To make fully clear what combinations of foodstuffs override our enzymic limitations it will be necessary to consider one by one, the possible combination and briefly discuss these in their relations to facts of digestion which we learned in the previous chapter. Such a study should prove both interesting and instructive to the intelligent reader.
In the last chapter we learned that a weak acid would destroy the ptyalin of the saliva. With the destruction of the ptyalin starch digestion must come to a halt. The physiologist Stiles says: “If the mixed food is quite acid at the outset, it is hard to see how there can be any hydrolysis (enzymic digestion of starch) brought about by the saliva. Yet we constantly eat acid fruits before our breakfast cereal and notice no ill effects. Starch which escapes digestion at this stage is destined to acted upon by the pancreatic juice, and the final result may be entirely satisfactory. Still it is reasonable to assume that the greater the work done by the saliva, the lighter will be the task remaining for other secretions and the greater the probability of its complete accomplishment.”
Howell says it appears that: “this lipase is readily destroyed by an acidity of 0.2 per cent HCI, so that if it of functional importance in gastric digestion its action, like ptyalin, must be confined to the early period of digestion before the contents of the stomach have reached their normal activity.” ( Italics mine.)
Oxalic acid diluted to 1 part in 10,000 completely arrests the action of ptyalin. There is sufficient acetic acid I one or two teaspoonfuls of vinegar to entirely suspend salivary digestion. The acids of tomatoes, berries, oranges, grapefruits, lemons, limes, pineapples, sour apples, sour grapes, and other sour fruits are sufficient to destroy the ptyalin of saliva and suspend starch digestion. Without, apparently, understanding why, Dr. Percy Howe of Harvard says: “Many people who cannot eat oranges at a meal derive great benefit from eating them fifteen to thirty minutes before the meal.
All physiologists agree that acids, even mild acids, destroy ptyalin, we shall have to continue to insist that acid-starch combinations are indigestible. The blatant assertion by men who never made a serious study of the subject of human nutrition, that any combination of foodstuffs that you like or desire is all right is based on ignorance or prejudice or is just an expression of bigotry.
Our rule, then, should be: eat acids and starches at separate meals.
Chittednen showed that free hydrochloric acid to the extent of only 0.003 per cent is sufficient to suspend the starch-splitting (amylolytic) action of ptyalin, and a slight further increase in acidity not only stops the action, but also destroys the enzyme.In his Textbook of Physiology Howell says of gastric lipase that, “this lipase is readily destroyed by an activity of 0.2 per cent HCI, so that if it is of functional importance in gastric digestion its action, like that of ptyalin, must be confined to the early period of digestion before the contents of the stomach have reached their normal acidity.” We are not here concerned with the destruction of the lipase by the hydrochloric acid of the stomach, but with the destruction of ptyalin by the same acid.
The physiologist Stiles says: “the acid which is highly favorable to gastric digestion, for example, is quite prohibitive to salivary digestion.” He says of pepsin, “the power to digest proteins is manifested only with an acid reaction, and is permanently lost when the mixture is made distinctly alkaline. The conditions which permit peptic digestion to take place are, therefore, precisely those which exclude the action of saliva.” He declares of salivary enzyme, ptyalin, “the enzyme is extremely sensitive to acid. Inasmuch as the gastric juice is decidedly acid it is used to be claimed that salivary digestion could not proceed in the stomach.” Gastric juice destroys, how are we ever to digest our starch foods?
The answer to this question is found in the power of digestive system to adapt its secretion to the digestive requirements of particular foods, providing, of course, that we respect the limitation of their adaptive mechanism. Dr. Richard C. Cabot of Harvard, who was neither advocating nor combating any special method of food combining, wrote: “When we eat carbohydrates the stomach secrets an appropriate juice, a gastric juice of different composition from that which it secrets if it finds proteins coming down. This is a response to the particular demand that is made on the stomach. It is one of the numerous examples of choices or intelligent guidance carried on by parts of the body which are ordinarily thought of as unconscious and having no soul or choice of their own.” Here is the secret: The stomach secretes a different kind of juice when we eat a starch food from what it secrets when we eat a protein food.
Pavlov has shown that each kind of food calls forth a particular activity of the digestive glands; that the power of the juice varies with the quality of the food; that special modification of the activity of the glands are required by different foods; that the strongest juice is poured out when most needed.
