Basic Considerations In Food Combining By
Virginia Vetrano, B.Sc.
The Hygienic rules of food combining are based on certain facts of the physiology of digestion that are well-known to the orthodox biologist and physiologist. Although these specialists in science never make any effort to make a practical application of their knowledge to the everyday task of living, the known limitations of the digestive enzymes make it important that some consideration be given to these in our eating habits.
What I have to say in the remainder of this article is based squarely upon the current teachings of standard physiologies, as I learned them in my studies of science prior to my graduation, but a few weeks ago, from the University.
The human digestive tract is divided into three cavities: the mouth, the stomach and the intestines. Each of these cavities possesses its own characteristic digestive juice or juices with which to do the digestive work of the particular cavity. Thus the work of digestion may be divided into three steps or stages, the work of each cavity preparing the food for the advanced work of the next.
Although physiologists and biologists tend to think of salivary and gastric digestion as relatively unimportant, many facts, which I shall discuss in a future article, indicate that the efficiency and satisfactoriness of intestinal digestion depend upon the thoroughness with which salivary and gastric digestion have been carried out. With this thought in mind we shall begin our studies of the digestive processes.
Digestion is essentially a process whereby large molecules are broken down into smaller molecules by the process of enzymatic hydrolysis. Hydro (water) lysis (to loosen), means to loosen up by water, or to cleave large molecules into smaller ones by adding water. The organic catalysts (enzymes) are necessary to speed up hydrolysis. Without enzymes, very high temperatures and strong chemicals are necessary to produce hydrolysis, but these destroy food values.
In the stomach hydrolysis occurs in comparatively low temperatures and in a short while. The thesis is that it takes a year or more to hydrolyze foods without enzymes. Unfortunately the end-products are never really the same. Thus we see that enzymes are of primary importance in digestion.
Without chemical digestion, the animal organism would derive no benefit from foods. The food must be reduced to the size necessary to pass through the mucous membrane of the intestine and it must be changed into substances that can be assimilated and used by the organism, such as simple sugar, resulting from carbohydrate digestion; glycerol and fatty acids, derived from the fats of our diet; and amino acids, derived from proteins. Without good digestion we rob ourselves of many important elements and permit decomposition and putrefaction which cause various and sundry troubles.
Enzymes are organic catalysts composed of complex protein; hence, the requirement of amino acids for their synthesis. (A catalyst is a chemical agent that, when added to reacting chemicals, greatly speeds up their reaction and may be recovered practically unchanged at the end of the reaction.) The vitamin molecule is also said to form part of the enzyme molecule.
There are extracellular enzymes (exoenzymes), such as the digestive enzymes, and glycogenase, found in the liver, is an example. Exoenzymes are secreted from the cells that produce them, and they perform their activities outside the cell. Endoenzymes do their work inside the cells that produce them.
Each enzyme is specific in its action; by this is meant that it acts upon one class of food only (fats, carbohydrates or proteins) and upon no other, or upon one class of products of previous enzymic activity. Indeed, each one of the different sugars requires its own specific enzyme. They perform their work best at body temperature.
Each enzyme is capable of acting only in a medium of a certain pH. The pH of a substance is the measure of its acidity or alkalinity. An alkaline substance is one in which the hydroxyl ions (OH) are in excess of the hydrogen ion (H). If the hydrogen ions are in excess, the substance is acid. If the hydroxyl and hydrogen ions exist in equal concentrations, the substance is neutral.
For convenience, the physiologist expresses the concentration of hydrogen ions with the chemical symbol pH. Measuring the relative concentration of hydrogen and hydroxyl ions with the potentiometer, substances with a pH of seven are neutral, becoming increasingly acid as the pH falls from seven to one and increasingly alkaline as the pH rises from seven to fourteen.
Enzymes exist in an inactive form designated as proferment or zymogen, within the cells that produce them. Some may remain inactive until activated by activators (an inorganic activator) and kinases (organic activators). Others are converted into active enzymes at the moment of secretion.
There are also coenzymes, where the action of an enzyme is dependent upon the presence of another substance as in the case of the dependence of pancreatic lipase upon bile salts. It was formerly thought that bile has an antiputrefactive action, but it is now thought that the greater amount of putrefaction of proteins and carbohydrates in the absence of bile is due to the fact that fats are not digested off the food, thus protecting them from the digestive juices.
This allows the foods to undergo bacterial decomposition, the end-products of which are toxic. The above should indicate the importance of not eating fried foods and of not saturating your bread, potatoes, and other starch with butter, margarine, oil or other fat.
