In the first two articles we learned:

• Enzymes can be grouped into three categories: metabolic enzymes, digestive enzymes and food enzymes.
• Enzymes are proteins that function as 'catalysts' or 'accelerators' in the body.
• All biochemical reactions within the human body, including energy production, metabolism, reproduction, the immune system, and the digestive system utilize enzymes.
• 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.
• Metabolic enzymes are the enzymes made within the cells of the body to perform specialized tasks required for life and health.
• 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 the next article - food enzymes and how these food enzymes can be used to optimize digestion.