Digestion of proteins takes place in different stages. The initial phase of protein digestion and absorption occurs in the stomach and the latter takes place in the small intestine. Proteins provide the body with amino acids, which are required by the body, but unfortunately, the body is incapable of producing them on its own. The protein digestion process basically consists of the breakdown of proteins into amino acids. There are distinctive kinds of enzymes that aid in the digestion and absorption of proteins. The enzyme called pepsin does its work in the stomach and it works best when the stomach is acidic. It breaks down the large protein molecules into smaller ones. It is here where the proteins get partly digested in the body. In the small intestine, there are other enzymes that take over the process of protein digestion in the body. These enzymes aid in protein absorption, by breaking the small protein molecules into amino acids. Protein absorption rate is faster for animal origin foods, rather than vegetarian plant origin foods, perhaps because vegetable proteins usually contain cellulose covering. Read further to explore information about protein absorption rate.
Since proteins are used by the body for repairing and building cells, understanding how protein digestion and absorption works is crucial. Proteins are also used for creating enzymes and neurotransmitters, as well as making fresh DNA and RNA. Thus, the significance of these indispensable macronutrients cannot be challenged. Protein digestion takes place in two different places in the body—the stomach and the small intestine. Both of these stages of digestion are based on certain enzymes; proteinases and proteases.
Protein digestion begins in the stomach and is catalyzed with the action of hydrochloric acid that is produced by an enzyme called ‘pepsin’. There are several factors that decide the concentration of the enzymes to break down the food such as the temperature of the food, its acidity, the time taken to consume the food and the presence of any digestive inhibitors. Cooking the food and chewing it thoroughly in the mouth helps, but the protein ingestion does not begin in the mouth.
The hydrochloric acid in the stomach is required to break down the protein to protein bonds and amino acids before it is finally absorbed by the blood. Once the protein has been partly digested by the stomach, the process continues in the upper section of the small intestine, with the help of pancreatic enzymes known as ‘trypsin’. The end amino acids are finally absorbed by the capillaries in the system, carried through the liver and circulated around the body in the bloodstream.
Consequences Of Improper Protein Digestion
The body wants amino acids and not whole proteins, which are viewed by the body as negative. These then, become what we call, ‘foreign proteins’. The body could experience strong digestive repercussions or protein backfires in the forms of allergies, nausea, vomiting, general stomach upsets and in some severe cases, even death. Some foods, which are considered too large to be digested by the small intestine, end up being passed to the large intestine as undigested or partly-digested and will likely be attacked by numerous microorganisms, which will decompose the food and result in a chemical attack, which often results in diarrhea.
Waste Products Of Protein Metabolism
The destruction of proteins in the body gives rise to two classes of waste products, nitrogenous and non-nitrogenous. The nitrogenous waste products are usually in the form of uric acid and hippuric acid, which is excreted by the kidney. The non-nitrogenous types of waste products are often excreted from the body in the form of carbondioxide and water.
Enzymes Required For Digestion & Absorption
Trypsin is a pancreatic protease enzyme, which is secreted by the pancreas and is involved in protein and fat digestion. From the stomach, protein digestion carries on in the duodenum, which represents the first segment of the small intestine. Apart from trypsin, chymotrypsin and pepsin help in the disintegration of amino acids through a chemical process in the body called as ‘hydrolysis’. Pepsin is regarded as one of the most important enzymes in the process of digestion and absorption. The gastric enzyme represents the single protease capable of digesting collagen, a fibrous protein that is one of the main constituents of connective tissue in animals.
The protein in the body disintegrates continuously and as a result, our bodies need to replace these lost proteins immediately. The stomach and the small intestine play a vital role in the break-down and digestion of the food we consume and is finally, absorbed by the capillaries. Hope the article has familiarized you with protein digestion and absorption process.