Owing to certain peculiarities in our anatomical construction we are not intended by Nature to be vegetarians. This is amply demonstrated when we consider the formation of our teeth. These are neither the teeth of carnivorous nor of herbivorous animals. We have, in fact, teeth similar to those found among omnivorous animals, such as the dog and pig, while our whole metabolism, the transformation and assimilation of food in our bodies, presents great similarity to that of the dog.
The construction of our intestines is further evidence that Nature did not intend us to be numbered among the herbivorous animals, which are required to have an enormously long intestine to store up and assimilate the very large quantity of herbs or vegetables which are necessary to satisfy their wants. We should have to possess an intestine many times longer than we are provided with in order to be able to exist on vegetables alone; and even with such an intestine it would be very difficult for us to live comfortably for a long period on a purely vegetarian diet. It is, however, certainly possible to exist on such a diet for a certain time; and it may be of direct advantage for those persons who have overtaxed their digestive organs by large quantities of meat food, as it will afford the said organs a well merited rest. In order to live for a long period without risk on a vegetarian diet, it is necessary to add certain products of animal sources, such as milk and eggs. We know from personal experience that with a vegetarian diet supplemented by cereals, especially rice, milk, butter, and eggs, it is possible to exist very comfortably for a long time, and to thrive on it, for we have frequently witnessed a considerable increase in the weight of the body. This experience we have also gained and confirmed by personal test.
A vegetarian diet, when supplemented by milk and butter, can be indulged in for a considerable time, and advantage may be gained therefrom. In many cases of nervous diseases it is of excellent value, especially in neurasthenia and hysteria, Graves’s disease, myxœdema, etc., when meat food is deleterious, for reasons we have often given. With such a diet we can also avoid all the dangers which threaten us from the formation of uric acid. We must, however, avoid taking in large quantities of such vegetables as beans, peas, etc., which, according to Walker Hall, contain purin bodies, the mother substances of uric acid.
Rice is the vegetable which will form the least uric acid, and it is at the same time one of the most nourishing of vegetarian foods, as it contains 77 per cent. of carbohydrates.
Thus with vegetarian diet we can avoid, in great probability, those diseases which arise from an excessive formation of uric acid. As Professor Dettweiler,[273] of Freiburg, demonstrated at the German Congress of Medicine in 1907, the viscosity of blood is greatly diminished by a vegetarian diet. As gout is a disease which is due, in all probability, to a retention of uric acid (after preliminary changes in the thyroid and kidneys, as we have pointed out in a communication to the Paris Biological Society, February 25, 1907), a long extended vegetarian diet can unquestionably be of a great benefit for the prevention and treatment of this disease. It is, however, necessary that such a diet should be prescribed for a very long time (for several months at least) if we desire to reap the full benefit from it.
To prevent the development of diabetes, also, especially in cases of children of diabetic parents, a vegetarian diet can be of great use. In the chapter on the deleterious action of excessive meat food, we refer in detail to the fact that diabetes is most often found in persons addicted to much meat food, especially if carbohydrates are taken in large quantities at the same time. Obesity is seldom found in persons who live on a vegetarian diet. Carbohydrates can be taken in large quantities without producing obesity, if only meat is not taken at the same time in more than a limited amount.
Arteriosclerosis is very seldom found in persons who have been addicted for many years to vegetarianism. Not only is this due to the fact that a vegetarian diet is the least deleterious to the circulatory system, but as we have mentioned above, the viscosity of the blood is also diminished; but with a vegetarian diet, coupled with milk, there is much less intestinal putrefaction, if any, than with a meat diet. It is well known that the production of arterial sclerosis can be facilitated by the products of intestinal putrefaction.
As Brissaud and Siccard have shown, the injection of adrenalin and uric acid at the same time into animals produces atheromatosis in each case. We also know, from clinical observation generally, that arteriosclerosis is of greater frequency among gouty people, and the frequency of diabetes among such can be attributed to arteriosclerotic changes in the pancreas (endarteritis obliterans, Flexner).
