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Human Foods and Their Nutritive Value
by Harry Snyder
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206. Cayenne.—Cayenne or red pepper is the fruit pod of a plant, capsicum, of which there are several varieties,—the small-fruited kind, used to make cayenne or red pepper; and the tabasco sort, forming the basis of tabasco sauce. It is grown mainly in the tropics, and was used there as a condiment before the landing of Columbus, who took specimens back to Europe. Cayenne pepper contains 25 per cent of oil, about 7 per cent of ash, and a liberal amount of starch. The adulterants are usually of a starchy nature, as rice or corn meal, and the product is often colored with some red dye.

207. Mustard.—Mustard is the seed of the mustard plant, and is most often found in commerce in the ground form. The black or brown mustard has a very small seed and the most aroma. White mustard is much larger and is frequently used unground. For the ground mustard, only the interior of the seed is used, the husk being removed in the bolting. Mustard contains a large amount of oil, part of which is usually expressed before grinding, and this is the form in which spice grinders buy it. In mustard flour there is: ash from 4 to 6 per cent, volatile oil from 0.5 to 2 per cent, fixed oil from 15 to 25 per cent, crude fiber from 2 to 5 per cent, albuminoids from 35 to 45 per cent, and a little starch. The principal adulterants are wheat, corn, and rice flour. When these are used, the product is frequently colored with turmeric, a harmless vegetable coloring material.

208. Ginger.—Ginger is the rhizome or root of a reed-like plant (Zingiber officinale), native in tropical Asia, chiefly India. It is cultivated in nearly all tropical countries. When unground it usually occurs in two forms: dried with the epidermis, or with the epidermis removed, when it is called scraped ginger. Very frequently a coating of chalk is given, as a protection against the drug store beetle. Jamaica ginger is the best and most expensive. Cochin, scraped, African, and Calcutta ginger range in price in the order given. Ginger contains from 3.6 to 7.5 per cent of ash, from 1.5 to 3 per cent of volatile oil, and from 3 to 5.5 per cent of fixed oil. There is a large amount of starch. The chief adulterants are rice, wheat, and potato starch, mustard hulls, exhausted ginger from ginger-ale and extract factories, sawdust and ground peanut-shells, and turmeric is frequently used for coloring the product. The United States standard for ginger is not more than 42 per cent starch, 8 per cent fiber, and 6 per cent total ash.[71]

209. Cinnamon and Cassia.—The bark of several species of plants growing in tropical countries furnishes these spices. True cinnamon is a native of Ceylon, while the cassias are from Bengal and China. In this country there is more cassia used than cinnamon—cinnamon being rarely found except in drug stores. Cassia bark is much thicker than cinnamon bark. The ground spice contains about 1.5 per cent volatile oil and the same amount of fixed oil, 4 per cent of ash, and some fiber, nitrogenous matter, and starch. Cereals, cedar sawdust, ground nutshells, oil meal, and cracker crumbs are the chief adulterants.

210. Cloves.—Cloves are the flower buds of an evergreen tree that grows in the tropics. These are picked by hand and dried in the sun. In the order of value, Penang, Sumatra, Amboyna, and Zanzibar furnish the chief varieties. Cloves rarely contain more than 8 per cent ash, or less than 10 per cent volatile oil and 4 per cent fixed oil, and 16 to 20 per cent of tannin-yielding bodies. No starch is present. The chief adulterants of ground cloves are spent cloves, allspice, and ground nutshells. Clove stems are also sometimes used and may be detected by a microscopical examination, since they contain many thick-walled cells and much fibrous tissue.

211. Allspice.—Allspice, or pimento, is the fruit of an evergreen tree common in the West Indies. It is a small, dry, globular berry, two-celled, each cell having a single seed. Allspice contains about 2.5 per cent volatile oil, 4 per cent fixed oil, and 4.5 per cent ash. Because of its cheapness, it is not generally adulterated, cereal starches being the most common adulterants.

