Basic Digestion Principles

Digestion of foods that you eat or drink, begin in the mouth.  When you chew, your food is mixed with saliva.  An enzyme secreted from the saliva, called ptyalin (amylase), starts the digestion of starch into maltose and glucose (sugars).  This is one reason why it is very important to chew your food at least twenty times before swallowing.  It is also highly recommended to chew on liquids (juicing/juices) to start the digestive process.  In doing so, the body will have an easier time digesting starches more efficiently. (Remember, digestion is the hardest thing your body does).   This digestive process (starches) will continue for an hour before the gastric secretions (Acid production) block amylase activity in the stomach.  This occurs when the pH of the stomach goes below 4.0.

The next step in digestion is the breakdown of proteins.  This is accomplished by the release of hydrochloric acid (HCL) by the parietal cells.  HCL then acts on pepsinogen to convert it to pepsin (the important peptic enzyme of the stomach).  Pepsin’s active pH range is 2.0 to 3.0 and inactivates above a pH of 5.0. 

HCL pH is .8 and by the time foods and saliva mix together the pH is around 2.5 on average.  This is why you must limit the amount of liquid you drink with a meal to no more than 8oz’s.  Optimally, it is best not to drink with your meals.  Drink an hour or so after your meals and 30 - 45 minutes before your meals.  The more liquid that goes in, mixes with the gastric juices and the pH starts to go up and eventually out of the optimal pH range of the pepsin, thus protein metabolism starts to stop.

The next phase of digestion takes place when the stomach starts to empty its content into the upper portion of the small intestines.  The pancreas releases proteolytic enzymes called trypsin, chymotrypsin, carboxypolypeptidase, and proclastase. Even the micro villas of the small intestinal track digest proteins via aminopolypeptidase and dipeptidase.

Fat digestion actually begins in the mouth by lingual lipase that is secreted by the lingual glands.  (Remember to chew your food several times).  Fats must be emulsified to be broken down.  This is accomplished by bile.  Bile is produced in the liver and stored in the gallbladder.  When fats enter the small intestines, bile is released which consist of bile salts and lecithin of which both start to emulsify fat into smaller particles.  The pancreas dumps an enzyme called lipase out to break down fat.  The bile salts react with fat to create micelles, it is in this type of suspension that the micelles pass through the brush borders of the intestinal lining to release triglycerides into the blood stream.  The bile salts are released back into the intestines to repeat this process over and over again. 

Carbohydrate digestion starts in the mouth and continues in the upper portion of the small intestines.  The pancreas releases amylase and almost totally converts the carbs into maltose and other small glucose polymers.  Then the enterocytes in the villi of the small intestines contain lactase, sucrase, maltase, dextrinase.  These enzymes break down the various forms of sugar, (Lactose beaks down to galactose and glucose, sucrose breaks down to fructose and glucose, maltose breaks down to glucose) thus, the end stage of carbohydrate digestion and the release of glucose into the portal blood.  Side note: Fructose (fruit sugar) has to be processed by the liver before it can break down to glucose, thus a slower rise in the glycemic index).

Remember to chew your food until it is in a more liquid state:  This takes stress off the digestive system and you are more likely to absorb more nutrition and you will eat less.

Eat in a relaxed environment:  Your body can not digest properly when it is under stress.

Wait an hour before doing physical activity if possible:  Digestion is the hardest thing the body does.  When you eat on the run or do physical activities right afterwards, you will divert blood from the digestion system to your extremities.  This takes your body from a parasympathetic state (rest and rebuild state) to a sympathetic state (fight or flight). When this takes place, digestion gets put on a lesser priority, thus leading to improper digestion.

We are living being’s, so we need to be eating more raw foods.  Raw foods contain digestive enzymes in them to help our body’s break them down.  When we eat dead food (cooked, preserved, fried, etc.) our body must respond to the enzyme needs.  This constant demand on our body is one of the beginning processes that leads to premature degeneration as we age, because we are taking away from our enzyme bank that we were born with.