Marcel Labbé has shown at the French Congress of Internal Medicine in Paris, 1907, that a diet of cereals, milk, butter, and sugar diminishes the quantity of uric acid, while the addition of nucleo-albumins augments it.
Vegetarian diet is of great service to the intestines, their torpidity being thereby greatly overcome; and if milk be taken at the same time intestinal putrefaction is checked and the tendency to catarrh improved. Such a diet is also of great value to other important organs: the thyroid, liver, and kidneys; as in cases where such are in a diseased condition, the chances of recovery or for a more prolonged life are much enhanced, because such a diet is least harmful to these organs.
But the greatest advantages of a vegetarian diet are seen in the prevention of the ravages of old age by this means. By the use of such a diet we can, to a certain extent, check the degeneration of those organs which play the most important pathological roll in the development of old age, and which have already been mentioned several times, viz.: the thyroid, liver, and kidneys (see the hygiene of these organs). The degeneration of these may produce the retention of toxic products and a condition of auto-intoxication; but by a vegetarian diet, coupled with milk, these troubles may be more easily avoided.
A vegetarian diet, with milk and a few eggs daily, is the best nourishment for old people; the greater the age the more of the latter should be taken. In fact, persons advanced in age will do well to eat very little meat, for reasons which are fully given in the chapter on the dangers of a too abundant meat diet.
We have thus seen that a vegetarian diet can give the best results, not only in the prevention and cure of many diseases, but also in the preservation of health in old age. It is a fact that we often see persons who follow such a diet looking much fresher and more youthful than those who partake of much meat, especially when they have passed the seventies.
But if milk and vegetarian diet, with a few eggs daily, can be taken for many years and yield good results, it is quite a different case with those people who are in the habit of living only on vegetables to the exclusion of any article of animal food; such are vegetarian fanatics, and if they keep up this deleterious habit for a lengthened period, they must inevitably suffer for it.
Even if we do not admit the pretensions of certain authors, who declare that the albumin of the vegetable is less nourishing than the albumin of animals, still it is impossible for us to introduce into our bodies the quantity of vegetables which would contain the number of calories necessary in order that we should not suffer from a deficiency of them, and at the same time would allow for waste. To satisfy the requirements of our bodies we would have to eat enormous quantities of vegetables and thus overload the stomach and intestines, with the result that even the strongest stomach would undoubtedly give way after a certain time, and dyspepsia, especially sour stomach, and eventually atony, and in many cases even dilatation, of the stomach would follow; and abnormal fermentation would readily take place in the intestines after a certain time. Consider, also, what large amounts of enzymes, how much saliva, hydrochloric acid, bile, etc., must be produced in order to insure a good digestion and assimilation of the food, though it is of course true that the ferments, at least, can readily act in a very small degree upon large quantities of food. Vegetarian diet has also the drawback that, for reasons already mentioned, more salt must be taken when we partake of it.
There are many people who develop hyperchlorhydria after a vegetarian diet, and we frequently had to have our patients abandon such a diet when they got acid stomachs; and they only recovered from these ill effects after animal food had been given in certain quantities. It is certain that the present capacity of the stomach and intestines, and their present anatomical and histological structure, also, is not sufficient or adequate for the continued use of a vegetarian diet, the greatest danger of which lies, however, in the threatening under-nutrition, and in consequence the imminent danger of bacterial infection.
It is a positive pathological fact that under-nutrition (or defective nutrition) through lack of the necessary amount of proteids in the diet exposes one more to infection by bacilli. This is plainly to be seen every day, especially in regard to tuberculosis; and as the best preventive to this we strongly recommend plenty of nutrition, especially rare meat and milk. We have personal knowledge of several cases of tuberculosis arising from a purely vegetarian diet (see, also, Chapter III). The findings of Grawitz[274] indicate that an insufficient proteid diet predisposes also to anæmia. The importance of this fact is emphasized by Sajous who has shown (1903) that defective nutrition weakens the activity of the pituitary, thyroid and adrenals, the products or secretions of which take an active part in the destruction of bacteria and their toxins.
