“In the digestion of proteid food-stuffs by the combined action of gastric and pancreatic juice in the alimentary tract, a large proportion of the proteid is destined to undergo complete conversion into amino-acids; and, from these fragments, the body, by a process of synthesis, can construct its own peculiar type of proteid. This latter suggestion is worthy of a moment’s further consideration; as is well known, every species of animal has its own peculiar type of proteid, adapted to its particular needs. The proteids of one species directly injected into the blood of another species are incapable of serving as nutriment to the body, and frequently act as poison.... The availability or digestibility of food can be determined only by physiological experiment. By making a comparison, for a definite period of time, of the amount of the different food ingredients, and the amount that passes unchanged through the intestines, an estimate of its digestibility can be made.... In a general way it may be stated that with animal foods, such as meats, eggs, and milk, about 97 per cent. of the contained proteid is digested, and thereby rendered available to the body. With ordinary vegetables, on the other hand, as they are usually prepared for consumption, only about 85 per cent. of the proteid is made available. With a mixed diet, with a variable admixture of animal and vegetable foods, it is usually considered that about 92 per cent. of the proteid contained therein will undergo digestion.”
At first sight, it would appear that this runs counter to the argument that has been advanced; but we must take into account the fact that Professor Chittenden is here speaking only of vegetable proteid, and has made no mention of nuts; and, as we have seen from the tables, nuts contain a far larger percentage of protein than meats. When we take into consideration the small disproportion in the percentage assimilated, and find that when meat is mixed with other articles of food, as it invariably is, the percentage of its availability is reduced to 92 per cent., while vegetable foods are proportionately raised to the same figure, we see that the apparent discrepancy practically vanishes to nothing. And when we further take into account the fact that an equal amount of proteid can be obtained from a far less quantity of non-flesh food, we see that, from an equal bulk of food material, a far larger proportionate percentage would be assimilated from the vegetable foods than from the animal.
Another great argument which has always been advanced in favour of meat-eating, or the ingestion of proteid in the form of animal, as opposed to vegetable food, is that the proteid derived from the animal is far more quickly and readily assimilated by the system than vegetable proteid. The rapidity of the digestion of animal food has always been urged as one of the strongest arguments in its favour, and it is largely for this reason that it has been administered to invalids, and to patients in a depressed and weakened state of body. But now we find that physiological research has completely disproved this old dogma! Professor Chittenden, on p. 30 of his “Nutrition and Man,” says:
“It is evident from what has been stated that the gastric digestion of proteid foods is a comparatively slow process, involving several hours of time; and further, that food material in general remains in the stomach for varying periods, dependent upon its chemical composition.... It is a mistake to assume that the digestion of proteid foods is complete in the stomach. Stomach digestion is to be considered more as a preliminary step, paving the way for further changes to be carried forward by the combined action of intestinal and pancreatic juice in the small intestines.... The importance of gastric digestion is frequently overrated.”
Dr Sylvester Graham, writing on this subject years ago in his “Science of Human Life,” said:
“In vain have they attempted to regulate the diet of man on the chemical principles, and insisted on the necessity for certain chemical properties in the human element to sustain the vital economy. That economy has shown them that it can triumph over the chemical affinities and ordinary laws of organic matter, and bend them to its purposes at pleasure; generating and transmuting from one form to another, with the utmost ease, the substance which human science calls elements; and while the living organs retain their functional power and integrity, elaborating from every kind of element on which an animal can subsist, a chyle so nearly identical in its physical and chemical character, that the most accurate analytical chemists can scarcely detect the least appreciable difference.... Though, while the health and integrity of the assimilating organs are preserved, the physical and chemical character of the chyle are nearly identical, whatever may be the elementary substance from which it was elaborated, yet the vital constitution of the chyle and blood, and consequently of the solids, is greatly affected by the quality of the food. When chyle is taken from the living vessels, the vital constitution of that which is elaborated from flesh meat is capable of resisting the action of bacterial decomposition only a short time, and will begin to putrefy in three or four days at the longest; while the vital constitution of that which is elaborated from pure and proper vegetable elements, will resist this decomposing action for a much larger period, yet it will in the end putrefy with all the phenomena of that formed from flesh meat.”
