Part 2 (1/2)
In the present state of society, when really good vegetarian fare is difficult to procure away from home, eggs, cheese, and milk are a great convenience.
Digestion.--The digestive juices contain certain unorganised ferments, which produce chemical changes in the food. If the food is solid, it has to be liquefied. Even if already liquid it has generally to undergo a chemical change before being fitted for absorption into the body. The alimentary ca.n.a.l is a tubular pa.s.sage which is first expanded into the mouth, and later into the stomach. As the food pa.s.ses down, it is acted upon by several digestive juices, and in the small intestine the nutritive matter is absorbed, whilst the residue pa.s.ses away.
The saliva is the first digestive juice. It is alkaline and contains a ferment called ptyalin. This acts energetically on the cooked and gelatinous starch, and slowly on the raw starch. Starch is quite insoluble in water, but the first product of salivary digestion is a less complex substance called soluble-starch. When time is allowed for the action to be completed, the starch is converted into one of the sugars called maltose.
In infants this property of acting on starch does not appear in effective degree until the sixth or seventh month, and starch should not be given before that time. Only a small quant.i.ty should be provided before the twelfth month, when it may be gradually increased. Dr. Sims Wallace has suggested that the eruption of the lower incisors from the seventh to the eighth month, was for the purpose of enabling the infant--in the pre-cooking stage of man's existence--to pierce the outer covering of fruits so as to permit his extracting the soluble contents by suction; and accordingly when these teeth are cut we may allow the child to bite at such vegetable substances as apples, oranges, and sugar cane. Dr. Harry Campbell says that starch should be given to the young, ”not as is the custom, as liquid or pap, but in a form compelling vigorous mastication, for it is certain that early man, from the time he emerged from the ape till he discovered how to cook his vegetable food, obtained practically all his starch in such a form. If it is given as liquid or pap it will pa.s.s down as starch into the stomach, to setup disturbance in that organ; while if it is administered in a form which obliges the child to chew it properly, not only will the jaws, the teeth, and the gums obtain the exercise which they crave, and without which they cannot develop normally, but the starch will be thoroughly insalivated that much of it will be converted within the mouth into maltose. Hard well baked crusts const.i.tute a convenient form in which to administer starch to children. A piece of crust may be put in the oven and rebaked, and spread with b.u.t.ter. Later, we may give hard plain biscuits.” Dr. Campbell continues, that he does not say that starch in the pappy form, or as porridge, should find no place whatever in man's dietary at the present day, but we should arrange that a large proportion of our food is in a form inviting mastication.
The teeth perform the very important function of breaking down our food and enabling it to be intimately incorporated with the saliva and afterwards with the digestive juices. The Anglo-Saxon race shows a greater tendency to degeneracy in the teeth than do other races; the teeth of the present generation are less perfect than those of previous generations. A dentist writes (_Lancet_, 1903-2, p. 1054) ”I have had the opportunity of examining the teeth of many natives in their more or less uncivilised state, from the Red Indians of North America, the negroes of Africa, to the more civilised Chinese, j.a.panese, and Indians of the East, and I have usually found them possessed of sound teeth, but so soon as they come under the influence of civilised life in Was.h.i.+ngton, Montreal, London, Paris and other cities, their teeth begin to degenerate, though their general health may remain good.” In a long article on mastication in the _Lancet_ (1903-2, p. 84) from which we have already quoted, Dr. Harry Campbell gives as the effect of thorough and efficient mastication, that it increases the amount of alkaline saliva pa.s.sing into the stomach, and prolongs the period of starch digestion within that organ. That it influences the stomach reflexly by promoting the flow of gastric juice.
That the frequent use of the jaws and the tongue, during the period of growth, cause the jaws to expand. If the jaws are not adequately exercised during this period, owing to the use of soft food, they do not reach their normal size, the teeth are overcrowded, do not develop fully, and are p.r.o.ne to decay. The effect of vigorous mastication is to stimulate the circulation in the tooth pulp, which promotes nutrition and maintains a firm dental setting. Dr. Campbell writes: ”I am perfectly at one with Dr.
Wallace, in believing that the removal of the fibrous portion of food is the main cause of the prevalence of caries among moderns.”
