![]() However, if you take high doses of amino acid supplements, those could theoretically interfere with absorption of other amino acids.įig. That’s not a problem if your protein is coming from food, because it naturally contains a mix of amino acids. Amino acids with structural similarities end up competing to use these transporters. There are several different types of transport systems to accommodate different types of amino acids. Once inside, the tripeptides and dipeptides are all broken down to single amino acids, which are absorbed into the bloodstream. Tripeptides, dipeptides, and single amino acids enter the enterocytes of the small intestine using active transport systems, which require ATP. The cells that line the small intestine release additional enzymes that also contribute to the enzymatic digestion of polypeptides. Trypsin activates other protein-digesting enzymes called proteases, and together, these enzymes break proteins down to tripeptides, dipeptides, and individual amino acids. The two major pancreatic enzymes that digest proteins in the small intestine are chymotrypsin and trypsin. The pancreas secretes digestive juices into the small intestine, and these contain more enzymes to further break down polypeptides. The chyme leaves the stomach and enters the small intestine, where the majority of protein digestion occurs. 3 – Protein digestion and absorption in the small intestine Food remains in the stomach longer, making you feel full longer. Eating a high-protein meal increases the amount of time required to sufficiently break down the meal in the stomach. Protein digestion in the stomach takes a longer time than carbohydrate digestion, but a shorter time than fat digestion. Proteins are large globular molecules, and their chemical breakdown requires time and mixing. Enzymatic digestion of proteins begins in the stomach with the action of the enzyme pepsin. The powerful stomach contractions churn the partially digested protein into a more uniform mixture, which is called chyme.įig. ![]() Muscular contractions, called peristalsis, also aid in digestion. The stomach releases gastric juices containing hydrochloric acid and the enzyme, pepsin, which initiate the chemical digestion of protein. ![]() As illustrated in the image below, both mechanical and chemical digestion take place in the stomach. ![]() The mashed egg pieces enter the stomach from the esophagus. The salivary glands secrete saliva to aid swallowing and the passage of the partially mashed egg through the esophagus. The teeth begin the mechanical breakdown of large egg pieces into smaller pieces that can be swallowed. Unless you are eating it raw, the first step in digesting an egg (or any other solid food) is chewing. In the image below, follow the numbers to see what happens to the protein in our egg at each site of digestion.įig. One egg, whether raw, hard-boiled, scrambled, or fried, supplies about six grams of protein. Let’s follow the path that proteins take down the gastrointestinal tract and into the circulatory system.Įggs are a good dietary source of protein and will be used as our example as we discuss the processes of digestion and absorption of protein. When you eat food, the body’s digestive system breaks down dietary protein into individual amino acids, which are absorbed and used by cells to build other proteins and a few other macromolecules, such as DNA.
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