The bearing of these facts on physical training, the health of the body, and the decomposition of the body after death, need only be pointed out.
It is really extraordinary how writers on dietetics, seem to take a delight, as a rule, in making as many mis-statements and misrepresentations as possible. Take, for example, the following passage in Dr C. S. Read’s Book, “Fads and Feeding”:—
“It is necessary, with the vegetable products, to take the nitrogenous product as Nature gives it to us, which is a drawback; and secondly, vegetable foods are relatively much poorer in this respect than animal foods.... A vegetable diet must needs be bulky, because of its wateriness, especially when cooked, and the large amount of indigestible matter it contains. This tends to abnormally distend the stomach and bowels. The capacity of the stomach becomes greater, more food can be taken, but the distention produces a feeling of satiety before sufficient nourishment has really been ingested. The dealing with such a bulk internally means the expenditure of much nervous energy which might have been better utilised. The wateriness of vegetable foods is extremely disadvantageous, since on absorption it tends to render all the tissues flabby. The individual who leads a sedentary life will feel the disadvantage of vegetarianism more than the active worker.”
Now, not a sentence in the above quotation is correct. If Dr Read had studied vegetarians at first hand, he would have found out his mistakes, and would not have written such rubbish. As a matter of fact, vegetable foods do not supply less nitrogen than meat, but on the contrary more; a vegetable diet need not be bulky, if properly selected—less of it need be eaten than of a mixed diet, because of its greater nutritive value; while the notion that the absorbtion of water from the foods make the tissues “flabby” is, of course, absurd. Altogether, this is almost the greatest string of inaccuracies regarding diet that I have ever come across.
There is one aspect of this question which it might be well to touch upon in this place. The air that we breathe, as we know, contains a large percentage of nitrogen. Might it not be possible for the system to utilise some of this nitrogen, when the body is in a state of nitrogen starvation? Dr De Lacy Evans, surgeon to St Saviour’s Hospital, in London, contended that this might be the case, and in his “How to Prolong Life,” pp. 76-80, wrote:
“It has been argued that fruits will not sustain life, because they do not contain sufficient nitrogen; this argument is founded upon a theory which is demonstrably incorrect, and it is an ascertained fact that fruits alone will support life and good bodily health.... By experiments on ourselves, on friends, and on natives of tropical regions, we find a comparatively small quantity of nitrogen necessary to sustain life; in fact, fruits, taken as a class, contain sufficient nitrogen to sustain human life.... Now fruits will sustain life, and all fruits contain carbon, hydrogen and oxygen, and most of them a small quantity of nitrogen; and if these fruits which will sustain life do not contain sufficient nitrogen, may not man, who breathes and is in contact with an atmosphere (four-fifths of which is nitrogen), by means of his lungs, the surface of which is supposed to be more than twenty times that of the whole body, absorb the necessary nitrogen directly from the atmosphere? From careful observation of the diet of natives in tropical regions, and from direct experiments in England, we may state that this is positively the case. This is often observed in the herbivora: their natural food contains little nitrogen, still it is found in their flesh in about the same ratio as in the carnivora. Further, the carnivora live on food rich in nitrogen—yet one is as well nourished as the other.... Man may live entirely upon fruits, in better health than the majority of mankind now enjoy. Good, sound, ripe fruits are never a cause of disease; but the vegetable acids, as we have before stated, lower the temperature of the body, decrease the process of combustion and oxidation—therefore the waste of the system—less sleep is required, activity is increased, fatigue or thirst hardly experienced: still the body is well nourished, and as a comparatively small quantity of earthy salts are taken into the system, the cause of ‘old age’ is in some degree removed, the effect is delayed, and life is prolonged to a period far beyond our ‘three score years and ten.’”[17]
The consensus of modern opinion, however, seems to be against any such supposition. Chittenden, for example, writes:[18]
“Man lives in an atmosphere of oxygen and nitrogen. He can and does absorb and utilise the free oxygen of the air he breathes; indeed, it is absolutely essential for his existence, but free nitrogen likewise drawn into the lungs at each inspiration is of no avail for the needs of the body.”
