Digestion in the Stomach

Digestion begins in the mouth When you chew your food it is mixed with saliva, which not only supplies moisture but also the carbohydrate-digesting enzyme, amylase. When you eat raw food, its enzymes work with the salivary amylase to begin digestion.

Swallowing prevents food from remaining in the mouth long enough for any significant amount of digestion to occur. However, the food and salivary enzymes continue the digestion process until the secretion of stomach acid causes the pH to drop below 3.0, which is the activity range of plant enzymes. Before food arrives, the stomach normally has a pH between 5.0 and 6.0. In young and healthy adults it takes about 45 minutes before enough acid is generated to drop the pH to 3.0. This is because stomach acid is secreted into the stomach in response to the expansion of the stomach wall. During this time a considerable amount of digestive work can be accomplished if plant enzymes, either indigenous to the raw food ingested or from a supplemental source, are present. Unfortunately, the amount of time necessary to make stomach acid increases with age. Studies have proven that older adults often suffer from inadequate stomach acid levels.

There is a common misconception that enzymes are destroyed by stomach acid. Nothing could be further from the truth. Stomach acid does not digest protein. Rather, it activates an enzyme called pepsinogen which then becomes pepsin that is secreted by the stomach wall. This enzyme is only active within the pH range of 3.0 to 5.0 and requires the acid to maintain that pH. Pepsin is very specific in its action and is simply incapable of digesting food enzymes, which are very large molecules and are more than just protein.

More than seventy years ago, Olaf Bergeim conducted a series of experiments on salivary digestion at the Laboratory of Physiological Chemistry in the University of Illinois, College of Medicine in Chicago. He found that an average of 59-76% of ingested carbohydrates is digested within 15-30 minutes after a meal. He concluded that a very considerable degree of starch digestion may be brought about by saliva if food is chewed properly.

The pH within the stomach rarely, if ever, drops below 3.0. Pure stomach acid has a pH of 1.8 when it first enters the stomach, but is quickly diluted in the presence of food. Regardless, plant enzymes are not destroyed by the highly acidic environment of the stomach. They simply become dormant until reaching the higher pH levels in the small intestine, where they again become active and continue the digestive process. Once their digestive function in the gastrointestinal tract is completed, a large number of enzymes are absorbed through the gut wall into the bloodstream.

A lot of research remains to be done to determine the exact fate of these enzymes after they pass through the gut wall into blood. However, it is known that plant enzymes will pass from the body into the urine after they have completely lost their usefulness.

What Do Plant Enzymes Do?

Along with vitamins and minerals, enzymes occur in food that is in a natural state. All raw food contains the proper types and proportion of enzymes necessary to digest itself. This occurs in our stomach when the food is eaten or in nature as the food ripens.

The type (protein, sugar, starch, fat) and amount (caloric value) of the major components present in the food determine the type and amount of the various enzymes found in the food. For example, olives and bananas are higher in fat and lipase, while peaches are higher in carbohydrate and amylase.

Protein, carbohydrates, fat, and fiber are building blocks but they do not possess the energy (capacity to do work) necessary for biochemical reactions. Only enzymes can furnish this energy. When raw food is eaten, chewing ruptures the cell membrane and releases the indigenous food enzymes. Once liberated the enzymes begin to digest food, but their action is very limited in the foods they can work on.

Four plant enzyme groups exist:

1.       Proteases - break long protein chains into smaller amino acid chains and eventually into single amino acids

2.       Amylases - reduce polysaccharides to disaccharides: lactose, maltose, and sucrose

3.       Lipases - break triglycerides into individual fatty acids and glycerol

4.       Cellulases - digest specific carbohydrate bonds found in fiber

Besides needing a substrate to "work" on, enzymes require heat, proper pH and moisture in order to activate.

Heat: All enzymes work within limited temperature ranges. The optimal temperature range for most plant enzymes is 92˚F to 104˚F, which means that these enzymes work best at body temperature. However, enzymes cannot tolerate the high temperatures used in cooking, baking, microwaving, canning, and pasteurizing. These methods all produce heat of 118˚F or higher which destroys the enzymes.

Proper pH: Plant enzymes work in a very broad pH range, 3.0 to 9.0, which coincides very nicely with the human gastrointestinal tract. This is an important factor to remember when comparing plant enzymes with the body's own digestive enzymes or with supplemental animal enzymes, such as pancreatin. Plant enzymes work in both the stomach and intestines. Pancreatic enzymes, whether produced by the body or provided as a dietary supplement, only work in the small intestine.