When the food reaches the stomach, gastric juice is secreted. This juice contains a ferment called pepsin and hydrochloric acid. Pepsin is only active in an acid media. Starch digestion proceeds in the stomach to such a time--stated as from 15 to 30 minutes--when the acid gastric juice has been poured out in sufficient quant.i.ty to neutralise the alkalinity of the saliva. The gastric juice acts upon the proteids only. After a time the liquefied contents of the stomach are pa.s.sed into the first portion of the small intestine, called the duodenum. Here it meets with the pancreatic juice, which like the gastric juice attacks proteids, but even more energetically, and only in an alkaline media. The proteolitic ferment is called trypsin. The pancreatic, the most important of the digestive fluids, contains other ferments; one called amylopsin, takes up the digestion of any remaining or imperfectly converted starch left from the salivary digestion. Amylopsin is much more powerful and rapid than the ptyalin of the saliva, especially on uncooked starch. Its absence from the pancreatic juice of infants is an indication that starch should not be given them. Another ferment, stearopsin, emulsifies fats. The bile is alkaline and a.s.sists the pancreatic juice in neutralising the acid mixture that leaves the stomach; it also a.s.sists the absorption of fats. The digestion of proteids is not completed in the stomach. There are some who look upon the stomach as chiefly of use as a receptacle for the large ma.s.s of food, which is too quickly eaten to be pa.s.sed at once into the intestines; the food being gradually expelled from the stomach, in such quant.i.ties as the duodenal digestion can adequately treat. A frequently used table, showing the time required for the digestion of various foods in the stomach, is of little practical value. There is ample provision for the digestion of food, there is a duplication of ferments for the proteids and starch. In health, the ferments are not only very active, but are secreted in ample quant.i.ties. The digestive or unorganised ferments must not be confused with the organised ferments such as yeast. The latter are living vegetable cells, capable of indefinite multiplication. The former are soluble bodies, and though capable of transforming or digesting some thousands of times their ma.s.s of food, their power in this direction is restricted within definite limits. Another and preferable name for them is enzymes.
The action of saliva on starch is powerfully r.e.t.a.r.ded by tea, this is due to the tannin. Coffee and cocoa are without effect. Tea infused for two minutes only, was not found to have sensibly less restraining effect than when infused for thirty minutes. On peptic digestion both tea and coffee had a powerful r.e.t.a.r.ding effect. When of equal strength cocoa was nearly as bad, but as it is usually taken much weaker, its inhibitory effect is of little consequence.
Bacteria are minute vegetable organisms, which exist in the dust of the air, in water and almost everywhere on or near the surface of the earth.
They are consequently taken in with our food. They exist in the mouth; those in carious teeth are often sufficient to injuriously affect digestion and health. The healthy gastric juice is to a great degree antiseptic, but few bacteria being able to endure its acidity. When the residue of the food reaches the large intestine, bacteria are found in very great numbers. The warmth of the body is highly favourable to their growth. They cause the food and intestinal _debris_ to a.s.sume its faecal character. Should the ma.s.s be retained, the bacterial poisons acc.u.mutate and being absorbed into the body produce headaches, exhaustion, neurasthenia and other complaints. Proteid matter, the products of its decomposition and nitrogenous matter generally, are especially the food of bacteria; this is shown in the offensiveness of the faeces of the carnivora, notwithstanding their short intestines, compared with that of the herbivora. Also in the difference of the faeces of the dog when fed on flesh and on a nearly vegetable diet. On a rich proteid diet, especially if it consists largely of flesh, the bacterial products in the intestines are greater than on a vegetable diet. On the latter such a disease as appendicitis is rare. Professor Elie Metchnikoff, of the Pasteur Inst.i.tute, thinks that man's voluminous and highly developed large intestine fulfils no useful purpose, and on account of its breeding a very copious and varied bacterial flora, could with advantage be dispensed with. He also has said that man, who could support himself on food easily digestible, has a small intestine which is disproportionately fully developed. Instead of having between 18 and 21 feet of small intestine, man might do with one-third of that length. According to him, there is a disharmony of our food and our digestive system. Referring to such views, and the desire of some surgeons to remove the vermiform appendix and portions of the intestines upon too little provocation, Sir W. Macewin, M.D., F.R.S. (_B. Medical Jrn._, 1904, 2 p. 874) says:--”Is this human body of ours so badly constructed that it contains so many useless parts and requires so much tinkering? Possibly I may be out of fas.h.i.+on with the times, as I cannot find such imperfections in the normal human body as are alleged. On the contrary, the more one looks into the human body and sees it work, the better one understands it and the more one is struck with the wondrous utility, beauty, and harmony of all its parts.” Our food we can change, but not our organs-except by a dangerous surgical operations. Our teeth with our complex and very long intestines are adapted for fibrous, bulky and solid food. On such food mankind has lived for an immense period of time. It is true that there are several theoretical advantages in cooked vegetable foods; but unfortunately there is a want of conformity with our digestive organs. If a flesh diet is taken, the incongruity is greater. Concentrated food causes constipation. An active man, leading an out-of-door life, can take unsuitable food with little or no apparent inconvenience, the movements of his body favouring intestinal action; whilst the same food to a sedentary person will prove distinctly injurious.