As, however, all bodies contain more or less nitrogen in excess, there would be no need to call upon the air for its supply. It would be interesting to note the effects in cases of nitrogen starvation; but the simple fact that animals do die when sufficient nitrogen is subtracted from their food, would seem to indicate that but little nitrogen, if any, can be extracted from the air, even under these circumstances.
After the above lengthy argument, which endeavours to show that sufficient proteid can be supplied the body from vegetable foods, it is somewhat amusing to find that, as a matter of fact, far too much proteid has invariably been eaten by practically all civilised peoples—and that so far from there being any danger of nitrogen starvation, or lack of sufficient proteid, the danger is all the other way, and four-fifths of all the maladies from which mankind suffers are due to the very fact that an excess of proteid has been eaten! All physiologists agree that the majority of people eat far more, not only of proteid, but of all kinds of food, than is required, according to their tables; and Professor Chittenden has recently shown, as the result of an elaborate series of experiments conducted at Yale, that the average proteid standard set by physiologists, as being necessary for the maintenance of health, is at least three times too high! That is, the majority of persons eat considerably more than three times too much proteid! In view of these facts, it is amusing to find so much fear exhibited on all hands in case the proteid supply should not be sufficient in quantity.
These Yale nutrition investigations are now so widely known that it would be useless to do more than refer to them in this place. As the results of experiments upon University professors, upon athletes, and upon a squad chosen from the United States army, it was definitely proved that the proteid standards were far too high: the men flourishing, improving in every direction, and even doing a greater amount of physical work than usual on a diet averaging, in proteid value, about a third said to be necessary by the physiologists. When we take into account the fact that most people eat far more proteid than the physiologists said was necessary, it will be seen at once the tremendous disproportion which exists between the amount actually consumed, and the amount really needed by the body; and how absurd it is, in face of these facts, to persist in demanding an excess of those foods which contain such high proteid percentages! Chittenden says:
“There is no question, in view of our results, that people ordinarily consume much more food than there is any real physiological necessity for, and it is more than probable that this excess of food is in the long run detrimental to health, weakening rather than strengthening the body, and defeating the very objects aimed at.... One-half of the 118 grams of proteid food called for daily, is quite sufficient to meet all the physiological needs of the body, certainly under the ordinary conditions of life; and with most individuals, especially persons not living an active outdoor life, even a smaller amount will suffice.”[19]
The figures and calculations throughout his works, however, show that the proteid intake may be reduced to fully one-third of that said to be necessary in standard physiologies, with nothing but increased health and strength.
In summing up this question of the necessity of meat-eating, one important fact must not be lost sight of, which, in a sense, may be said to settle the argument in favour of the vegetarian dietary without further additional evidence of any kind. It is this: That the bodies of all animals are built from vegetable foods, and consequently, when we eat those animals, we merely eat the vegetable foods, upon which they have subsisted, at second hand! We appropriate or obtain the same chemical elements in organic compound that they originally obtained from their food, but we obtain nothing else. Animals have the power to create nothing. The single fact that all nutritive material is formed by vegetables—animals having the power to appropriate but never to form or create food elements—is proof positive, to my mind, that we can derive all the nutriment we need directly from the vegetable world, and that the best food, and that which is most conducive to man’s highest development—bodily, mentally and spiritually—is found in the use of these vegetables themselves. Those who eat animal food do not get a single element of nutrition, save that which those animals have obtained from vegetables. Hence man, in taking his nutrition indirectly, by the eating of animals, must of necessity get the original nutriment more or less deteriorated from the unhealthy conditions and accidents of the animal he feeds upon—with the impurities and putrescent matters mingled with the blood and in the viscera of animal substances, which are invariably present. Apart from this aspect of the problem—which is one rather of hygiene than of chemistry, and hence will be discussed in the following chapter—it is evident that man can derive no single element of nutrition from the bodies of animals, which he cannot also obtain from suitable vegetable foods. He need not eat grass and herbs, as do the cows and sheep, in order to obtain this material—since chemical analysis of the foods will readily show us that these same elements are contained in fruits, nuts and other substances suited to his economy. This argument alone should, therefore, as a matter of fact, settle the whole case in favour of vegetarianism as against flesh-eating, without any further or additional proof being necessary.