212. Nutmeg.—Nutmeg is the interior kernel of the fruit of a tree growing in the East Indies. The fruit resembles a small pear. A fleshy mantle of crimson color, which is mace, envelopes the seed. Nutmeg contains about 2.2 per cent ash, 2.5 to 5 per cent volatile oil, and 25 to 35 per cent fixed oil. Mace has practically the same composition. Extensive adulteration is seldom practiced. The white coating on the surface of the nutmeg is lime, used to prevent sprouting of the germ.



CHAPTER XIV

TEA, COFFEE, CHOCOLATE, AND COCOA



213. Tea is the prepared leaf of an evergreen shrub or small tree cultivated chiefly in China and Japan. There are two varieties of plants. The Assamese, which requires a very moist, hot climate, yields in India and Ceylon about 400 pounds per acre, and may produce as high as 1000 pounds. From this plant a number of flushes or pickings are secured in a year. The Chinese plant grows in cooler climates and has a smaller, tougher, and darker leaf, which is more delicate than that of the Assamese and is usually made into green tea. The Chinese tea plant yields only four or five flushes a year. About 40 per cent of the tea used in this country comes from Japan and 50 per cent from China. The tea industry of India and Ceylon has developed rapidly in late years, and is now second only to that of China. Tea has been raised upon a small scale in the United States. The quality or grade of the tea depends upon the leaves used and the method of curing.

214. Composition of Tea.—Black and green teas are produced from the same species of plant, but owe their difference in color as well as flavor and odor to methods of preparation. The same plant may yield several grades of both green and black tea. To produce black tea, the leaves are bruised to liberate the juices, allowed to ferment a short time, which develops the color, and then dried.[73] For green tea the fresh leaves are roasted or steamed, then rolled and dried as quickly as possible to prevent fermentation. The smaller leaves and the first picking produce the finest quality of tea. The characteristic flavor and odor of tea are imparted by a volatile oil, although the odor is sometimes altered by the tea being brought in contact with orange flowers, jessamine, or the fragrant olive. There are also present in tea an alkaloid, theine, which gives the peculiar physiological properties, and tannin, upon which depends largely the strength of the tea infusion. The composition of tea is as follows:

=========================================== ORIGINAL GREEN BLACK TEA TEA TEA - Tannin, per cent 12.91 10.64 4.89 Theine, per cent 3.30 3.20 3.30 Ash, per cent 4.97 4.92 4.93 Fiber, per cent 10.44 10.06 10.07 Protein, per cent 37.33 37.43 38.90 (all insoluble) ===========================================

It will be noticed that green tea contains twice as much tannin as black tea; during the fermentation which the black tea undergoes, some of the tannin is decomposed. There is a large amount of protein in tea, but it is of no food value, because of its insolubility. About half of the ash is soluble. The tannin is readily soluble, and for this reason green tea especially should be infused for a very short time and never boiled. Tannin in foods in large amounts may interfere with the normal digestion of the protein compounds, because it coagulates the albumin and peptones after they have become soluble, and thus makes additional work for the digestive organs.

215. Judging Teas.—Teas are judged according to: (1) the tea as it appears prepared for market, (2) the infusion, and (3) the out-turn after infusion. The color should be uniform; if a black tea, it should be grayish black, not a dead black. The leaves should be uniform in size or grade. The quality and grade are dependent upon flavor, and, with the strength of the infusion, are determined by tasting. This work is rapidly done by the trained tea taster. The out-turn should be of one color; no bright green leaves should be present; evenness of make is judged by the out-turn. The flavor of a tea is largely a matter of personal judgment, but from a physiological point of view black teas are given the preference.

216. Adulteration of Tea.—A few years ago tea was quite extensively adulterated, but the strict regulation of the government regarding imported tea has greatly lessened adulteration. The most common form was the use of spent leaves, i.e. leaves which had been infused. Leaves of the willow and other plants which resemble tea were also used, as well as large quantities of tea stems. Facing or coloring is also an adulteration, since it is done to give poor or damaged tea a brighter appearance. "Facing consists in treating leaves damaged in manufacture or which from age are inferior, with a mixture containing Prussian blue, turmeric, indigo, or plumbago to impart color or gloss, and with a fraudulent intent. There is no evidence that the facing agents are deleterious to health in the small quantities used, but as they are used for purposes of deception, they should be discouraged."[73] Facing and the addition of stems are the chief adulterations practiced at present.

