Describe the process of carbohydrate digestion in human beings
The process of carbohydrate digestion in human beings begins in the mouth. As you chew food, your saliva starts breaking down starches into smaller molecules called maltose through the action of an enzyme called salivary amylase.
Once food is swallowed, it travels down the esophagus and reaches the stomach. However, carbohydrate digestion mostly pauses here because the stomach primarily focuses on protein digestion. However, a small amount of starch digestion may continue for a short time due to the presence of salivary amylase.
The majority of carbohydrate digestion occurs in the small intestine. When food enters the small intestine, it triggers the release of hormones such as cholecystokinin (CCK) and secretin, which stimulate the pancreas to release digestive enzymes. Pancreatic amylase is one of the enzymes secreted by the pancreas. It further breaks down the starch into smaller fragments, mainly maltose.
The small intestine also produces an enzyme called maltase, which specifically breaks down maltose into glucose molecules. The lining of the small intestine contains tiny finger-like projections called villi, which increase the surface area for absorption. Glucose molecules are absorbed into the bloodstream through the villi and transported to the liver.
Some starches, such as those found in whole grains, legumes, and certain vegetables, contain resistant starch. Resistant starch is not easily digested in the small intestine and passes into the large intestine. There, it is fermented by the gut bacteria, producing short-chain fatty acids that provide energy and promote a healthy gut environment.
Overall, the process of carbohydrate digestion involves the actions of various enzymes, such as salivary amylase, pancreatic amylase, and maltase, to break down starches into smaller sugars like glucose, which can be absorbed and used as a source of energy by the body.