Digestion of Carbohydrate

Digestion of Carbohydrate

The main function of carbohydrates is to provide your body with energy to support muscular work, brain activity, breathing and other important activities. Carbohydrates are made up of sugars known as saccharides. Most carbohydrate foods contain many saccharides linked together, which are known as polysaccharides. Carbohydrate digestion begins in the mouth and is complete when the polysaccharides are broken down into single sugars, or monosaccharides, which can be absorbed by the body.

The three types of carbs are:

starches or complex

carbssugars or simple carbs


Both simple and complex carbohydrates break down intoglucose (aka blood sugar). A simple carb is one that’s comprised of one or two sugar molecules, while a complex carb contains three or more sugar molecules. Fiber, on the other hand, is found in healthy carbs, but isn’t digested or broken down. It’sbeen shown to be good for heart health and weight management.

Naturally-occurring simple sugars are found in fruit and dairy. There are also processed and refined simple sugars that food companies may add to foods such as sodas, candy, and desserts.

Good sources of complex carbohydrates include:
whole grains






Fiber is found in many healthy carbs such as:



whole grains



Digestion of Carbohydrate

In the Mouth

Carbohydrate digestion begins in the mouth. The salivary glands in the mouth secrete saliva, which helps to moisten the food. The food is then chewed while the salivary glands also release the enzyme salivary amylase, which begins the process of breaking down the polysaccharides in the carbohydrate food.

In the Stomach

After the carbohydrate food is chewed into smaller pieces and mixed with salivary amylase and other salivary juices, it is swallowed and passed through the esophagus. The mixture enters the stomach where it is known as chyme. There is no further digestion of chyme, as the stomach produces acid which destroys bacteria in the food and stops the action of the salivary amylase.

In the Pancreas and Small Intestine

After being in the stomach, the chyme enters the beginning portion of the small intestine, or the duodenum. In response to chyme being in the duodenum, the pancreas releases the enzyme pancreatic amylase, which breaks the polysaccharide down into a disaccharide, a chain of of only two sugars linked together. The small intestine then produces enzymes called lactase, sucrase and maltase, which break down the disaccharides into monosaccharides. The monosaccharides are single sugars that are then absorbed in the small intestine.

In the Large Intestine (Colon)

Carbohydrates that were not digested and absorbed by the small intestine reach the colon where they are partly broken down by intestinal bacteria. Fiber, which cannot be digested like other carbohydrates, is excreted with feces or partly digested by the intestinal bacteria.


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