Sugars are digested and absorbed to provide your body with its greatest source of energy. During digestion, complex sugars are broken down into monosaccharides and absorbed into the bloodstream. Monosaccharides, the simplest sugars, include glucose, galactose and fructose. Digestion occurs in the mouth, stomach and intestine.

In the Mouth and Stomach

Sugar digestion begins in your mouth. An enzyme called salivary amylase breaks down the sugar into smaller particles. Salivary amylase only affects a small amount of sugar due to the limited amount of time the sugar spends in your mouth. Once in the stomach, salivary amylase becomes inactive due to stomach acid, or hydrochloric acid. The stomach acid continues to break apart the sugar molecules into smaller pieces. Similar to the mouth, the stomach empties the sugar into your intestines before it has a sufficient amount of time to fully break the sugar into monosaccharides.

In the Intestine

The majority of sugar digestion occurs in the intestine. Various enzymes are specific to certain sugars. For instance, the enzyme lactase breaks down lactose into the monosaccharides glucose and galactose. Other enzymes include maltase, sucrase and isomaltase, which digest maltose, sucrose and isomaltose, respectively. The enzymes break down the sugars into monosaccharides, which are absorbed into the blood and used for energy.

Indigestible Sugars

Indigestible carbohydrates cannot be broken down by the human body. They include various fibers, such as cellulose, hemicellulose, pectin and gum. Fiber passes through your mouth, stomach and small intestine without changing significantly. In the large intestine, bacteria ferments certain fibers known as prebiotics. The fermentation process chemically breaks down the prebiotics, creating short-chain fatty acids that provide energy to the cells in your colon. Prebiotics aid in gut health by helping your good bacteria flourish and grow. Common prebiotics include chicory root and inulin.

Choosing Healthy Sugars