In our chapter on the destruction of toxic products by the liver, we referred to evidence gained from actual experiments, that under-nutrition predisposes to infection. We have referred to Roger and Garnier, who have proved that the liver loses its antitoxic properties in cases of under-nutrition, and it is probable that the other antitoxic organs exhibit a similar condition.
There are two primary conditions on which infection depends: 1. The invasion of the microbes. The greater their number and virulence the more easily will infection take place. 2. The diminution of our normal resistance against infection, which, as we have seen in the third chapter, can be caused by different factors, among which is under-nutrition.
In any case we are surrounded by countless millions of microbes every day, which are only too anxiously awaiting a favorable moment to attack us; and should we be so foolish as to encourage their attacks by adopting fads in our nourishment?
The greatest danger of a strictly vegetarian diet is for those persons whose parents suffered from chronic cachectic diseases, such as tuberculosis, chronic alcoholism, etc., in whose cases the perils of infection are much more menacing. Should such expose themselves still more by insufficient nourishment, such a course can be called by no other name than culpable negligence, leading to suicide. It is the object of this book to demonstrate the best way to reach a ripe old age and to avoid disease; it is, therefore, my duty to emphasize the dangers of a sole vegetarian diet, especially for weak people.
As the processes of oxidation are, as a rule, diminished in old age, especially in its advanced stage, such persons can exist on less food and need not introduce so many calories into their system; and as they also take less exercise, so they require less nourishment. Consequently, they can live better on a vegetarian diet than can the young and robust. Even then, however, it may be prejudicial to their health to live solely on vegetables, and it will be necessary to supplement this with milk and a few eggs daily. For young people such a diet, continued for a prolonged period, will present evils, and it would therefore be advisable not to continue such nourishment longer than four or six weeks, and then add meat once a day to the former diet of vegetables. This is mixed vegetarian diet, and should be interposed in the ordinary diet routine at intervals and at times of necessity. Thus when symptoms of over-nutrition may present themselves a purely vegetarian regimen may be followed, but not for longer than three or four weeks; but for those having a weak constitution and great tendency to infection, a purely vegetarian diet is not indicated, even for so short a time as a week.
Judging from my own personal experience, I do not think it possible for persons who confine themselves solely to a vegetable diet to prosper and look well, especially if they exist on such insufficient food for several months, and still less so if they continue such a course for a longer time. We know that all the people of our acquaintance who existed for a long time on such a diet, presented a pale, haggard and miserable appearance, so that we could not but pity them. We, personally, tried to follow their example, but after a short experience hunger forced us to abandon the idea. Even long and careful mastication did not satisfy our craving for food, so that we had to add milk, cheese, and eggs. We admit, however, that for those of an unhealthy constitution, requiring less food, and especially for those who are in the habit of overeating,[275] there may be found some satisfaction in such a system of under-nutrition; but even they have no right to call it a healthy method of nourishment. We have found, that as a whole, women can stand more easily, and also for a longer time, a vegetarian diet.
Those who point out by historical facts that man was destined to vegetarian diet may not be right, for it is certain that many thousands of years ago man was a fruit eater, when he also lived in trees. When he began to reside on terra firma, compelled to so do by the scarcity of fruit in consequence of the increase of humanity, he turned hunter and meat eater. When we visit ethnographical museums, we find that from 10 to 5000 years before Christ man fashioned spear heads and knives from flint, with which he killed animals, upon the meat of which he subsisted; and at such times he lived chiefly on meat and fish, only later becoming agriculturist and omnivorous in diet.
Many believers in a sole vegetarian diet like to point to animals as an example, for these, they maintain, prosper on, and are contented with herbs. Let us follow up this statement and see what we find to be the case in the animal world.
We maintain that the truth of the matter is that there are few animals of the nobler kind to be found among those existing on herbs. We find the monarchs of the animals among the carnivorous class, and if we take them as our example, the courage and valor of the lion will appeal to us far more forcibly than the cowardice and helplessness of the sheep.
Energy gained by the addition of a certain amount of animal food does not exclude the nobler qualities peculiar to the human brain, freed from fads and fanaticism, and it is a valuable factor in combating the numerous vicissitudes of life.