Answer:
Carbohydrates are not efficiently digested in the stomach primarily due to the acidic and enzymatic environment of the stomach, which is optimized for the digestion of proteins.
- Acidic Environment: The stomach contains gastric juices, primarily hydrochloric acid, which creates an extremely acidic environment (pH 1-2). This acidity is essential for the activation of the enzyme pepsin, which is responsible for breaking down proteins into smaller peptides. However, this acidic environment is not conducive to the digestion of carbohydrates, which typically requires a more neutral or slightly acidic pH.
- Digestion of Carbohydrates in the Small Intestine: The primary site for carbohydrate digestion occurs in the small intestine. Here, the partially digested carbohydrates, along with other nutrients, are mixed with pancreatic juices that contain enzymes like pancreatic amylase, which is highly effective in breaking down carbohydrates into sugars. The small intestine also provides a more suitable pH environment for carbohydrate digestion.
- Role of Saliva: Carbohydrate digestion actually begins in the mouth, where salivary amylase is secreted to initiate the breakdown of starches into simpler sugars. This process is essential for the efficient digestion of carbohydrates.
Step-by-step explanation:
In summary, while some initial carbohydrate digestion does occur in the mouth and stomach, the stomach's highly acidic environment and limited carbohydrate-digesting enzymes make it a less efficient site for carbohydrate digestion compared to the small intestine. Most of the breakdown of carbohydrates into absorbable sugars takes place in the small intestine, where the conditions are more favorable for this process.