Some persons have such a vigorous digestion that they can consume almost any food, even that which is obviously unsuitable; not only bad in kind but excessive in quant.i.ty. Other persons have to be very careful. Many have boasted that they can take of what they call the good things of life to their full, without bad effect. We know of such men who have been much esteemed for their joviality and good nature, but who have broken down in what should have been a hearty and useful middle life. There are others who were poorly equipped for the battle of life, with indifferent const.i.tutions, never having had the buoyancy and overflowing of animal spirits; but who, by conserving such strength as they had, have outlived all their more healthy but less careful comrades. The errors of the parents are often most evident in the children or grandchildren. There are many persons who cannot eat of some particular food, although it may be quite wholesome to others. Sometimes it is a psychological rather than a physiological disability, which may he overcome by an effort of the will. At other times it seems to have no connection with the imagination, although it is not always possible to give a sound reason for it. In the main, of course, there are principles of dietetics applicable to all alike, but in regard to details, everyone should make rules for himself, according to his experience. When there appears no real reason for an idiosyncrasy, a little humouring of our taste and digestion will often overcome it, to our advantage. It is generally those of delicate const.i.tution who are most sensitive. Some cannot eat oatmeal except in small quant.i.ty. Olive and other vegetable oils, even when of good quality cannot be taken by many people, whilst others find them quite as wholesome, or even better than b.u.t.ter. Vegetarians can generally detect lard in pastry both by its taste and its after effects, although those accustomed to this fat do not object to it. It is also surprising how some individual's tastes and habits will vary at different periods of their lives.
One form of dyspepsia is due to undigested starch remaining in the stomach and causing an excessive secretion of hydrochloric acid. As long as proteid food is present, the pepsin and acid expend themselves on it, and are removed together. The undigested starch continues to stimulate gastric secretion, and the acid residuum causes pain, heartburn and flatulence. If there be also any butyric acid, or some other fatty acid, derived from milk, b.u.t.ter, cheese, &c., there will be acid eructations. For this form of indigestion there are several methods of treatment. First; the very thorough cooking of all starchy food, and it is an advantage to take a little good extract of malt, either at the time of eating or directly afterwards. The diastase of the malt has the same action on starch as the ptyalin in the saliva. It is better, scientifically, to have the farinaceous food at about 130 F. (as hot as the mouth can bear will do), and then to add malt extract. On keeping the mixture warm, from a few minutes to half an hour or more, the starch is digested and rendered soluble. Such food is not very pleasant to take. The food known as Grape Nuts has been treated in a similar manner. The use of malt extract, however, seems a clumsy subst.i.tute for salivary digestion. Second; the eating of starch in the form of hard and dry biscuits, crusts and other hard food, which demand thorough mastication and insalivation, and the keeping in the mouth for a long while, during which the saliva has time to act. This is the best plan. Third; the taking of sodium bicarbonate towards the end of the period of digestion, in order to neutralise the acid in the stomach. This gives relief, but does not cure, as the dose has to be repeated after each meal; in course of time the quant.i.ty of soda has sometimes to be increased to an alarming extent. Fourth; the abstention from starchy foods and the subst.i.tution of an exclusive flesh dietary. In the ”Salisbury” treatment, raw minced beef is given. This method often gives immediate relief, but its ultimate effect on the kidneys and other organs is very bad.
