What Is Insulin Hormone and Its Functions? Key Hormone in the Spotlight

Heather Campbell
 min read

What is insulin hormone? What does it do, and why do we need it in our bodies?

What Is Insulin Hormone and Its Functions? Key Hormone in the SpotlightAnd what is the connection with the treatment of diabetes?

As a whole, insulin is the traffic controller, the floor manager, the conductor of the orchestra, the most crucial hormone of our body. It’s the only one that lowers our sugar levels. Insulin also regulates fats, amino acids (from proteins), and many other processes.

Continue reading to understand all about insulin, including a detailed description in layman’s terms of how this essential hormone functions in the human body.

What is insulin hormone: Introduction

1869 is a milestone in the history of diabetes. This is because a German medical student, Paul Langerhans, discovered cell groups in the pancreas that produced an unknown hormone until then.

These cell groups have become famous and named after their discoverer: the islets of Langerhans.

In 1921, Scottish scientist Sir Edward Schafer discovered that this hormone is essential in blood sugar regulation. This newly discovered hormone is insulin.

Physician and scientists Paul Best and Frederick Banting succeed in using insulin from a calf’s pancreas to treat a young 14-year-old diabetic.

Before 1921, patients were treated with dietary therapy, such as avoiding carbohydrates. After 1921, the glorious era of medication started.

Related: What Are the Building Blocks of a Healthy Diet? Macronutrients List

So the focus shifts from nutrition as medicine to the quick fix.

In 1965, scientists Rosalyn Yalow and Salomon Bersen discovered a technology to measure hormone levels in the blood.

From that time on, we have learned more and more about insulin. Insulin is the traffic controller, the floor manager, the conductor of the orchestra, the most crucial hormone of our body.

Hormones as messengers in our bodies

Hormones are the messengers of our bodies.

They travel through the blood throughout the body to provide all organs with a message or command about what to do or not to do.

For example, some messengers urge our kidneys to retain water (antidiuretic hormone), while others regulate our blood pressure and heart rate.

Insulin is the most important hormone in our body

However, in the interplay of hormones, there is 1 hormone that we can safely give the leading role: the hormone insulin.

Insulin is a kind of floor manager that regulates everything and, among other things, lowers our sugar levels.

Just smelling delicious smells from the kitchen releases insulin without us even having taken a bite. So basically waiting for a meal with sugars or starches (carbohydrates).

But the real spike in insulin comes when our full stomach is stimulated by the food in it and when our blood sugar levels start to rise.

Insulin is released by the beta cells of the islets of Langerhans in our pancreas.

Insulin and glucagon are like water and fire

Our pancreas also contains alpha cells, which make the counterpart of insulin, glucagon.

Glucagon and insulin are the Dr. Jekyll and Mr. Hyde of blood sugar regulation.

What is meant by this is that they both have an essential and opposite role in blood sugar balance:

  • Glucagon raises our blood sugar when it is (much too) low.
  • Insulin lowers blood sugar when it is too high.

So when blood sugar levels are too low, glucagon ensures that glucose is again taken from somewhere and is available.

We have several hormones that increase our blood sugar: glucagon, cortisol, and adrenaline. And at the same time, we only have one hormone that lowers the level. This is actually unfair.

Probably this was very much needed in prehistoric times. Sugar was much more common to be recruited from our bodies to prevent blood sugar from getting too low.

This is because we were much more likely to chase prey or, indeed, to have to run away from some predator who saw us as a delicious lunch.

There were also periods when there was no food, then glucagon provided energy from within.

Glucagon stimulates glucose production through so-called gluconeogenesis: the production of new glucose, for example, from protein.

Glucagon, cortisol, and adrenaline allowed us to quickly get sugar during the prehistoric era. By the way, we still have those hormones, so there is no need for those sugary energy drinks.

What does insulin do?

Energy is needed for our heart to pump, our brain to think, our lungs to breathe, etc.

Insulin is the doorman with the key that fits the cell lock. It opens up the cell and ensures that glucose is rushed into the body cell so that all the factories inside can keep running wonderfully and get enough fuel.

Glucose is used as a fuel or as a storage substance in the cell. If more than enough glucose is available for fuel, the rest is stored in the form of glycogen or fat.

Relationship between insulin and blood sugar control

Most people know that there is a link between blood sugar control and insulin.

Indeed, high glucose levels in the blood stimulate the pancreas to release more insulin.