When bread is eaten little hydrochloric acid is poured into the stomach. The juice secreted upon bread is almost neutral in reaction. When the starch of the bread is digested, much hydrochloric acid is then poured into the stomach-the digestion of starch and the digestion of protein-do not go on simultaneously with great efficiency. On the contrary, the secretions are nicely and minutely adjusted, both as to character and to timing, to the varying needs of the complex food substance.
Herein lies the answer to those who object to food combining because “nature combines various food substances in the same food.” There is a great difference between the digestion of a food, however complex its composition, and the digestion of a mixture of different foods. To a single article of food that is a starch-protein combination, the body can easily adjust its juice, both as to strength and timing, to the digestive requirements of the food. But when two foods are eaten with different, even opposite digestive needs, this precise adjustment of juices to requirements becomes impossible. If bread and flesh are eaten together, instead of an almost neutral gastric juice being poured into the stomach during the first two hours of digestion, a highly acid juice will be poured out immediately and starch digestion will come to an almost abrupt end.
It should never be lost sight of that physiologically, the first steps in the digestion of starches and proteins take place in opposite media-starch requiring an alkaline medium, protein requiring an acid medium in which to digests. On this point, V. H. Mottram, professor of physiology in the University of London, says in his Physiology that, when the food in the stomach comes in contact with the gastric juice, no salivary digestion is possible. He says: “Now gastric juice digests protein and saliva digests starch. Therefore it is obivious that for efficient digestion the meat (protein) part of a meal instinct is usually the case. Meat preced pudding as being the most economical procedure.”
Mottram explains this matter by saying: “The distal end of the stomach is that in which the churning movement that mixes the food with gastric juice takes place. But the food in the quiescent and is still under the influence of the saliva while the food in the motile end comes in contact with the acid gastric juice and no salivary action is possible.” The simply means that if you eat your protein first and your starch last, that the protein will digest in the lower end of the stomach while the starch will digest in is upper end.
If we assume that there is any line of demarcation between the food in the stomach, as his proposition demands, it is still true that, people in general neither instinctively nor otherwise, consume their proteins and starches in this manner. Perhaps in England it is customary to eat meat at the beginning of a meal and pudding at the end, just we have a similar practice of taking a dessert at the end of a meal in this country, but it is likely to be the practice there as here, to eat starch and protein together. When the average man or woman eat flesh or eggs, or cheese, he or she takes bread with the protein. Hot-dogs, ham sandwiches, hamburgers, toast and eggs, “ham or rye” and similar combination of protein and starch represent the common practice of eating such foods. With such eating, the protein and starch are thoroughly mixed in both ends of the stomach.
Howell makes a somewhat similar statement. He says: “A question of practical importance is as to how far salivary digestion affects the starchy foods under usual circumstances. The chewing process in the mouth thoroughly mixes the food and saliva, or should do so, but the bolus is swallowed much too quickly to enable the enzyme to complete its action. In the stomach the gastric juice is sufficiently acid to destroy the ptyalin, and it was therefore supposed formerly that salivary digestion is promptly arrested on the entrance of food into the stomach, and is normally of but little value of the stomach shows, on the contrary, that some of the food in an ordinary meal may remain in the fundic end of the stomach for an hour or more untouched by the acid secretion. There is every reason to believe, therefore, that salivary digestion may be carried on in the stomach to an important extent.”
It is obivious that salivary digestion may be carried on in the stomach to an important extent only in a small part of the food eaten, providing the eating is the usual haphazard mixtures of bread with meat, bread with eggs, bread with cheese, bread with other protein, or potatoes with protein. When one eats a hamburger or a hot dog, one does not eat his flesh first and then follow with his bun. They are eaten together and thoroughly chewed and mixed together and swallowed together. The stomach has no mechanism for separating these thoroughly intermixed substances and partitioning them off in separate compartments in its activity.
Mixing foods in this manner is not seen in nature-animals tending to eat but one food at a meal. The carnivore certainly does not mix starches with his proteins. Birds tend to consume insect at one period of the day and seeds at another time. This certainly the best plan for man to follow, for, at best, the plan suggested by Mottaram cannot give ideal results.
On the basis of the physiological facts which have been here presented, we offer our second rule for food combining. It is this: Eat protein foods and carbohydrate foods at separate meals.