Moisture: Plant enzymes must have moisture in order to perform their digestive function. Quite simply, digestion is the process of breaking molecules apart with the addition of water hydrolysis. The body satisfies this need with saliva. Conversely, plant and animal cells use the process of condensation—the removal of water—to form the long molecular chains that foods are composed of.

Why Food Enzymes are Important

Plant enzymes are important because they are capable of digesting food before the body’s own digestive process begins. In other words, plant enzymes can enhance the digestion of food and the delivery of nutrients to the blood even if you have a compromised digestive system. The same cannot be said of animal enzymes such as pancreatin.

Everyone agrees that proper nutrition is crucial to the maintenance of a healthy body. However, most health care practitioners overlook the true cause of many nutritional disorders. It is assumed, quite mistakenly, that digestion occurs automatically and the correction of a nutritional disorder simply requires matching the right nutritional supplement to the condition. For example, vitamin C for colds, vitamin A for viruses and herbal laxatives for constipation. While this treatment may relieve patient symptoms, the relief is only temporary because the underlying problem of faulty digestion is ignored. Health care practitioners who want to effectively manage health problems that are related to nutritional imbalances must consider each person’s ability to digest food. Unfortunately, most clinicians give little or no thought to the role of enzymes in digestion, despite overwhelming evidence of their importance.

Enzymes are present in all living animal and plant cells. They are the primary motivators of all natural biochemical processes. Life cannot exist without enzymes because they are essential components of every chemical reaction in the body. For example, they are the only substance that can digest food and make it small enough to pass through the gastrointestinal mucosa into the bloodstream. Three very broad classifications of enzymes are:

1.       Food enzymes - occur in raw food and, when present in the diet, begin the process of digestion

2.       Digestive enzymes - produced by the body to break food into particles small enough to be carried across the gut wall

3.       Metabolic enzymes - produced by the body to perform various complex biochemical reactions

In the 1930s, Edward Howell, MD, the food enzyme pioneer, found that there is a difference between plant enzymes and those that are produced by the body. He was convinced that plant enzymes in food and supplements have a different function in human digestion than that of the body’s own digestive enzymes. With this theory, he began isolating and concentrating plant enzymes from their sources. He found the difference is that food enzymes begin digesting food in the stomach and will work for at least one hour before the body’s digestive system begins to work. For this reason, enzymes should be considered essential nutrients. Unfortunately, this is not the case, and food manufacturers are removing them from food to gain shelf-life.

Dr. Howell was particularly impressed by the way the ingestion of raw food slowed the progress of chronic degenerative diseases and spent his professional life postulating and then validating his theories.

Indigestion

Indigestion is perhaps the most common ailment affecting people today. A multi-billion-dollar-a-year industry has emerged to provide over-the-counter remedies to sufferers. Why do so many people suffer from indigestion and why don’t traditional remedies for indigestion correct the problem rather than merely provide temporary relief from its symptoms? The reason is that digestion is a very complex process.

It is very difficult to know exactly which step in the digestive process is at fault. The symptoms of indigestion and other digestive problems such as heartburn, gas, bloating, nausea, and cramps are vague and there are no lab tests to define the exact problem.

Indigestion has many causes. One of the most common causes is a deficiency in stomach acid (HCl). This inability to produce adequate stomach acid is common in people over 50 years of age who are free of gastric disease. Some studies even report as high as 25-35% of the elderly have this condition.

The lack of acid (HCl) secretion in the stomach was found in 14-20% of patients in the hospital for conditions other than gastric disease or pernicious anemia. This condition is diagnosed when the pH of the gastric contents fails to drop below 6.5 following maximal stimulation. The “resting pH” of the stomach, when empty, is normally 5.0 to 6.0.

HCl is critical for proper protein digestion in the stomach because it adjusts the pH of the stomach to allow protein digestion to occur. HCl changes pepsinogen to the active proteolytic enzyme, pepsin, and maintains the highly acidic pH needed for pepsin’s activity. Stomach acid activates this enzyme, it does not destroy it.

The secretion of HCl and pepsinogen are governed by separate mechanisms. This is the reason that the pepsinogen concentration in the gastric juices of those who are lacking stomach acid is very close to normal in many cases.

Physiologists have confirmed that HCl is produced from one cell and pepsinogen is produced from another. This means that the body may be producing enough pepsinogen but it is still unable to properly digest protein because of an insufficient amount of HCl.

So, what can be done to improve digestion and relieve the symptoms that result when the body cannot produce adequate amounts of stomach acid? The answer is enzymes. Protein digestion can be improved with food enzymes that “predigest” food in the stomach. Plant enzymes are capable of digesting food before your own digestive process begins. In other words, plant enzymes can enhance the digestion of food and the delivery of nutrients to the blood even when the patient has a compromised digestive system.