The small intestine absorbs three types of carbohydrate products: glucose, galactose, and fructose. Starch digestion begins in the mouth and is aided by salivary amylase. The small intestine is where the bulk of carbohydrate digestion takes place. Starches are polymers of sugars linked together. When broken down into their component sugars, starches are able to be absorbed by specific receptors on the surface of intestinal cells. These sugars are then processed by enzymes present in the liver and turned into glycogen, which is stored in the liver, or else converted directly into blood sugar - glucose.
Starch is found in plants and consists of two main components: amylose and amylopectin. Amylose is a linear molecule made up of many long chains of glucose molecules connected together. This structure makes it difficult for enzymes to break them down so they cannot be completely digested in the stomach. Amylopectin has a branched chain structure composed of several shorter chains of glucose molecules attached together. It is this property that allows the enzyme alpha-amylase to break down amylopectin more easily than other carbohydrates such as maltodextrins which contain only glucose molecules linked together. After breaking down into monomers in the digestive system, both amylose and amylopectin can be absorbed by the small intestine.
Carbohydrates are processed in three parts: the mouth, the stomach, and the small intestine. Carbohydrase enzymes convert starch to sugars. Amylase, another starch-digesting enzyme, is present in your saliva. Your stomach acids further break down proteins and carbohydrates. The pancreas produces two types of enzymes: proteases, which break down protein; amylases, which break down starch.
Starchy foods include grains such as wheat, corn, and rice as well as vegetables like potatoes and peas. Starchy fruits include bananas and apples. Avoid eating large quantities of starch at one time because it will fill your stomach and cause you to feel bloated later on. Eating more nutritious food options instead may help relieve some of those uncomfortable symptoms.
The body uses both carbohydrate digestion enzymes and acid to break down starch. Because acid is needed for other digestive processes too, having more than one way to digest starch can help prevent malnutrition due to a lack of nutrients.
Although your body can use enzymes to break down starch, it does so much better when you give it the whole grain instead of just the starchy part. Whole grains contain a variety of components, including fiber, vitamins, minerals, and antioxidants that contribute beneficial qualities for your health. A healthy diet should consist of several small meals rather than one or two large ones for best results in maintaining a healthy weight.
Glucose is the primary fuel source for your body's cells; they can't use oxygen to break down glucose so it must be ingested into the body in a digestible form. Glucose is also the main component of blood sugar. Your body uses glucose just like gasoline uses oxygen - it is its energy source. When you eat foods containing glucose, the nutrients in those foods are used by your body instead of being stored as fat.
Your body can absorb up to 1,500 milligrams of glucose per day. This amount will not cause any problems for most people. However, if you have diabetes or another condition that prevents you from processing glucose properly, more than 1,500 milligrams of this sugar per day may cause problems with your kidneys, heart, nerves, and eyes.
The majority of the glucose consumed by the average person is used as energy. The rest is processed by the liver. Any excess glucose not used by body cells is converted into glycogen storage molecules for future use. Humans store about 10 to 15 grams of glycogen. Glycogen is converted back into glucose when needed for energy.