217. Food Value and Physiological Properties of Tea.—Tea infusion does not contain sufficient nutrients to entitle it to be classed as a food. It is with some persons a stimulant. The caffein or theine in tea is an alkaloid that has characteristic physiological properties. In doses of from three to five grains, according to the United States Dispensatory, "it produces peculiar wakefulness." Larger doses produce intense physical restlessness, mental anxiety, and obstinate sleeplessness. "It has no effect upon the motor nerves, but is believed to have a visible effect upon the sensatory nerves." (United States Dispensatory.) Experiments with animals show that it causes elevation of the arterial pressure. It is used as a cardiac stimulant. The quantity of theine consumed in a cup of tea is about 4/5 of a grain, or 1/4 of a medicinal dose.



218. Composition of Coffee.—The coffee tree is an evergreen cultivated in the tropics. It grows to a height of 30 feet, but when cultivated is kept pruned to from 6 to 10 feet. The fruit, which resembles a small cherry, with two seeds or coffee grains embedded in the pulp, is dried and the seeds removed, cleaned, and graded. Coffee has an entirely different composition from tea; it is characterized by a high per cent of fat and soluble carbohydrates, and also contains an essential oil and caffein, an alkaloid identical with theine. Tannic acid, not as free acid, is combined with caffein as a tannate.

====================================== RAW COFFEE ROASTED COFFEE Per Cent Per Cent Water 11.23 1.15 Ash 3.92 4.75 Fat 12.27 14.48 Sugar, etc. 0.66 8.55 Protein 12.07 13.98 Caffein 1.21 1.24 ======================================

The high per cent of sugar and other soluble carbohydrates in roasted coffee is caused by the action of heat upon the non-nitrogenous compounds. Coffee cannot be considered a food, because only a comparatively small amount of the nutrients are soluble and available. It is a mildly stimulating beverage. With some individuals it appears to promote the digestive process, while with others its effect is not beneficial. Coffee is more extensively used in this country than tea, and is subject to greater adulteration. It is adulterated by facing and glazing; i.e. coloring the berries to resemble different grades and coating them with caramel and dextrine. Spent coffee grains and coffee that has been extracted without grinding are also used as adulterants. Imitation berries made of rye, corn, or wheat paste, molded, colored with caramel, and baked have been found mixed with genuine coffee berries. Roasted cereals and chicory are used extensively to adulterate ground coffee. Chicory is prepared from the root of the chicory plant, which belongs to the same family as the dandelion. It is claimed by some that a small amount of chicory improves the flavor of coffee. However, when chicory is added to coffee, it should be so stated on the label and the amount used given. The dextrine and sugar used in glazing are browned or caramelized during roasting and impart a darker color to the infusion, making it appear better than it really is. The glazing also makes the coffee retain moisture which would otherwise be driven off during roasting. Coffee contains such a large per cent of oil that the berries generally float when thrown on water, while the imitation berries sink. Chicory also sinks rapidly and colors the water brown, while the coffee remains floating for some time.

There are three kinds of coffee in general use: Java, Mocha, and Rio or Brazil. The Brazil coffee has the largest berry and is usually styled by dealers as "low" or "low middlings." The Java coffee berries are smaller and paler in color, the better grades being brown. Mocha usually commands the highest price in commerce. The seeds are small and dark yellow before roasting.

219. Cereal Coffee Substitutes.

"A few of these preparations contain a little true coffee, but for the most part they appear to be made of parched grains of barley, wheat, etc., or of grain mixed with pea hulls, ground corncobs, or wheat middlings. It is said that barley or wheat parched, with a little molasses, in an ordinary oven, makes something indistinguishable in flavor from some of the cereal coffees on the market. If no coffee is used in the cereal preparations, the claim that they are not stimulating is probably true. As for the nutritive value, parching the cereals undoubtedly renders some of the carbohydrates soluble, and a part of this soluble matter passes into the decoction, but the nutritive value of the infusion is hardly worth considering in the dietary."[56]

