INSULIN RESISTANCE

Since lot of discussions are going on in our forum I thought a topic on Insulin Resistance will be appropriate at this juncture

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JAGANNATHAN

 

Insulin resistance, also known as impaired insulin sensitivity, happens when cells in the  muscles, fat and liver don’t respond as they should to insulin,. Insulin resistance can be temporary or chronic and is treatable in some cases.

Under normal circumstances, insulin functions in the following steps:

• Our body breaks down the food we eat into glucose  which is our body’s main source of energy.
• Glucose enters our bloodstream, which signals our pancreas to release insulin.
• Insulin helps glucose in our blood to be metabolised and to enter our muscle, fat and liver cells so they can use it for energy or store it for later use.
• When glucose enters our cells and the levels in our bloodstream decrease, it signals our pancreas to stop producing insulin.

For several reasons, our muscle, fat and liver cells can respond inappropriately to insulin, which means they can’t efficiently take up glucose from our blood or store it. This is insulin resistance. As a result, our pancreas makes more insulin to try to overcome our increasing blood glucose levels. This is called hyperinsulinemia.

As long as our pancreas can make enough insulin to overcome our cells’ weak response to insulin, our blood sugar levels will stay in a healthy range. If our cells become too resistant to insulin, it leads to elevated blood glucose levels (hyperglycemia), which, over time, leads to prediabetes and Type 2 diabetes.

In addition to Type 2 diabetes, insulin resistance is associated with several other conditions, including:

• Obesity.
• Cardiovascular disease.
• Nonalcoholic fatty liver disease.
• Metabolic syndrome.
• Polycystic ovary syndrome (PCOS).

INSULIN RESISTANCE AND DIABETES

Anyone can develop insulin resistance — temporarily or chronically. Over time, chronic insulin resistance can lead to prediabetes and then Type 2 diabetes if it’s not treated

Prediabetes happens when our blood glucose levels are higher than normal, but not high enough to be diagnosed as diabetes. Prediabetes usually occurs in people who already have some insulin resistance.

Prediabetes can lead to Type 2 diabetes. T2D happens when our pancreas doesn’t make enough insulin or our body doesn’t use insulin well (insulin resistance), resulting in high blood glucose levels.

We often use a blood glycated hemoglobin (A1c) assessment to diagnose diabetes. It shows our average blood sugar level for the past three months. In general:

• An A1c level below 5.7% is considered normal.
• An A1c level between 5.7% and 6.4% is considered prediabetes.
• An A1c level of 6.5% or higher on two separate tests indicates type 2 diabetes.

WHO ARE AFFECTED BY IR

Insulin resistance can affect anyone — you don’t have to have diabetes — and it can be temporary (for example, using steroid medication for a brief period causes insulin resistance) or chronic.

The two main factors that seem to contribute to insulin resistance are excess body fat, especially mid segment obesity, and a lack of physical activity.

People who have prediabetes and Type 2 diabetes usually have some level of insulin resistance. People with Type 1 diabetes can also experience insulin resistance.

CONSEQUENCES OF IR

The development of insulin resistance typically increases insulin production (hyperinsulinemia) so our body can maintain healthy blood sugar levels. Elevated levels of insulin can result in weight gain, which, in turn, makes insulin resistance worse.

Hyperinsulinemia is also associated with the following conditions:

Higher triglyceride levels.

Atherosclerosis.

 Hypertension.

Insulin resistance is also the main feature of metabolic syndrome,

Features of metabolic syndrome include with Mid segment obesity and Insulin Resistance the following also

Elevated blood glucose levels.

An elevated triglyceride level.

Low levels of high-density lipoprotein (HDL)

High blood pressure.

It is not necessary to have all four of these features to have metabolic syndrome.

Symptoms and Causes

If we have insulin resistance, and if our pancreas can increase insulin production to keep our blood sugar levels in range, we won’t have any symptoms.

However, over time, insulin resistance can get worse, and the Beta cells in our pancreas can wear out. Eventually, our pancreas is no longer able to produce enough insulin to overcome the resistance, leading to elevated blood sugar (hyperglycemia), which does cause symptoms.

Many people have no symptoms of prediabetes, often for years. Prediabetes may be invisible until it develops into Type 2 diabetes. Some people with prediabetes may experience the following symptoms:

• Acanthosis nigricans.
• Skin tags
• Diiabetes-related retinopathy.

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GENETICS

Several genes have been identified that make a person more or less likely to develop insulin resistance. In addition, older people are more prone to insulin resistance.

AQUIRED CAUSES OF IR

• Excess body fat: obesity, especially Mid segment obesity and  visceral fat, are the primary cause of insulin resistance. A waist measurement of 40 inches or more for men and 35 inches or more for women is linked to insulin resistance. Studies have shown that belly fat makes hormones and other substances that can contribute to long-term inflammation in our body. This inflammation may play a role in insulin resistance
• Physical inactivity: Physical activity makes our body more sensitive to insulin and builds muscle that can absorb blood glucose. A lack of physical activity can have opposite effects and cause insulin resistance. In addition, a lack of physical activity and a sedentary lifestyle are associated with weight gain, which can also contribute to insulin resistance.
• Diet: A diet  highly processed, high-carbohydrate foods and saturated fats has been linked to insulin resistance. Our body digests highly processed, high-carbohydrate foods very quickly, which causes our blood sugar to spike. This puts extra stress on our pancreas to produce a lot of insulin, which, over time, can lead to insulin resistance.
• Certain medications: Certain medications can cause insulin resistance, including steroids, some blood pressure medications, certain HIV treatments and some psychiatric medications.