Food, upon being received in the mouth, is subjected to communition and insalivation and is thus reduced to a soft mass known as a bolus. The first enzyme with which the bolus comes in contact is ptyalin or salivary amylase. This enzyme begins starch digestion, changing the starches to dextrine and maltose, if given sufficient time to continue its action in the stomach. I shall speak more of this later. The bolus acquires a neutral or slightly alkaline reaction that is essential to the continued action of the salivary amylase. If the saliva is distinctly acid, it immediately stops salivary digestion and the first step in converting starch into usable sugars is arrested.
After food has been masticated and insalivated, the bolus is sent through the esophagus to the stomach where gastric juice is poured out in large quantities (an average of 1.5 to 2.5 liters a day). It is a thin, colorless fluid with a definite acid reaction (pH of 0.9 to 1.7), containing protein, mucin, inorganic salts, about five percent hydrochloric acid, and the enzymes pepsin and gastric lipase. If no protein is eaten, the juice is almost neutral in reaction.
Shortly after food enters the stomach, contractions begin in the middle region, passing down to the lower end called the pyloris. These actions thoroughly macerate the food with the gastric juice, forming the thin liquid mass now called chyme. The fundus or upper end of the stomach exerts pressure on the food in it so that it constantly pushes the food further into the more active or prepyloric and pyloric end of the stomach.
In thin way, all the contents of the stomach become a liquid chyme and are thoroughly mixed together. There can be no separation in the stomach of one part of the meal from the other. A blender also has the churning action only at the bottom but shortly after the motor is turned on all the contents are thoroughly and evenly mixed. The churning motion in the lower part of the stomach, the addition of an enormous amount of fluid, plus the constant pressure of the fundus, (which the blender lacks) upon the food is more than enough to ensure the thorough maceration of the food.
As previously stated, the enzymes of the stomach are pepsin, and gastric lipase. Pepsin, which initiates protein digestion, requires an acid medium in which to work. It is secreted as the zymogen pepsinogen and rendered active by the hydrochloric acid of the gastric juice. Pepsin is active only in the presence of hydrochloric acid and the hydrochloric acid may be destroyed by alkali such as baking soda, etc. Pepsin hydrolyzes proteins through several stages into proteoses and peptones, which are inabsorbable and must undergo further hydrolysis in the intestine by other proteolytic (protein splitting) enzymes.
The stomach enzyme, gastric lipase, asserts its activity upon fats, breaking them up into fatty acids and glycerols, but the action of this enzyme is inhibited by an acid medium. Physiologists believe that fats undergo little or no digestion in the stomach because of the acid gastric juice, but Hygienists have shown that, with proper combinations, fats can be digested in the stomach.
The very fact that a fat-splitting enzyme is contained in the gastric juice, indicates that it is there for a purpose and, if in a medium of the right pH, it will exercise its properties. Fats and proteins are a very bad combination since proteins require a very acid medium for digestion and this would inactivate gastric lipase. Fats also inhibit gastric secretion, it is thought possibly by the production of a hormone called enterogastrone.
But where fats are eaten with green vegetables, preferably raw, the inhibiting effect of fats on gastric secretion is counteracted and protein digestion proceeds quite normally.
Salivary digestion or the action of ptyalin or salivary amylase upon starches occurs while chewing and swallowing food and for a brief time after it gets into the stomach. This is not sufficient time to complete salivary digestion. Unless starch-protein combinations are avoided, salivary digestion of starch is not completed. We have learned that pepsin, that acts on proteins, needs an acid medium in which to work, and salivary amylase, that digests starches, needs an alkaline medium.
Then, if protein foods, such as nuts, cheese, etc., are eaten with starches, such as potatoes or bread, the gastric secretion will be acid because of the presence of the protein food, and will speedily bring to a halt all starch digestion in the stomach. The starchy food will be left incompletely digested until it reaches the small intestine for further hydrolysis, providing it has not undergone fermentation and decomposition.
It must be remembered that it is during this waiting period, because of the temperature of the stomach, that fermentation and decomposition are most likely to occur. The end-products of bacterial decomposition are always poisonous.
When a starch is eaten alone, that is without protein, as for example, a potato, a gastric secretion, the pH of which is practically neutral, is poured into the stomach, and salivary digestion will combine in the stomach uninhibited. Other acids besides hydrochloric acid destroy salivary amylase.
Free acids of fruits, such as those of oranges, grapefruit, pineapples, tomatoes, lemons, limes, sour apples, sour grapes, sour berries, etc., and the acid of vinegar as well as drug acids, destroy salivary amylase. The eating of acid fruits and the taking of vinegar-containing dressings suspends salivary digestion. The drinking of orange or tomato juice with the starchy breakfast cereals that conventional eaters consume, is hazardous.