220. Cocoa and Chocolate Preparations.—Cocoa and chocolate are manufactured from the "cocoa bean," the seed of a tree native to tropical America. The beans are inclosed in a lemon-yellow, fleshy pod. They are removed from the pulp, allowed to undergo fermentation, and dried by exposure to the air and light, which hardens them and gives them a red color. This method produces what is known as the "fermented cocoa." For the "unfermented cocoa," the beans are dried without undergoing fermentation. Fermentation removes much of the acidity and bitterness characteristic to the unfermented bean, and when properly regulated develops flavor. The original bean contains about 50 per cent fat, part of which is removed in preparing the cocoa. This fat is sold as cocoa butter. In the preparation of some brands of cocoa, alkalies, such as soda and potash, are used to form a combination with the fat to prevent its separating in oily globules. This treatment improves the appearance of the cocoa, but experiments show the albumin to be somewhat less digestible and the soap-like product resulting not as valuable a food as the fat. Such preparations have a high per cent of ash. There is no objection from a nutritive point of view to a cocoa in which the fat separates in oily globules.

221. Composition of Cocoa.—The cocoa bean, when dried or roasted and freed from its husk and ground, is sold as cracked cocoa, or cocoa nibs. From cocoa nibs the various cocoa and chocolate preparations are made. Cocoas vary in composition according to the extent to which the fat is removed during the process of manufacture and the nature and extent to which other ingredients are added. An average cocoa contains about 20 per cent of proteids, and 30 per cent fat, also starch, sugar, gums, fiber, and ash, as well as theobromine, a material very similar to theine and caffein in tea and coffee, but not such an active stimulant. Cocoa is not easily soluble, but it may be ground so fine that a long time is required for its sedimentation; or sugar or other soluble material may be added during the process of manufacture to increase the specific gravity of the liquid to such an extent that the same object is attained without such fine grinding. The first method is to be preferred. Cocoa and its preparations are richer in nutritive substances than tea and coffee and have this added advantage that both the soluble and insoluble portions become a part of the beverage. Owing to the small amount used for a cup of cocoa, independent of the milk it does not add much in the way of nutrients to the ration.

222. Chocolate.—Plain chocolate is prepared from cocoa nibs without "removal of the fat or other constituents except the germ." It differs in chemical composition from cocoa by containing more fat and less protein; it has nearly the same chemical composition as the cocoa nibs. It is officially defined as containing "not more than 3 per cent of ash insoluble in water, 3-1/2 per cent of crude fiber and 9 per cent of starch, and less than 45 per cent cocoa fat."[71]

By the addition of sugar, sweet chocolates are made. They vary widely in composition according to the flavors and amounts of sugar added during their preparation. The average composition of cocoa nibs, standard cocoa, and plain chocolate is as follows:

============================================================== COCOA COMPOSITION OF COMPOSITION OF NIBS STANDARD COCOA PLAIN CHOCOLATE - Per Cent Per Cent Per Cent Water 3.00 3.09 Ash 3.50 4.20 3.08 Theobromine 1.00 Caffein 0.50 Crude Protein 12.00 Crude fiber 2.50 5.02 2.63 Fat 50.00 32.52 49.81 Starch and other non-nitrogenous matter 27.50 ============================================================

223. Adulteration of Chocolate and Cocoa.—The various chocolate and cocoa preparations offer an enticing field for sophistication; they are not, however, so extensively adulterated as before the enforcement of national and state pure food laws. The most common adulterants are starch, cocoa shells, and occasionally iron dioxid and other pigments to give color, also foreign fats to replace the fat removed and to give the required plasticity for molding.

224. Comparative Composition of Beverages.—Tea and coffee as beverages contain but little in the way of nutrients other than the cream and sugar used in them. The solid matter in tea and coffee infusions amounts to less than 1.2 per cent. When cocoa is made with milk, it is a beverage of high nutritive value due mainly to the milk.