By this is meant that cereals bread, potatoes and other starch foods, should be eaten separately from flesh, eggs, cheese, nuts and other protein foods.
Two proteins of different character and different composition, and associated with other and different food factors call for different
Modification of the digestive secretions and different timing of the secretions in order to digest them efficiently. For example, the strongest juice is poured out upon milk in the last hour of digestion, upon flesh in first hour. Is there no significance in the timing of the secretions thus seen? In our eating practices we habitually ignore such facts and our physiologists have not attached any importance to such matters. Eggs receive the strongest secretion at a different time to that received by either flesh or milk. It is logical, therefore, to assume that eggs should not be taken with flesh or milk. It is not too late to recall the harm that was done to tubercular patients by feeding them the abominable combination of eggs and milk. It may be noted in passing that for centuries orthodox jews have refrained from taking flesh and milk at the same meal.
The fact is that the digestive process is modified to meet the digestive requirements of each protein food and it is impossible for this to be modified in such a manner as to meet the requirements of two different proteins at the same meal. This may not mean that two different kinds of flesh may not be taken together or that two different kinds of nuts may not be taken at the same time; but it certainly means that such protein combinations as flesh and eggs, flesh and nuts milk and nuts, etc., should not be taken. One protein food at a meal will certainly assure greater efficiency in digestion.
Our rule then, should be: Eat but one concentrated protein food at a meal.
An objection has been offered to this rule that is as follows: the various proteins vary so greatly in their amino-acid content and the body requires adequate quantities of certain of these so that, it is necessary to consume more than one protein in order to assure and adequate supply of amino-acids. But inasmuch as most people eat more than one meal a day and there is a protein in almost every thing we eat, this objection is invalid. One does not have to consume all of his protein at any one meal.
The active work of splitting up (digesting) complex protein substances into simpler substances, which takes place in stomach and which forms the first step in the digestion of proteins, is accomplished by the enzyme, pepsin. Pepsin acts only in an acid medium; its action is stopped by alkali. The gastric juice ranges all the way from nearly neutral to strongly acid, depending upon what kind of food is put into the stomach. When proteins are eaten the gastric juice is acid, for it must furnish a favorable medium for the action of pepsin.
Because pepsin is active in only an acid medium, the mistake has been made of assuming that the taking of acids with the meal will assist in the digestion of protein. Actually on the contrary these acids inhibit the outpouring of gastric juice and thus interfere with the digestion of proteins. Drug acids and fruit acids demoralizes gastric digestion, either by destroying the pepsin or by inhibiting its secretion. Gastric juice is not poured out in the presence of acid in the mouth and stomach. The renowned Russian physiologist, Pavlov, positively demonstrated the demoralizing influence of acids upon digestion-both fruit acids and the acid-end results of fermentation. Acid fruits by inhibiting the flow of gastric juice-an unhampered flow of which is imperatively demanded by protein digestion-seriously handicaps protein digestion and results in putrefaction.
The normal secrets all the acid required by pepsin in digesting a reasonable quantity of protein. An abnormal stomach may secret too much acid (hyperacidity) or an insufficient amount and digestion. While pepsin is not active except in the presence of hydrochloric acid (I can find no evidence that other acids activate this enzyme), excessive gastric acidity prevents its action. Excess acid destroys the pepsin.
Based on these simple facts of the physiology of digestion, our rule should be: Eat proteins and acids at separate meal.
When we consider the actual process of protein digestion in the stomach and the positive inhibiting effects of acids upon gastric secretion, we realize at once the fallacy of consuming pineappe juice or grapefruit juice or tomato juice with meat, as advocated by certain so-called dietitians, and the fallacy of beating up eggs in orange juice to make the so-called “pep-cocktail”, advocated by other pseudo-dietitians.
Lemon juice, vinegar or other acid used on salads, or added to salad dressing, and eaten with a protein meal, serve as a severe check to hydrochloric secretion and thus interfere with protein digestion.
Although nuts or cheese with acid fruits do not constitute ideal combinations, we may make exception to the forgoing rule in the case of these two article food. Nuts and cheese containing as they do considerable oil and fat (cream), are about the only exceptions to the rule that when they are not immediately digested. Furthermore acids, do not delay the digestion of nuts and cheese; because these foods contain enough fat to inhibit gastric secretion for a longer time than do acids.