Salivary and gastric (stomach) digestion, if carried out properly, prepares the food for intestinal digestion, where enzymes of the succus entericus (the secretion of the intestinal glands) and the pancreatic juice and the coenzymes of the bile take over. In the intestine, the end-products of hydrolysis are reached and the food is ready for absorption, which also takes place in the intestine.
Succus entericus, the intestinal secretion, contains four or five enzymes and has a marked alkaline reaction. The enzymes are as follows: enterokynase, which activates trypsin (the protein-splitting enzyme of the pancreatic juice); erepsin, which completes the work of pepsinand trypsin, hydrolyzing peptides to their constituent amino acids. The hydrolyzing enzymes of the succus entericus hydrolyze disaccharides, which are double sugars, into monosaccharides, which are simple sugars such as glucose and fructose.
Without the hydrolyzing enzymes, to convert disaccharides to monosaccharides, the disaccharides would be eliminated by the kidneys because as such they are non-usable by the tissues.
Maltase acts upon maltose, and dextrine, which are products of the salivary digestion of starches. Two other hydrolyzing enzymes are sucrase, which hydrolyzes sucrose to glucose, and fructose, and lactase, the milk sugar enzyme. Sucrose is cane sugar, but it is also found in vegetables, the juices of many plants and some fruits. Most fruits contain the monosaccharides glucose and fructose.
(If combined properly, fruits are the easiest of foods to digest, because their sugars are already in an assimilable form, needing no further hydrolysis. They need only to be absorbed and used.) Lactase acts upon milk sugar (lactose), hydrolyzing it to glucose and galactose.
Other constituents of the succus entericus are nuclease, which hydrolyzes the nucleic acid components of neucloproteins and secretin, which is a hormone that I need not discuss in this short article.
Bile serves many important functions in the small intestine. It is an alkaline fluid, pH about 6.8 to 7.7, consisting of water, bile pigments, bile acids, bile salts, cholesterol, lecithin and neutral fats. Secretion of bile in the liver is continuous but it enters the duodenum only when chyme is present.
Bile may be considered a coenzyme of pancreatic lipase as pancreatic lipase combined with bile splits fats more rapidly than it does alone. Bile helps in the absorption of fatty acids by combining with them, making them more soluble, hence more easily absorbed. Bile is needed in facilitating absorption of many fat soluble vitamins, especially vitamins D, E and K. Bile has many other functions not concerned with digestion.
The pancreatic fluid enzymes are trypsis, pancreatic amylase and pancreatic lipase. Trypsinhydrolyzes proteins into proteoses, peptones and polypeptids and, given enough time, under favorable conditions, will continue its action until the necessary amino acids are reached. The more efficient and complete peptic digestion has been in the stomach, the more likely will trypsin and erepsin be able to complete the hydrolysis of proteins.
Normally, proteins should be hydrolyzed into proteoses and peptones by gastric digestion. Under favorable conditions, proteins may be passed into the intestine without peptic digestion. Physiologists think that the enzyme trypsin of the pancreatic juice can initiate protein digestion and may reduce these proteins to proteoses and peptones, polypeptids, dipeptids and, finally, amino acids.
It is reasonable, however, to think that thorough peptic digestion of proteins before they are expelled from the stomach assures the completion of their hydrolysis in the intestine, thus avoiding putrefaction.
The Hygienist does not agree with the thought of physiologists that salivary and gastric digestion are unimportant. The thoroughness with which enzymes do their work depends upon the amount of time they have in which to work. Obviously, therefore, thorough peptic digestion of protein will shorten the time required for the completion of protein hydrolysis in the intestine.
The several enzymes of the pancreatic and intestinal juices that complete the digestion of proteins, carbohydrates and fats in the intestine, function only in an alkaline medium. The chyme from the stomach is acid, but bile from the liver and the pancreatic juice, both of which are alkaline, quickly provide an alkaline environment for the action of the enzymes in the intestine.
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We need not concern ourselves with combinations, as they relate to intestinal digestion, except to point out that the best preparation for intestinal digestion is good salivary and gastric digestion. Food combining is, therefore, of greatest importance as it relates to salivary and gastric digestion.
Dr. Vetrano recommends using as little soaking water as possible, soaking one side at a time, so all water will be absorbed, thus avoiding losing flavor and nutrients. It is important that the water used for soaking be distilled water. If any water remains after soaking the fruit, you can drink the water.
Sweet fruits combine fairly well with subacid fruits, provided the subacid fruits are on the “sweet side,” for example, use Delicious apples, not Macintosh, or Jonathans, with sweet fruit.
It is best to have these fruits at a fruit meal combining only with lettuce and/or celery. Since fruits are usually high in acids or sugars, they do not combine well with other foods.