There is some degree of insulin resistance at this stage, and when left unmanaged, it can lead to type 2 diabetes.³⁶
When the level of insulin resistance is not very severe, you might experience subtle symptoms like weight gain, brain fog, increased appetite, and sometimes darkening of the skin around the armpits and neck.⁸ ³⁷
If insulin resistance becomes more severe and blood sugar levels increase in the body, classic diabetes symptoms like increased thirst, frequent urination, blurred vision, slow healing of cuts, and leg cramps will start to surface.³⁸
As it is hard to detect insulin resistance simply by observing physical symptoms, health bodies often recommend that people get their blood sugar levels tested regularly by a doctor, particularly those aged 45 years and over. Here’s a closer look at what these tests entail.
There are three common tests that measure the amount of glucose in the blood. Higher amounts of glucose indicate insulin resistance. These tests include:³⁹ ⁴⁰
HbA1C (A1C or glycosylated hemoglobin test): This test measures average blood sugar (glycosylated hemoglobin [A1C])levels over the past 2 to 3 months. A blood sample is usually taken from the patient’s arm, but no fasting is needed. A1C readings between 6.0% to 6.4% indicate prediabetes, while those with a measurement of 6.5% or higher will be diagnosed with diabetes.
Fasting Plasma Glucose Test: For this test, the patient will need to fast for 8 hours before drawing blood. The liquid part of your blood (plasma) is combined with other substances to measure glucose levels.
Oral Glucose Tolerance Test: The test is used to measure how well the body can process a standardized amount of glucose. Blood will be drawn before and after the patient has drunk a beverage with a specific amount of glucose. The tester will then compare the before-and-after blood results.
The one good thing about insulin resistance is that it can actually be prevented in many cases by controlling diet and lifestyle factors. Experts estimate that 50% of type 2 diabetes cases can be delayed or even prevented.⁴¹
Simple changes to daily lifestyle habits can have a big impact on insulin resistance and is a primary part of managing diabetes. These modifications include:
Eating a healthy and balanced diet. The type of food you eat can have a huge impact on your blood sugar levels and, ultimately, insulin resistance.
It’s important to ensure that your overall calorie intake is not excessive. The type of food that these calories are made up of is equally important. Foods that are highly processed, contain refined sugar, have saturated fats, and are low in fiber should be avoided as they cause fast spikes in blood sugar levels.
This includes white rice, white bread, starchy vegetables, cakes, and confectionery. A healthier diet would include more fruits and vegetables, whole grains, lean meat, and unsaturated fats.⁴²
Some low-carb diets have been shown to be effective in managing insulin resistance. However, experts emphasize that it’s important not to jump into fad diets too drastically as many don’t take into account the specific nutritional needs of those with health issues.
It’s best to consult your doctor when formulating a diet plan, as they will be able to create individualized treatment recommendations for your situation.⁴³ ⁴⁴ ⁴⁵ ⁴⁶
Having sufficient physical activity. Exercise can help with weight loss and improve insulin sensitivity. Just one exercise session of moderate-intensity can help increase glucose uptake by 40%.⁴⁷ ⁴⁸
Together, eating a balanced diet and getting enough exercise can help in maintaining a healthy weight and improve insulin resistance. Weight loss of even 5% to 7% has been shown to be effective in reducing type 2 diabetes risk by 58% for those who are at high risk of developing the condition.³⁶
The “silent epidemic” of insulin resistance is already affecting millions around the world. More people should be made aware of the risks so that this highly preventable condition can be avoided.
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