What is Glycogen? Let's talk about our body's energy storage in simple terms!

Have you ever wondered how our bodies store the energy we get from the food we eat for later use? That's where a special substance called glycogen comes in. It's like a power bank that keeps our phones charged.

What is glycogen?

Simply put, glycogen is a type of sugar called glucose that is stored in our bodies. It is made up of many glucose molecules bonded together.

Now you may be asking what glucose is. Glucose is the main fuel that provides energy to our bodies. We get this glucose from some of the foods we eat, especially those that contain carbohydrates. If the glucose from the foods we eat is not immediately needed for energy, our bodies store it as glycogen in the liver and muscles , for later use.

The process by which our body makes glycogen from glucose is called Glycogenesis . Also, the process by which this glycogen is converted back into glucose when needed and used for energy is called Glycogenolysis . Both of these processes are aided by different types of enzymes . Enzymes are special types of proteins found inside our cells. They act as catalysts and help various processes in the body to run smoothly. There are thousands of such enzymes throughout our body, and each of them performs an important function.

What is the difference between Glycogen, Glucose and Glucagon?

Now let's see what the difference is between these three words: Glycogen, Glucose, and Glucagon. All three are related to the way our bodies use carbohydrates for energy, but each of them has a different function.

GlucoseIt is the type of sugar that we get from the foods we eat, especially carbohydrates. The main type of sugar in our blood is blood glucose, or what we call 'blood sugar '. This sugar gives our body energy, and it also nourishes our organs, muscles, and nervous system. Glucose is very important because it is the main source of energy for our brain. In fact, our brain constantly needs glucose, which is why it is recommended that an adult consume at least 130 grams of carbohydrates per day.

We now know that when our body suddenly no longer needs glucose, it is stored in our liver and muscles as glycogen .

Glucagon is a hormone produced by our pancreas. It helps convert stored glycogen back into glucose and release it into the blood. The body can then use that glucose for energy. Glucagon and insulin are the two hormones that mainly control blood glucose levels in our body.

Is glycogen a carbohydrate?

So, is glycogen a carbohydrate? Well, glycogen is made from carbohydrates, that is, from the starchy foods we eat. However, glycogen is not a carbohydrate per se. When we eat foods that contain carbohydrates, our bodies break them down and turn them into glucose to use for energy. Glycogen is the way that glucose is stored. It is made up of a bunch of glucose molecules linked together.

Where is glycogen stored?

Okay, so where is this glycogen stored in our body? Glycogen is mainly stored in ourIt is found in the liver and skeletal muscles . Muscles are the muscles that are attached to our bones and tendons. In addition, a very small amount is also stored in our brain.

Although our liver stores a higher percentage of glycogen than our muscles, our total muscle mass is much larger than our liver, so only three-quarters of the total glycogen in the body is in our muscles.

When we exercise vigorously, especially for a long time, the amount of glycogen in active muscle cells can decrease significantly. The amount of glycogen in liver cells changes throughout the day. This is due to several factors:

• The amount of carbohydrates we eat.
• The time gap we keep between meals.
• The intensity and duration of the physical activity we have done recently.

Imagine, if you don't eat for 12 to 24 hours (fasting), almost all of the glycogen in the liver is used up.

What service does glycogen provide to our body?

Now let's see what service this glycogen provides to our body. Depending on where it is stored – whether in the liver or in the muscles – its function also varies slightly.

Function of Liver Glycogen Stores

Our bodies use glycogen, mainly in the liver , to help control our blood glucose levels.

Normally, our bodies carefully control our blood sugar levels with hormones called glucagon and insulin. If our blood sugar levels get too low, which is called hypoglycemia , our pancreas releases more glucagon. One of the things glucagon does is convert glycogen in the liver back into glucose and release it into the blood. You may recall that we called this process glycogenolysis. When glucose is released into the blood, cells throughout the body can use it for energy.

Glycogen stores in the liver also help with muscle function and exercise to some extent. As soon as you start exercising, your working muscles use glucose for energy, so the liver starts breaking down glycogen to maintain blood sugar levels. However, your muscles primarily use their own glycogen stores.

Function of Muscle Glycogen Stores

Glycogen in muscles primarily acts as a source of metabolic fuel for our muscles.

For us to move, our muscles need a lot of energy. Imagine, if our muscles were to take glucose from the blood to get this energy, the glucose in the body would run out very quickly.

That's why our bodies store three-quarters of all glycogen in each skeletal muscle. This allows the muscles to continue to receive energy without significantly affecting blood sugar levels, especially during exercise.

The rate at which glycogen in our muscles is depleted is largely related to the intensity of physical activity. As the intensity of exercise increases, the rate at which glycogen in the muscles is depleted also increases. Therefore, during high-intensity activities, such as sprinting , the glycogen stores in active muscle cells can be depleted very quickly, even if the total duration of the activity is relatively short.

When we eat enough carbohydrates, our muscles fill up with glycogen again.

What is Glycogen Storage Disease (GSD)?

Sometimes, problems can arise with this glycogen. One such condition is glycogen storage disease, or GSD for short.

GSD is a rare, inherited condition.This is when a person is born without certain enzymes that are needed to make and/or break down glycogen. Because our bodies use many different enzymes to process glycogen, there are many different types of GSD. GSD can often cause liver damage and muscle weakness . In many types of GSD, symptoms first appear in infancy or early childhood.

What tests are available to check glycogen levels?

So, are there any special tests to check the glycogen levels in our body? Actually, there is no special test that only measures glycogen levels. Moreover, our glycogen levels constantly change depending on the amount of work we do and the amount of carbohydrates we eat per day.

Instead, if you have symptoms, doctors use other tests to see if you have a problem with the way your body makes and breaks down glycogen, called glycogen storage disease (GSD). These tests are:

• Blood tests: Things like a liver function panel and kidney function panel can help you see how well these organs are working. A blood glucose level test can help you see how well your body is using glycogen. People with GSD often have low blood sugar.
• Abdominal ultrasound: This imaging test can help your doctor see if your liver is enlarged.
• Tissue biopsy: Your doctor may take a small tissue sample from your muscle or liver and measure the levels of glycogen or enzymes in it.
• Genetic testing: Your doctor may also recommend genetic testing to see if you have the gene for Glycogen Storage Disease.

What is the most important thing we need to remember from this article?

Okay, so now you probably understand that glycogen is essential for controlling our blood sugar levels and providing energy for exercise. Fortunately, problems with the production and use of glycogen in our bodies are very rare.

The best thing you can do for your glycogen levels, especially if you're an athlete, is to eat enough carbohydrates every day. If you have any questions about your diet and exercise goals, be sure to talk to your doctor or a registered dietitian. They can give you advice that's right for you.