What are the three stages of protein digestion?

The three stages of protein digestion primarily occur in the gastric, pancreatic, and intestinal phases. Initially, in the gastric stage, the process begins in the stomach where the enzyme pepsin, activated by stomach acid, starts breaking down protein molecules into smaller chains called peptides.

Following this, during the pancreatic stage, the pancreas secretes proteolytic enzymes such as trypsin and chymotrypsin into the small intestine. These enzymes further digest the peptides into even smaller units called amino acids and small peptides, facilitating their absorption.

Finally, in the intestinal stage, the small intestine continues the digestion with the help of brush-border enzymes that complete the breakdown of peptides into single amino acids and dipeptides that can be absorbed through the intestinal lining into the bloodstream.

Understanding these stages is essential for grasping how proteins are efficiently broken down and absorbed in the body, highlighting the role of different organs and enzymes in the digestive process.