Discover the Role of Enzymes In the Digestive System

As you might have guessed the role of enzymes in the digestive system is diverse and critical. The main job is to turn the food we eat into something usable for the cells of the body. While this is straightforward in theory, food is made up of complex inconsistent materials. The digestive system has to respond to these food variations  regularly and consistently. In other words, the digestive process takes the inconsistency of food particles and eating patterns and turn them into something consistent and reliable for the cells of the body. It is a coordinated well planned out action that has a lot of room for mistakes, disruptions, and problems. Lets look at the basic steps in digestion so we can better understand role of enzymes in the digestive system and better understand how and where problems arise.


Getting the Most Out of the Food We Eat

Starting from even before you open your mouth to take a bit, the body starts to prepare for the food with stomach secretions, saliva production, and increased blood flow to the digestive tract. These actions are triggered by looking at the food and the smells of the food. This preparation is important to get the most nutrients and energy out of the food you eat. Without it, its like putting food into an unheated oven. It will still cook eventually, but not as efficiently.

Once you take the first bite of food the breakdown begins in the mouth with the enzymes in your saliva and the mechanical action of chewing. This initial breakdown serves two main functions. The chewing starts the separation of larger protein bonds and the enzymes in the saliva separate the carbohydrate bonds in the food. As this occurs it changes the structure of food and increases sweetness of the food. The actual taste of the food triggers more acid secretions in the stomach.

Learn the clues to an unhealthy digestive system and the importance of digestive enzymes as explained in the continuation of Julie’s case study.”


Role of Enzymes in The Digestive System: An Analogy

Okay, it may be a bit of a stretch but bear with me, as I compare the enzymes used in the digestive process with the saws used in a sawmill. Surprisingly there are a lot of similarities between the two.For instance, a sawmill takes large trees and cuts them into smaller useable forms of wood like plywood, two by fours, and even paper, right?

340px-Digestive_system_diagram_edit.svgWell, the digestive process does this with food.

At the top of this “digestion assembly line” your mouth produces saliva to begin the breakdown process. The food then drops into the stomach. The presence of food in the stomach turns on even more secretion of acid in the stomach. This acid activates the enzymes that can then go to work on the food.

In the sawmill, there are different saws used to create the different kinds of wood, or wood products. The digestive system equivilent are enzymes and acids. The acids first breaks the food up in preparation for the specific cuts that the enzymes make.

For the digestive process there are three basic cuts needed and these correspond to the types of food molecules that need to be separated.  The digestive system uses:

  • proteases for proteins,
  • lipases for fats, and
  • amylase and sucrase for carbohydrates

There are other specific types of enzymes needed within each of these categories. For instance there are several types of proteases and amylases. There are specific enzymes needed for fiber breakdown, cellulase, hemicellulase, etc.  Sound anything like a sawmill to you? In the section below we will look at the specific role of enzymes in the digestive system.



Role of Enzymes In the Digestive System


The Stomach

The enzymes in the stomach are activated by the acid. As noted above, the acid is produced when food is broken down in the mouth and from smells and visual stimulation of food.  Further acid secretion occurs when the stomach is stretched from the food. The acid produced is called hydrochloric acid and is produced by cells called parietal cells. In the presence of the acid the enzymes become activated and can then go to work on the food there.  The bulk of the enzymes in the stomach are proteases, mainly Pepsin, and they begin to cut the large bonds in the foods. By the way, even foods that are not rich in protein like pasta still have protein bonds.

In this way, the hydrochloric acid and enzymes of the stomach do the non-specific cuts and deliver the partially processed food to the small intestine.


Small Intestine

The process of breaking down foods is not a simple as we might think. The enzymes only work under certain conditions which are mostly related to PH. PH is a term used in chemistry used to differentiate the level of acidity of a liquid. In the stomach the proteases there are active under high acidic environments. However the proteases in the the small intestines are only active in low acid environments. Not to worry since the body has this all thought out already. PH balanced enzymes is an important factor to note when using digestive enzymes to enhance the digestive process. If they are not PH balanced, they will be less effective.

In the small intestine, the presence of the highly acidic substance from the stomach causes the release of a hormone called Secretin.  Secretin then passes through the blood to the pancreas and  triggers the pancreas to secrete Bicarbonate.  The presence of bicarbonate in the small intestine raises the PH, so the enzymes here can work properly. The enzymes used here for carbohydrate breakdown are maltase, sucrase, lactase and other various forms of amylases. These are all secreted by the pancreas along with proteases.

When there is fat in the food content, another hormone called CCK is sent to the pancreas by way of the blood stream. It is the fat itself that stimulates the body to produce the CCK. This hormone causes a release of lipase into the small intestine. Lipase is a specific enzyme needed to breakdown fats but it cannot do this all on it’s own. CCK also goes to the gall bladder and tells it to release bile into the small intestine. Bile is need to emulsify fats so the lipase’s can actually get at and around the fat particles. Without bile the lipase’s can only work on the outside of the fat particles which is a highly inefficient process. Together bile acids and lipase can swiftly process large amounts of fat from foods like steak, avocado, coconut oils, etc.

Additional information on the role of enzymes in the digestive system

Symptoms of Digestive Enzyme Problems

  • Gas bloating
  • Fatigue
  • Food Sensitivities
  • Diarrhea
  • Constipation, and
  • Other digestive system problems

Please note that the above list of symptoms can be caused by several problems not only digestive enzymes. Knowing the role of enzymes in the digestive system will help you narrow down the cause of your symptoms. Perhaps equally important is the mucosa or absorptive areas of the digestive tract. In the next section we will look at how the food particles actually gets into the body.

Join us in Lesson 3: Absorption of Food

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