Mcleod’s Physiology in Modern Medicine says: “Fat has been shown to exert a distinct inhibiting influence on the secretion of gastric juice… the presence of oil in the stomach delays the secretion of juice poured out on a subsequent meal of otherwise readily digestible food .” Here is an important physiological truth, the full significance of which ha seldom been realized. Most men and women who write on food combining ignore depressing effect fat has upon gastric secretion.
The presence of fat in the food lessens the stomach of appetite secretion that is poured into the stomach, lessens the amount of “Chemical secretion” poured out, lessens the activity of of gastric glands, lower the amount of pepsin and hydrochloric acid in the gastric juice and may lower gastric tone by as much as fifty per cent. This inhibiting effect may last two or more hours.
This mean that when protein food is eaten, fat should not be taken at the same meal. In other words such food as cream, butter, oils of various kinds, fat meats, etc., should not be consumed at the same meal with nuts, cheese eggs, flesh. It will be noted, in this connection, that those foods that normally contain fat within themselves, as nuts or cheese or milk, require longer time to digest than those protein that are lacking in fat.
Our fourth rule, then, is: Eat fats and proteins at separate meals:
It is well to know that an abundance of green vegetables, especially uncooked ones, counteract the inhibiting effect of fact, so that is one must have fat with one’s protein, one may offset its inhibiting effect upon the digestion of protein by consuming much green substances with the meal.
All sugars-commercial sugars, syrups, sweet fruits, honey, etc.-have an inhibiting effect upon the secretion of gastric and upon the motility of the stomach. This fact adds significance to the remark made to children by mothers that the eating of cookies before meals “spoil the appetite.” Sugars taken with proteins hinder protein digestion.
Sugars undergo no digestion in the mouth and stomach. They are digested in intestine. If taken alone they are not held in the stomach long, but are quickly sent into the intestine. When eaten with other foods, either proteins or starches, they are held up in the stomach for a prolonged period, awaiting the digestion of the other foods. While thus awaiting the completion of protein of starch digestion they undergo fermentation.
Based on these simple facts of digestion, our rule is: “Eat sugars and protein at separate meals”
Starch digestion normally begins in the mouth and continues, under proper conditions, for some time in the stomach. Sugar do not undergo any digestion in either mouth or stomach, but in the small intestine only. When consumed along sugars are quickly sent out of the stomach into the intestine. When consumed with other foods they are held up in the stomach for some time awaiting the digestion of other foods. As they tend to ferment very quickly under the conditions of warmth and moisture existing in the stomach, this type of eating almost guarantees acid fermentation.
Jellies, jams, fruit butters, commercial sugar (white or brown, beet, cane or latic), honey, molasses, syrups, etc., added to cakes, breads, pastries, cereals, potatoes, etc., produce fermentation. The regularity with which millions of our people eat cereals and sugar for breakfast and suffer with sour stomach, sour eructations, and other evidences of indigestion as a consequence, would be assuming were it not so tragic. Sweet fruits with starch also result in fermentation. Breads containing dates, raisins, figs, etc., so popular among the frequenters of the “health foods” stores, are dietetic abominations. In many quarters it is thought that if honey is used instead of sugar this may be avoided, but such is not the case. Honey with hot cakes, syrup with hot cakes, etc., are almost sure to ferment.
There is every reason to believe that the presence of sugar with the starch definitely interferes with digestion of starch. When sugar is taken into the mouth there is copious outpouring of saliva, but it contains no ptyalin for ptyalin does not act upon sugar. If the starch is disguised with sugar, honey syrup, jellies, jams, etc., this will prevent the adaptation of the saliva to starch digestion. Little or no ptyalin will be secreted and starch digestion will not take place.
Major Reginald F. E. Austin, M. D., R.A.M.C., M.R.C.S., L.R.C.P., says: “foods that are wholesome by themselves or in certain combinations often disagree when eaten with others. For example, bread and butter taken together cause no unpleasantness, but if sugar or jam marmalade is added trouble may follow. Because the sugar will be taken up first, and the conversion of the starch into sugar is then delayed. Mixtures of starch and sugar invite fermentation and is attendant evils.”
Upon these facts we base the rule: “Eat starches and sugars at separate meal.”