Digestive Enzymes
In the articles What are Enzymes & Metabolic
Enzymes, we learned that :
1) Enzymes are proteins that function as 'catalysts' or
'accelerators' in the body.
2) All biochemical reactions within the human body, including
energy production, metabolism, reproduction, the immune system,
and the digestive system utilize enzymes.
3) There are thousands of different enzymes that regulate
bodily functions and these body functions would not be possible
were it not for enzymes. Simply put, without enzymes, life
could not exist.
4) Enzymes can be grouped into three categories: metabolic
enzymes, digestive enzymes and food enzymes.
5) Metabolic enzymes are the enzymes made within the cells of
the body to perform specialized tasks required for life and
health.
6) We must be sure that nothing interferes with the body making
enough of these highly-specialized metabolic enzymes by
minimizing exposure to toxins and providing the body with all
the nutrient co-factors necessary for these enzymes to function
optimally.
This article is dedicated to the topic of digestion and the
specialized digestive enzymes that make this happen. No matter
what we eat - whether it is vegetables, pizza, fruits, salads,
chicken or any other food - we consume essentially three basic
bulk food materials: protein, carbohydrates and fats. Before
the body can utilize the protein, carbohydrates and fat, these
large complex macromolecules must be broken down into smaller
and simpler substances. This process - the process of breaking
down food complexes into the simple nutrient substances the
body needs - is digestion. If digestion does not occur, the
nutrients in foods remain trapped in the food and never become
available to the body for all its various functions - making
new cells, tissues, hormones and creating and activating the
metabolic enzymes.
The fact that the body can't receive any of the essential
nutrients required for metabolic function without proper
digestion highlights the critical role of digestion and
digestive enzymes in the health and function of the body.
Unfortunately, most people take it for granted that the food
they place in their mouths will be digested, absorbed and
assimilated into the body's cells. Most people are totally
unaware that without digestive enzymes, their cells would
literally starve. Digestion only takes place as the result of
the interaction of enzymes with the complex molecules that make
up food. In other words, enzymes make digestion possible.
No nutrient becomes available to or utilizable by cells
unless digestive enzymes do their job in transforming the food
into a form the body can use. This transformation must result
in nutrients that are small enough to pass into the blood
through the minute channels of the intestines and are in
chemical forms acceptable to, and utilizable by cells and
tissues.
The process of breaking down foods into utilizable forms
happens in stages and requires different enzymes for each
component of the food. The first stage actually begins with the
chewing of food. Under the best circumstances (as with eating
raw food), the chewing pulverizes the cellular material of the
food and releases the enzymes contained in the food. The
enzymes immediately begin the process of digestion of the
nutrients contained within the food. In addition, as chewing
begins, the food is bathed in saliva, which also contains
enzymes. Saliva is especially rich in the enzymes that break
down starch or carbohydrate, called amylase.
The importance of this feature of digestion is often
overlooked. Yet, it is the primary reason behind the
traditional wisdom of chewing your food thoroughly before
swallowing. Both food and the body's own secretions within the
digestive tract contain enzymes and both types of enzymes
assist in this early stage of digestion.
Food and salivary enzymes can digest 60 percent of starch
(carbohydrate), 30 percent of protein and 10 percent of fat in
stage 1 and the beginning of stage 2, even before the body's
other secretions become active. To whatever extent enzymes are
missing, however, that stage of digestion will be
incomplete.
Consequently, the digestive process in the subsequent steps
will be slowed down significantly or never take place at all.
If this happens, undigested food will be exposed to the small
intestine and may not be absorbed, resulting in lower energy
levels, less nutrient availability and potential food
allergies.
Continuing on with the digestive process, as soon as the
food is chewed, digestion continues as it travels to the
stomach where the second stage of digestion begins. In the
stomach, the food is exposed to stomach juices including
hydrochloric acid (HCL). This acid slowly causes the pH to
become very acidic and is a vital function in the digestive
process. The stomach may require as long as one hour to reach
its most acidic condition. During this time, the enzymes from
saliva and food continue to digest food. As the stomach reaches
its low pH level, the enzymes from saliva become inactive, and
another acid-active enzyme called pepsin is secreted.
Pepsin performs a critical role in the digestion of protein,
but is only active in an acid environment. Individuals who use
acid-blocking medications can inactivate this important enzyme
and disrupt digestion.
After the food has been substantially digested, it moves
into the small intestine. This is considered the third stage of
digestion and begins in the duodenum (the first section of the
small intestine). Here, juices from the liver and gall bladder
secrete an emulsifying agent called bile. It is the bile and
bile acids, as they enter the duodenum, along with enzyme
secretions from the pancreas, that continue the breakdown of
nutrients. These secretions also contain alkalizing chemicals,
known as bicarbonates, which help neutralize acids left over
from the stomach and bring food into a slightly more alkaline
range. This process is extremely important because pancreatic
enzymes are only active when in the slightly alkaline medium
that occurs during this stage.
It is in this stage of digestion that the enzymes secreted
by the pancreas - lipases, proteases, peptidases and amylases -
do most of their work to complete the conversion of food into
usable nutrients.
- Lipases digest fats
- Proteases and peptidases complete the protein digestion that
was started in the stomach.
- Amylases complete the digestion of sugars and starches.
After the digestive process in the duodenum has done its job
and the food is in its simplest form, the digestive process
proceeds to the next portion of the small intestine, called the
jejunum, where the final step occurs. The jejunum is almost
exclusively devoted to the function of nutrient absorption. If
digestion has been efficiently performed up to and through this
final stage, the only remaining residue should be fibrous
material and non-nutritive portions of food.
When all of the stages of digestion are completed properly
with all the necessary enzymes, the body receives the nutrients
it needs to function. When digestion doesn't occur properly,
the body will not receive all of the nutrients it needs.
Hopefully, you no longer take digestion for granted and you are
now asking yourself, "How can I make sure that digestion occurs
properly?" That question will be answered in our next article
when our Enzyme Series will discuss food enzymes and how these
food enzymes can be used to optimize digestion.
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