|  | Diet Nutrition | Nutrition

Digestive Enzymes & Food Absorption

Digestive enzymes are biological compounds produced by the organs of the digestive tract and used by the body to catalyze the breakdown of ingested foods into a form that can be readily utilized by cells. For the most part, digestive enzymes carry out their functions by a process known as hydrolysis. Hydrolysis refers to the breakdown of chemical bonds found in food by the addition of a water molecule. After digestion is completed, absorption takes place to transfer the products of digestion from the gastrointestinal (GI) tract to the blood stream. From there, the digested nutrients are routed to the body's organs and systems as needed.

  1. Oral Enzymes

    • Digestion begins once food enters the mouth

      The action of digestive enzymes begins from the moment food enters the digestive tract through the oral cavity, also know as the mouth. In the mouth, the salivary glands secrete salivary amylase, which begins the preliminary breakdown of the starch found in foods such as bread, pasta and potatoes.

    Gastric Enzymes

    • The acidic environment of the stomach prepares the proteins found in foods such as poultry, meat, fish and beans for digestion by denaturing and unfolding their structure. Afterward, the gastric enzyme pepsin breaks down the proteins into smaller molecules known as peptides.

    Hepatobiliary Enzymes

    • The hepatobiliary system is composed of the liver, gallbladder, and pancreas. The organs of the hepatobiliary system play an important role in the process of digestion by acting as accessory digestive organs. The liver is the site for bile production. Bile is stored in the gallbladder and is secreted into the small intestines in response to the presence of dietary fats. As an emulsifier, bile enables the fat molecules to mix with the watery environment of the small intestines. Without bile, fat molecules would float around in the intestines just like oil floats on top of water. On the other hand, the pancreas produces the enzymes trypsinogen, pancreatic amylase, and pancreatic lipase, which are responsible for continuing the digestion of proteins, carbohydrates and fats, respectively, in the small intestine.

    Intestinal Enzymes

    • The cells of the intestinal wall produce the enzymes responsible for finalizing the digestion process.

    Absorption

    • The wall of the small intestine is lined by fingerlike projections known as microvilli. The intestinal wall, which is also known as the brush border, has an extensive surface area for absorption because of those microvilli. Depending on the chemical structure of the products of digestion, they may be absorbed into the blood stream by passive diffusion, active transport or micelle formation. Once absorbed, food particles travel to the various organs and systems of the body as needed.

Nutrition - Related Articles