Insulin then helps cells take up glucose from the blood (lowering blood sugar).

Other functions of insulin

Insulin, however, is not just about managing blood sugar. Insulin also regulates fats, amino acids (from proteins), and many other processes.

Insulin, in fact, is also a so-called anabolic hormone. This means that insulin is a building hormone. In other words, everything insulin does has to do with building and growing.

So actually, the glucose level reduction is only a tiny part of what insulin does.

What insulin still does:

  • Insulin inhibits the action of glucagon.
  • Insulin causes glucose to be converted into glycogen (in the liver and muscles).
  • Insulin stimulates growth in other parts of the body. Stem warts, a type of wart near the armpit, come from too high an insulin level, and so does an enlarged prostate. Elevated insulin levels may also be related to the growth of cancerous tumors.
  • Insulin inhibits blood sugar production (gluconeogenesis) in the liver.
  • Insulin stimulates the production of muscle tissue. Insulin supports the absorption of amino acids into the cells: the amino acids can be used to build proteins, essential for muscle building.
  • Insulin lowers blood sugar levels.
  • Insulin causes glucose to be converted into fat. So, in other words, insulin stimulates fat production.

Insulin ensures the conversion of glucose to glycogen

We usually have glucose left over after a meal, and this is handy because, after all, you never know when you’ll need it.

The liver and muscles can convert and store glucose in the form of glycogen.

In other words, glucose thus becomes glycogen when in excess, and glycogen becomes glucose again when in short supply.

So when the glucose supply is depleted, the cell can quickly make glucose (energy) again from the glycogen box. Glycogen is the muscles’ energy supply for quick action, such as running up the stairs quickly or making a short sprint.

Your muscles need to have energy immediately available if required.

But your muscles can only benefit from this for a very short time because glycogen storage is low, and that supply is already depleted within a few hours.

Glucose overload is common in practice

Unfortunately, we often eat too much glucose or carbohydrates these days. As a result, there is often more than enough available for combustion.

If blood sugar levels are high due to a lot of glucose supply, then at some point, all cells have simply had enough fuel.

But suppose, as so often happens, the food keeps coming? Then insulin, the gatekeeper, again rattles the doors of the cells, but the cells are full.

The insulin returns to the liver disappointed, with the excess glucose molecules not welcome in the body. The liver is the hero because it can solve the problem. The escapism mechanism kicks in.

Thus, the excess glucose is converted to triglycerides in the liver. These triglycerides enter the bloodstream from the liver and are also re-supplied throughout the body.

This is somewhat normal, but the liver can’t keep up if it goes too far. It can eventually lead to fatty liver disease (non-alcoholic fatty liver disease or NAFLD).

This is fat accumulation in the liver. There is an NAFLD epidemic in the world, even among young people.

The body’s cells only need triglycerides when they are out of fuel. Then they can make fuel from the triglycerides as well.

The fat cells are the saviors. They can absorb and store most of the excess triglycerides from the bloodstream. Under the influence of insulin, the triglycerides are funneled into the fat cell.

Our adipose tissue is a storehouse of fuel

Only a limited amount of glucose in the form of glycogen can fit in the muscles’ pantry.

However, our adipose tissue can store an infinite amount of glucose in the form of fat.

So not only do fatty foods become fat in the body, but sugar also becomes fat.

The excess fat goes first to the traditional fat-gathering areas: the hips and buttocks in the case of ladies. When those are full, then to the organs and the abdomen.

So our adipose tissue is a kind of pantry where the excess sugars are stored away in the form of fat.

It is beneficial for harsh times when fat cells are actually fantastic.

So, where is all this excess energy supposed to go?

An extra buffer on the buttocks or hips is a great storage spot. This is often healthy adipose tissue as well.

But the problem arises when this buffer or this pantry is full. Then fat ends up in places where it doesn’t belong. This is called ectopic fat or unhealthy visceral fat if it is in the abdomen around the organs.

What is insulin hormone: Conclusion

This hormone is one of the most important hormones made by our body and controls sugar levels and regulates fats, amino acids (from proteins), and many other processes.

That is why it’s so important to take care of it.

Related: Ignoring Stress Is Bad for Our Health: Managing It Is Important

About Heather Campbell

As a nutritionist, my field of specialization is science-based nutritional advice but more importantly, it is my goal to share capturing and inspiring stories, examples and solutions which can help plus-size individuals overcome their specific difficulties. Read More