No hard and fast rule can be laid down as to the number of meals into which the daily amount of food required should be divided. The stomach appears to work to the best advantage when it is full, or nearly so, and the appet.i.te is appeased. Three approximately equal meals seems to be a convenient division. Dr. Dewey and his followers advise only two meals a day, and it seems incontestable that many persons find the plan advantageous. These are generally adults with weak digestions, or elderly persons who, on account of their age and the sluggish action of their a.s.similative functions, require comparatively little food. Children, on account of their vigorous vitality, rapid growth and hearty appet.i.tes, ought not to be restricted to this number. Persons who have got into the pernicious habit of greatly over-eating, and whose stomachs have become distended and unusually large, sometimes find it easier to restrict their daily food to a healthy quant.i.ty by taking only two meals. The general objections against two meals are that either two little food is taken, or the ingestion of such a large quant.i.ty is bad for the stomach and causes it to press on the adjacent viscera. The large quant.i.ty of blood and nerve force drawn to the over-distended stomach, depletes the brain and nervous system, causing drowsiness and incapacity for mental and physical work.
The carnivora, whose opportunity for obtaining food--unlike the herbivora--is irregular and often at long intervals, gorge themselves upon opportunity and are in the habit of sleeping after a meal. The frugivora and herbivora, however, are alert and ready to fly from their enemies should such appear. The conveying of so much nourishment to the liver and blood stream at one time, is probably a greater tax on them. A light lunch between the usual full meals has nothing to recommend it. The stomach is burdened to little purpose, often before it has finished with one meal another is imposed upon it, no time being left for recuperation.
Dietaries.--The best proportions of proteids, carbo-hydrates and fats required for the nourishment of the body has not yet been conclusively decided. The common plan is to average the dietary of large bodies of persons, particualrly of soldiers and prisoners. These dietaries have been adjusted empirically (the earlier ones at least), and are generally considered as satisfactory. They are chiefly of English and German origin.
Another method is to laboriously a.n.a.lyse the injesta or food consumed and compare it with the dejecta or excretions, until a quant.i.ty and kind of food is found which is just sufficient to keep the body in equilibrium.
This latter plan is the best, but to be quite satisfactory must be tried on a large number of suitable persons under varying conditions, both of quant.i.ty and kind of food. Nearly all the experiments have been made on persons accustomed to a stimulating dietary: their usual food has included a considerable quant.i.ty of flesh and alcoholic drinks. Sufficient attention has not been paid to the dietaries of the more abstemious races who partake of little if any flesh food. The standard daily dietary for a man of average weight, doing a moderate amount of work, is variously stated by the best authorities as proteids from 100 to 130 grammes, fat 35 to 125 grammes, and carbo-hydrates 450 to 550 grammes. There is a surprising difference of opinion on the amount of fat, but those who give least fat give the largest quant.i.ty of carbo-hydrate and _vice-versa_. Dr.
R. Hutchison in ”Food and Dietetics,” sums up the quant.i.ties given by the highest authorities as follows:---
Proteid 125 g. ( 4.4 oz.) x 4.1 = 512 cal. = 20 g. N, 62 C Carbo-hydrate 500 g. (17.6 oz.) 4.1 2050 200 Fat 50 g. ( 1.8 oz.) 9.3 465 38 ----------------- ---- -------- ----- 675 g.(23.8 ) 3027 Total 20 g. N, 300 C
The nutrient ratio is 1 : 4.9. For scientific purposes, metrical weights and measures are used, instead of the inconvenient English grains, ounces, pounds, &c. (1 gramme = 15.43 grains; 1 ounce avoirdupois = 437.5 grains = 28.35 grammes). A calorie is a measure of the power of a food in generating heat and muscular energy (these two being convertible).
The calories used in food tables are kilo-calories, representing the amount of heat which would raise a kilogramme (1000 grammes) of water 1 Centigrade. This is the same as raising 1 pound weight 4 Fahrenheit.
