The Digestive System

Hello again!  I hope you're feeling well after yesterday's feast! :)  Did anyone experience upset stomach, indigestion, gas, or bloating?  I hope not, but would also not be surprised to hear some people say, 'yes.'  There is a very good reason why you may have felt one or a few of those symptoms.

I would like to first give an overview of the GI (gastrointestinal) tract since that is one of the chief complaints among people.  According to my literature in my holistic studies, the most common reason for hospitalization among 15-44 year olds is digestive disorders.  Between the ages of 45-65, digestive problems become the second most common reason for hospitalization.

Later, I will go into more detail of the various common ailments of the GI tract.

Let's first understand how our intricate system works.

At its simplest, the digestive system is a tube running from mouth to anus. Its chief goal is to break down huge macromolecules (proteins, fats and starch), into smaller molecules (amino acids, fatty acids and glucose) that can be absorbed across the wall of the tube, and into the circulatory system to be used by the cells throughout the body. You will hear me refer to "cellular nutrition" throughout the blogs, because cellular nutrition is what feeds our body's organs.

The digestive system can be divided into two main parts: the alimentary tract and the accessory organs. The mouth, pharynx, esophagus, stomach, small and large intestines, rectum and anus make up the alimentary tract .  The salivary glands, liver, gallbladder, and pancreas make up the accessory organs.

Digestion begins in the mouth as food is chewed and mixed with our saliva.  Carbohydrates and proteins are digested differently.  Carbohydrate digestion starts in the mouth when the digestive enzyme, amylase, present in the saliva, starts to break down the food as you chew.  Once you swallow the food and it enters the acidic environment of the stomach, amylase stops working.  Only when the food leaves the stomach and enters into an alkaline environment do we get the next wave of amylase enzymes which are secreted by the  small intestine and pancreas.  This is where the digestion of carbohydrates are completed.    ~~~    Protein on the other hand is not digested in the mouth at all.  It needs the acid in our stomach in order activate the protein-digesting enzyme pepsin.  The protein food may hang out in our stomachs up to three hours until all the complex proteins are broken down into amino acids known as peptides. Once peptides leave the stomach, the pancreas secretes peptidase enzymes which break them down further so the body can utilize them.  There is a lot more that goes into this process but I want to keep it simple.

Fruits are digested relatively quickly, leaving the stomach in about 30 minutes, so it is best to consume fruit on its own as a snack so it doesn't get hung up in the stomach too long causing it to ferment.  So after a meal when you feel like desert, it's best to avoid fruit for this reason.

Can you understand how we can have the symptoms I first asked about?  One reason is the digestion process works differently depending on the types of food we eat, thus it can create an upset in that process if we eat certain foods together.    There are other reasons of course, like not enough stomach acid, deficiencies in certain vitamins, etc.

The Small Intestine has three parts, the duodenum, jejunum and ileum. It receives secretions from the liver and the pancreas, which finalizes the digestion of the nutrients in chyme (the semifluid mass of partly digested food that is emptied by the stomach into the duodenum), absorbs the different products of digestion and moves the remaining residues to the large intestine.  It also consists of cells that secret a variety of substances for the further breakdown of chyme.

The large intestine has four basic functions:   

1. the reabsorption of water 2. the reabsorption of electrolytes 3. the formation of feces 4. the storage of feces

Compared to the small intestine, the large intestine plays a minor role in the digestive process.  The small intestine has glands that secrete a variety of substances but the major substance secreted by the large intestine is mucous and the purpose of the mucous is to protect its walls from materials passing through it (when this happens it's termed "leaky gut"), and for holding fecal matter together.

The liver, gallbladder and pancreas are accessory organs that are closely related to the small intestine.

Liver functions include the following:

• secretion
• synthesis of bile salts
• synthesis of plasma protein
• storage
• detoxification
• excretion
• carbohydrate metabolism
• lipid metabolism
• protein metabolism
• filtering

 The principal function of the gallbladder is to serve as a storage reservoir for bile. Bile is a yellowish-green fluid produced by liver cells. The main components of bile are water, bile salts, bile pigments, and cholesterol.  Bile salts act as emulsifying agents in the digestion and absorption of fats.

When I say the word Pancreas, what do you think of first?  The production of Insulin, right?  Well that it partly right. By the way, did you know that Insulin is a hormone?   The other hormone secreted by the pancreas is glucagon, which is what replenishes the blood sugar if its levels get too low.   Well the pancreas is vitally important in the digestive system because its special cells produce enzymes that break down carbohydrates, fats and proteins.  These enzymes are called amylase, lipase, and protease.  The production of these enzymes depend on many micronutrients, especially vit. B6, so you can see if we're deficient in that particular vitamin, how it can affect a very important organ.     Suboptimum  nutrition often results in suboptimum digestion, which in turn creates suboptimum absorption, so nutritional intake gets worse and worse.   When I say nutritional intake, I am referring to that which is available for the body's cellular use. 

I'll address how you can create balance and optimum organ function by the nutrients you consume.   That is for future blogs.

So that's the digestive system in a nut shell.  Of course a lot more goes into the processing of our food but this gives you a synopsis.

*interesting fact* it takes the stomach and hour to break down cow milk

:)Karen