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Understanding How Sugar is Absorbed into our Blood

Have you ever wondered, where does sugar enter the blood? If so, then rest assured that I will answer that question in this blog post and make it very clear.  The body is very complicated and I will do my best to explain the process of how sugar enters our blood. 

First we will look at different sugars and  how our body digests our food including where sugar enters the blood.  Then we will take a look into where sugar is stored when not in use.  As well as how the body maintains the perfect ratio of insulin and sugar. 

A ratio which is impaired for people with diabetes. However, it is important to understand how sugar enters the blood.  It is helpful to know when making food choices about what to eat.  Do you have any ideas about where sugar enters the blood? If so, then read on to see if you are correct.    

Different Types of Sugars

There are many different types of sugar molecules that make up a carbohydrate.  Some of these sugar molecules are simple and can be broken down by the body easily.  Other sugar molecules are more complex and take the body longer to break down.  

8 types of different bagels

Simple Sugars (Carbohydrates) 

There are six different types of simple sugars found in our food.  

  • Glucose 
  • Fructose 
  • Galactose 
  • Maltose
  • Sucrose 
  • Lactose

These simple sugars are broken down by our body quickly so that they can enter into the blood to be used by the cells for energy.   

A bunch of carrots together with stems attached

Complex Sugars (Carbohydrates) 

There are 3 different types of complex sugars. 

  • Glycogen 
  • Starches 
  • Fibers 

These complex sugars are a link of simple sugars, mostly glucose that are bound together.  They take the body more time to break apart.  The body has to break these molecules apart to individual glucose molecules before they can be used. This slows down how much sugar enters the blood.

 Glycogen is a string of glucose molecules that is found in the liver.  When blood sugar is low then the body can break the glucose molecules apart for the body to use.  

Plant foods such as rice, potatoes, and beans store their long chain of glucose molecules as a starch.    

Fibers are similar to starches but different.  They too store their long chain of glucose molecules in plants such as rice, potatoes, beans, fruits, and vegetables.  The difference is that the glucose chain in fibers cannot be broken down by the digestive enzymes in our body.  

They do not contribute to sugar molecules that enter our blood. Instead they either form a gel in water and get digested by bacteria, soluble fiber, or they do not get digested and leave our colon in the form of poop, insoluble fiber.   

GI track


Going back to the beginning, carbohydrates start their digestion in the mouth and finish up in the small intestine.  


When we eat carbohydrate rich food like rice and beans, digestion starts in the mouth. There are salivary enzymes in our mouth that start to break the starch from the food we ate. When it is ready it will continue on to the stomach. 


In the stomach the broken down starches are mixed with gastric juice.  Which is then churned to break the food down into smaller particles even more.   The salivary enzymes are broken down as well since they do not work in a high acid environment. 

Small Intestine 

Once this mixture reaches the small intestine, the pancreas sends pancreatic juice. This contains enzymes and sodium bicarbonate. The enzymes continue to break down starches while the sodium bicarbonate makes the mixture less acidic. 

At this time, simple sugars, such as simple sugars in a banana are able to be absorbed into the blood.  The sugars go through the intestinal wall to enter into the blood. The starches are broken down more by the digestive enzymes before they go through the intestinal wall to enter into the blood.  

Where Does Sugar Enter The Blood

Sugar enters the blood in the small intestine. Now you know if you weren’t sure at the beginning of the article. If you want to see an ilistration of how digestion work then check out this YouTube video.

liver and pancreas smiling

How is Sugar Maintained in the Body

Now that you know where sugar enters the blood.  Let’s turn our discussion to how the body maintains sugar.  A person with diabetes is always trying to maintain their blood sugar and it is not easy.  It is a very delicate process.            


In the pancreas, islet cells produce insulin. They release insulin when there is sugar in the blood.  The role of insulin is to transport sugar from the blood to the cell.   For a person with diabetes, they either do not produce enough insulin to handle all the sugar in the blood or the insulin is unable to work effectively. 

Insulin resistance is reduced sensitivity of insulin by the cells in the body.  This can occur when excess fat blocks the access insulin needs to transport sugar into the cell. 


During a period of fasting, such as at night, our body has the ability to prevent low blood sugar. The liver stores a string of glucose molecules  together known as glycogen. When the cells need more sugar, glycogen is broken down into smaller individual glucose molecules and released into the blood.   

Final Thoughts

The body has an ability to manage and maintain high and low blood sugar levels very efficiently.  An efficiency that is not present when a person has diabetes.  For this reason, a person with diabetes needs to be mindful of the food they do eat.  

When carbohydrate rich foods are eaten such as fruits or candy.  These simple sugars are digested and absorbed by the intestine to enter the blood very quickly.  The complex sugars, starches, like quinoa and lentils are digested and broken down even more in the small intestine.  

This delays the sugar from entering the blood right away.  Which is important for a person with diabetes or a caretaker to understand.  

Remember, where does sugar enter the blood:  the small intestine. If any one has any issues with their small intestines then this can impact how sugar is absorbed.  The next time you eat bread or beans monitor your blood sugar to see how it impacts you!  

1 thought on “Understanding How Sugar is Absorbed into our Blood”

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