According to the table given, 125 grammes of dry proteid are required per day; this contains 20 grammes of nitrogen and 62 of carbon. When thoroughly consumed or utilised in the body, the heat or its equivalent in muscular work equals 512 kilo-calories. Proteids have, of course, an additional value as tissue formers. The factors used here, of 4.1 and 9.3, are those commonly employed; but the latest and most reliable research, taking account only of that part of the food which is actually available in the body, gives for proteid and carbo-hydrate 4 calories, and for fat 8.9 calories.
Fat has a higher food value than the carbo-hydrates, as 4.1 : 9.3 = 2.27 or 4.0 : 89 = 2.225, according to whether the old or new factors are used.
In the table of a.n.a.lyses 2.225 was used. The standard dietary for a woman, or of a boy 14 to 16 years of age, is given as equivalent to eight-tenths that of a man; a child of 10 to 13 six-tenths; of 2 to 5 four-tenths. A man doing hard work requires one-tenth more. The following table gives three standard dietaries, and a few actual ones, in grammes per day. The food of persons in easy circ.u.mstances, and of working men in the receipt of good wages, approximate to the standard dietaries, except that the fat is higher and the carbo-hydrates proportionately less. This is due to an abundance of animal food. It was thought unnecessary to give them in detail:--
Pr't. Fat. C'rb. Cal. N.R.
Hutchison: Man, moderate muscular work 125 50 500 3027 4.9 At.w.a.ter: ” ” ” ” 125 ... ... 3400 6.2 Voit: ” ” ” ” 118 56 500 2965 5.5 At.w.a.ter: Woman, light to moderate muscular work, or Man without muscular exercise 90 ... ... 2450 6.1 Football teams, Connecticut and California, U.S. 226 354 634 6590 6.6 Russian peasants 129 33 589 3165 5.4 Negro families--Alabama and Virginia 86 145 440 3395 9.3 Labourers-Lombardy (diet, mostly vegetable) 82 40 362 2192 5.5 j.a.panese, on vegetable diet (_a_) 71 12 396 2026 6.0 Trappist monk, in Cloisters-vegetable diet 68 11 469 2304 7.3 Java village--Columbia Exposition, 1893 66 19 254 1450 4.7 Sewing girl-London (3/9 per week) 53 33 316 1820 7.3 German vegetarians 54 22 573 2775 11.6 German labourers' family (poor circ.u.mstances) 52 32 287 1640 7.2 Dr. T.R.A.--wheatmeal bread and water only (_b_) 82 8.5 470 2342 6.0 Man--3 years' exclusively vegetable diet (_c_) 54 22 557 2710 11.2 Thomas Wood, the miller of Billericay (_d_) 55 5.7 313 1560 6.0
Dr. Alexander Haig considers that 88 grammes of proteid is required by a man leading a decidedly active life.
NOTES.--(_a_) The j.a.panese are of small stature and weight.
(_b_) One of a series of experiments by A.W. Blyth, 1888. 1-1/2 lbs. of wheatmeal per day was required for equilibrium; sedentary occupation, with a daily walk of six miles.
(_c_) See ”A Text Book of Physiology,” by M. Foster, 5th edition, part ii., p. 839; the diet was bread, fruit and oil. The man was in apparently good health and stationary weight; only 59 per cent. of the proteids were digested, leaving the small quant.i.ty of 32 grammes available for real use.
In commenting upon this, Professor Foster writes:--”We cannot authoritatively say that such a reduction is necessarily an evil; for our knowledge will not at present permit us to make an authoritative exact statement as to the extent to which the proteid may be reduced without disadvantage to the body, when accompanied by adequate provision of the other elements of food; and this statement holds good whether the body be undertaking a small or large amount of labour.”
(_d_) The Miller of Billericay's case is quoted by Dr. Carpenter, and also by Dr. Pavy. It was reported to the College of Physicians in 1767 by Sir George Baker. A remarkable degree of vigour is said to have been sustained for upwards of eighteen years on no other nutriment than 16 oz. of flour, made into a pudding with water, no other liquid of any kind being taken.