Chapter 4

The action of saliva on starch is powerfully retarded 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 retarding 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 assume its fæcal character. Should the mass be retained, the bacterial poisons accumutate 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 fæces of the carnivora, notwithstanding their short intestines, compared with that of the herbivora. Also in the difference of the fæces 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 Institute, 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 fashion 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 quantity. 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 constitutions, 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 constitution who are most sensitive. Some cannot eat oatmeal except in small quantity. 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 butter. 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, butter, 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 substitute 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 quantity of soda has sometimes to be increased to an alarming extent. Fourth; the abstention from starchy foods and the substitution 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 appetite 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 assimilative functions, require comparatively little food. Children, on account of their vigorous vitality, rapid growth and hearty appetites, 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 quantity 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 quantity is bad for the stomach and causes it to press on the adjacent viscera. The large quantity 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 analyse the injesta or food consumed and compare it with the dejecta or excretions, until a quantity 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 quantity 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 quantity 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 quantity of carbo-hydrate and _vice-versa_. Dr. R. Hutchison in "Food and Dietetics," sums up the quantities 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 analyses 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 circumstances, 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 Atwater: " " " " 125 ... ... 3400 6.2 Voit: " " " " 118 56 500 2965 5.5 Atwater: 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 Japanese, 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 circumstances) 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 Japanese 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 quantity 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.

A striking instance of abstemiousness is that of Cornaro, a Venetian nobleman, who died in the year 1566 at the age of 98. Up to the age of 40 he spent a life of indulgence, eating and drinking to excess. At this time, having been endowed with a feeble constitution, he was suffering from dyspepsia, gout, and an almost continual slow fever, with an intolerable thirst continually hanging upon him. The skill of the best physicians of Italy was unavailing. At length he completely changed his habits of diet, and made a complete recovery. At the age of 83 he wrote a treatise on a "Sure and certain method of attaining a long and healthful life." He says, what with bread, meat, the yolk of an egg and soup, I ate as much as weighed 12 ozs., neither more nor less. I drank 14 oz. of wine. When 78 he was persuaded to increase his food by the addition of 2 oz. per day, and this nearly proved fatal. He writes that, instead of old age being one of weakness, infirmity and misery, I find myself to be in the most pleasant and delightful stage of life. At 83 I am always merry, maintaining a happy peace in my own mind. A sober life has preserved me in that sprightliness of thought and gaiety of humour. My teeth are all as sound as in my youth. He was able to take moderate exercise in riding and walking at that age. He was very passionate and hasty in his youth. He wrote other treatises up to the age of 95.

Kumagara, Lapicque and Breis-acher, have, as the result of their experiments, reduced the quantity of proteid required per 24 hours to 45 grammes. T. Hirschfeld states, as the conclusion of his research, that it is possible for a healthy man (in one case for 15 days and in another for 10 days) to maintain nitrogenous balance on from 30 to 40 grammes of proteid per day. Labbé and Morchoisne (Comptes Rendus, 30th May, 1904, p. 1365) made a dieting experiment during 38 days, upon one of themselves. The proteid was derived exclusively from vegetable food. The food consisted of bread, lentils, haricots, potatoes, carrots, chestnuts, endives, apples, oranges, preserves, sugar, starch, butter, chocolate and wine. At the commencement, the day's food contained 14.1 grammes of nitrogen = 89.3 proteid, which was gradually diminished. On the 7th day 11.6 g. N. = 73.5 g. proteid was reached; during this time less N. was eliminated, indicating that the proteid food was in excess of that required for the wear and tear of the body. As the quantity of nitrogenous food was diminished almost daily, the N. eliminated was found to diminish also. This latter was in slight excess of that absorbed; but when a day or two's time was allowed, without further reduction in the food, the body tended to adjust itself to the dimished supply, and there was an approximation of income and expenditure. The smallest quantity of food was reached on the 32nd day with 1.06 N. = 6.7 proteid, which was obviously too little, as 2.19 N. = 13.9 proteid was eliminated. On the 21st day 4.12 N. = 26 proteid was injested, and 4.05 N. was eliminated. The inference drawn from the research is that about 26 grammes of proteid per day was sufficient. The weight of the body remained practically constant throughout, and the subject did not suffer inconvenience. Of course the full amount of calories was kept up; as each succeeding quantity of the proteid was left off, it was replaced by a proper quantity of non-nitrogenous food. These experiments were carried out in the usual approved scientific manner. It may, however, be urged against any generalised and positive conclusions as to the minimum quantity of proteid required for the body, being drawn from such experiments, that the period covered by them was much too short. A prolonged trial might have revealed some obscure physiological derangement. We are quite justified in concluding that the usual, so-called "standard dietaries" contain an unnecessarily large proportion of proteid. In some practical dietaries, 50 grammes and under have seemed enough; but for the ordinary adult man, who has been accustomed to an abundance of proteid, and whose ancestors have also, it is probably advisable not to take less than 70 or 80 grammes per day (2-1/2 to 3 ounces). If it is desired to try less, the diminution should be very gradual, and a watch should be kept for any lessening of strength.

Some comments may now be made upon the table of dietaries. That of the London sewing girl contained 53 grammes of proteid, which should have been ample, according to some of the authorities we have given; yet she was badly nourished. The food was doubtless of bad quality, and it appears deficient in carbo-hydrates; this latter is shown by the low number of calories. The long hours and unhealthy conditions of work, and not a deficiency of food constituents, is probably the cause of the bad health of such persons. There is no reason to think the proteid insufficient, although some persons have said as much. We have no particulars of the German vegetarians, but the calories appear satisfactory. In the poor German labourer's family the calories are too low. In Dr. T.R. Allinson's experiment on a wheatmeal dietary, it will not do to assume that less than 82 grammes of proteid would have been insufficient. It is probable that a smaller quantity of proteid would have been enough if the fat and carbohydrates had been increased. The calories are below the usual standard. In the succeeding example the calories are considerably higher, being not far from the usual standard, yet 54 grammes of proteid sufficed. It is a common error to place an undue value on the proteids to the extent of overlooking the other constituents. Dr. Alexander Haig in "Diet and Food," p. 8, cites the case of a boy aged 10, fed on 2-1/4 pints of milk per day. The boy lost weight, and Dr. Haig is of opinion that the quantity of milk was very deficient in proteid; more than twice as much being required. 2-1/4 pints of milk contain about 45 grammes of proteid, whereas, according to the usual figures (125 x 6/10) a boy of this age requires 75 g. This quantity of 45 g. is however, higher, allowing for the boy's age, than that in several of the dietaries we have given in our table. A little consideration will show that Dr. Haig has overlooked the serious deficiency of the milk in the other constituents, which accounts for the boy's loss of weight. The quantity of milk contains only about 160 g. of total solid matter, whilst 400 g. is the necessary quantity. Milk is too rich in proteid matter to form, with advantage, the sole food of a human being. Human milk contains much less in proportion to the other constituents.

The old doctrine enunciated by Justus von Liebig was that proteid matter is the principal source of muscular energy or strength. He afterwards discovered and acknowledged his error, and the subject has since been thoroughly investigated. The makers of meat extracts and other foods, either from their own ignorance of modern research or their wish to take advantage of the lack of knowledge and prejudice of the public, call proteid matter alone nourishment. The carbo-hydrates and fats are equally entitled to be called nourishment.