Hormonal disorders that can cause insulin resistance

Issues with certain hormones can affect how well our body uses insulin. Hormonal disorders that can cause insulin resistance include:

• Cushing’s syndrome: This condition happens when there’s extra cortisol in our body. Cortisol, the “stress hormone,” is vital to regulating our blood sugar levels (by increasing them) and turning food into energy. Excess cortisol can counteract the effects of insulin, causing insulin resistance.
• Acromegaly: This is a rare but serious condition that happens when we have high levels of growth hormone (GH). High levels of GH can cause increased production of glucose, which can lead to insulin resistance.
• Hypothyroidism:. Thyroid plays a large role in regulating our metabolism. When it makes too little thyroid hormone, it slows down your metabolism, including your glucose metabolism, which can lead to insulin resistance.

Genetic conditions that cause insulin resistance

Certain inherited genetic conditions  can cause insulin resistance for various reasons.

Diagnosis and Tests

Insulin resistance is difficult to diagnose because there is no routine tests for it, and as long as your pancreas is producing enough insulin to overcome the resistance, you won’t have any symptoms.

As there’s no single test that can directly diagnose insulin resistance, several factors are considered when assessing insulin resistance, includingr:

• Medical history.
• Family history.
• Physical exam.
• Signs and symptoms.
• Test results.

TESTS

• Glucose: A fasting plasma glucose (FPG) or a glucose tolerance test (GTT) may be used to screen for, diagnose and/or monitor prediabetes, type 2 diabetes or gestational diabetes.
• Glycated hemoglobin A1c (A1c): This test reveals the average blood glucose levels over the past three months.
• Lipid panel: This is a group of tests that measure specific lipids in your blood, such as total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides.

Management and Treatment

Since not all factors that contribute to insulin resistance can be treated, such as genetic factors and age, lifestyle modifications are the primary treatment for insulin resistance. Lifestyle modifications include:

• Eating a healthy diet: Avoid eating excessive amounts of carbohydrates (which stimulate excess insulin production) and eating less unhealthy fat, sugar, red meats and processed starches. Instead, eat a diet of whole foods that includes more vegetables, fruits, whole grains, fish and lean poultry.
• Physical activity: Getting regular amounts of moderate-intensity physical activity helps increase glucose energy usage and improve muscle insulin sensitivity. A single session of moderate-intensity exercise can increase glucose uptake by at least 40%.
• Losing excess weight: It is recommended   to lose excess weight to treat insulin resistance. One study revealed that losing 7% of our excess weight can reduce the onset of Type 2 diabetes by 58%.

Over time, these lifestyle modifications can:

• Increase insulin sensitivity (reduce insulin resistance).
• Lower  blood glucose levels.
• Decrease blood pressure.
• Decrease triglyceride and LDL  cholesterol levels.
• Raise HDL  cholesterol levels.

Drugs used to treat insulin resistance

While there are currently no medications that treat insulin resistance specifically the following drugs may be considered

1.Blood pressure medication.

2.Metformin for diabetes.

3.Statins to lower LDL cholesterol.

Diet and insulin resistance

Diet has a big impact on our blood sugar and insulin levels.                                                        Highly processed, high-carbohydrate and high-fat foods require more insulin.

In general, eating foods that have a low to medium glycemic index and limiting foods that have a high glycemic index can help you reverse and/or manage insulin resistance.

Eating foods with fiber also helps regulate blood sugar levels because it takes our body longer to digest fiber, meaning our blood sugar levels don’t spike as much.

Risk factors for developing insulin resistance

Certain genetic and lifestyle risk factors make it more likely to develop insulin resistance or prediabetes.

 Risk factors include:

• Overweight or obesity, especially Mid segment obesity
• Being age 45 or older.
• A first-degree relative (parent or sibling) with diabetes.
• Having a sedentary lifestyle.
• Certain health conditions, such as high blood pressure and abnormal cholesterol levels.
• A history of gestational diabetes.
• A history of heart disease or stroke.
• Having a sleeping disorder, such as sleep apnea.
• Smoking.

Although we can’t change certain risk factors for insulin resistance, such as family history or age, we can try lowering our chances of developing it by maintaining a healthy weight, eating a healthy diet and exercising regularly.

Prognosis

The prognosis  of insulin resistance depends on several factors, including:

• The cause of insulin resistance.
• The severity of insulin resistance.
• How well our insulin-producing cells are functioning
• Susceptiblity  to developing complications from insulin resistance.
• Adherence to treatment and the body’s response to treatment.

People can have mild insulin resistance that never turns into prediabetes or Type 2 diabetes.

People can also have insulin resistance that’s reversible or very manageable with lifestyle changes.

 For some people who have inherited conditions that cause severe insulin resistance, it can be life-threatening or lead to death.

Thank you

Suggestions, Comments and Remarks are welcome and appreciated

JAGANNATHAN