What is Insulin? Insulin Function and Insulin Resistance Explained

What is Insulin?

If you know somebody living with diabetes, chances are you have heard of insulin.

But what is it exactly and how does it work?

Simply put, insulin is a hormone created by your body that regulates blood sugar levels. It helps move sugar, or glucose, from the blood into cells for use as energy.

Without insulin, an excess of glucose (sugar) can build up in our blood, which can lead to some serious issues.

Where is Insulin Produced?

Insulin is produced in the pancreas or more specifically the beta cells of the pancreatic islets.

When blood sugar levels start to rise these beta cells are stimulated.

As a result, they begin to produce insulin to restore blood glucose concentrations to appropriate levels.

What Does Insulin Do?

Insulin plays a central role in keeping our glucose levels within appropriate boundaries.

When our blood sugar levels rise too high, it signals liver, fat, and skeletal muscle cells to take in glucose from the blood and use it for energy.

When the body has sufficient energy, it then signals the liver to store glucose as glycogen.

That way, when blood sugar levels get low the glycogen can be converted back into glucose for use.

How Does Insulin Work?

Insulin works in two main ways to keep blood glucose levels within appropriate boundaries.

When blood sugar levels rise (e.g., after a meal), it is produced by beta cells in the pancreas and released into your blood to tell the body’s cells to open up and let glucose in.

This in turn, reduces the amount of glucose in your blood and keeps blood sugar levels within an appropriate range. From there, the cells can then convert glucose into energy.

During this time, it also signals to the liver to absorb glucose and convert it into glycogen.

This is just a bundled up and stored version of glucose. In that respect, you can think of the liver as sort of a warehouse for holding excess glucose.

The liver can store around 5% of its mass as glycogen.

When blood sugar levels drop (e.g., before or in between meals), insulin production falls as well signaling to the liver that it needs to now raise blood sugar levels.

This causes the liver to breakdown some of its glycogen storage and release glucose in your blood which raises blood sugar levels to the appropriate level.

The liver cannot directly measure blood glucose levels. Instead, it relies on insulin to tell it.

What is Insulin Resistance?

When your body is functioning properly, insulin keeps blood sugar within an acceptable range.

However, in some cases your body’s cells do not respond like they should.

Insulin resistance is one such case where your body’s cells develop a diminished sensitivity.

This means your pancreas needs to produce extra to maintain healthy blood sugar levels.

However, over time the pancreas will not be able to keep up and blood sugar levels will rise which increases your risk for developing Prediabetes and Type 2 Diabetes.

It is not quite clear what causes resistance but some risk factors include: family history, being overweight, and being inactive.

How to Reverse Insulin Resistance?

There are several ways to improve your body’s sensitivity to insulin and help reverse or slow resistance. 

Dietary changes can have a dramatic impact. Eliminating things like processed foods or sugary snacks and drinks is key.

Look to replace these with healthier options like whole grains and foods that are high in fiber as research suggests that these options can reduce your risk.

Increasing your physical activity is another great option.

All activity is good but try to aim for 30 minutes of moderate activity 5x or more per week. If you are unable to do that, start with whatever you can do and work your way up.

The important thing is to start and just continue to progress.

These changes are critical, not only for tackling resistance, but for living a healthier overall lifestyle.


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