COMPOSITION OF BEVERAGES[56]

============================================================================= FUEL KIND OF BEVERAGE WATER PROTEIN FAT CARBO- VALUE HYDRATES PER LB. Per Cent Per Cent Per Cent Per Cent Calories Commercial cereal coffee (0.5 ounce to 1 pint water) 98.2 0.2 1.4 30 Parched corn coffee (1.6 ounces to 1 pint water) 99.5 0.2 0.5 13 Oatmeal water (1 ounce to 1 pint water) 99.7 0.3 0.3 11 Coffee (1 ounce 1 pint water) 98.9 0.2 0.7 16 Tea (0.5 ounce to 1 pint water) 99.5 0.2 0.6 15 Cocoa (0.5 ounce to 1 pint milk) 84.5 3.8 4.7 6.0 365 Cocoa (0.5 ounce to 1 pint water) 97.1 0.6 0.9 1.1 65 Skimmed milk 90.5 3.4 0.3 5.1 170 =============================================================================



CHAPTER XV

THE DIGESTIBILITY OF FOODS

225. Digestibility, How Determined.—The term "digestibility," as applied to foods, is used in two ways: (1) meaning the thoroughness of the process, or the completeness with which the nutrients of the food are absorbed and used by the body, and (2) meaning the ease or comfort with which digestion is accomplished. Cheese is popularly termed indigestible, and rice digestible, when in reality the nutrients of cheese are more completely although more slowly digested than those of rice. In this work, unless otherwise stated, digestibility is applied to the completeness of the digestion process.

The digestibility of a food is ascertained by means of digestion experiments, in which all of the food consumed for a certain period, usually two to four days, is weighed and analyzed, and from the weight and composition is determined the amount, in pounds or grams, of each nutrient consumed.[72] In like manner the nutrients in the indigestible portion, or feces, are determined from the weight and composition of the feces. The indigestible nutrients in the feces are deducted from the total nutrients of the food, the difference being the amount digested, or oxidized in the body. When the food is digested, the various nutrients undergo complete or partial oxidation, with the formation of carbon dioxid gas, water, urea (CH{4}N{2}O), and other compounds. The feces consist mainly of the compounds which have escaped digestion. The various groups of compounds of foods do not all have the same digestibility; for example, the starch of potatoes is 92 per cent digestible, while the protein is only 72 per cent. The percentage amount of a nutrient that is digested is called the digestion coefficient.

In the following way the digestibility of a two-days ration of bread and milk was determined: 773.5 grams of bread and 2000 grams of milk were consumed by the subject. The dried feces weighed 38.2 grams. The foods and feces when analyzed were found to have the following composition:[62]

===================================================================== COMPOSITION BREAD MILK FECES[A] - Water 44.13 86.52 Crude protein 7.75 3.15 25.88 Ether extract 0.90 4.63 18.23 Ash 0.32 0.70 26.35 Carbohydrates 46.90 5.00 29.54 Calories per gram 2.450 0.79 5.083 =====================================================================

[Footnote A: Results on dry-matter basis.]

STATEMENT OF RESULTS OF A DIGESTION EXPERIMENT

============================================================================= FOOD CONSUMED WEIGHT PROTEIN ETHER CARBO- HEAT OF OF N x 6.25 EXTRACT HY- ASH COMBUS- MATERIAL DRATES TION - - - Grams Grams Grams Grams Grams Calories Bread 773.5 60.0 6.9 362.8 2.5 1895 Milk 2000.0 63.0 92.6 100.0 14.0 1585 - + - + - - - Total 38.2 123.0 99.5 462.8 16.5 3480 Feces 9.9 7.0 11.3 10.1 194 - + - + - - - Total amount 113.1 92.5 451.5 6.4 3286 digested Per cent digested or coefficients of digestibility 92.0 93.0 97.5 38.8 94.4 Available energy 90.0 =============================================================================

In this experiment 92 per cent of the crude protein, 93 per cent of the ether extract, and 97.5 per cent of the carbohydrates of the bread and milk ration were digested and absorbed by the body. In calculating the available energy, correction is made for the unoxidized residue, as urea and allied forms. It is estimated that for each gram of protein in the ration there was an indigestible residue yielding 1.25 calories.

226. Available Nutrients.—A food may contain a comparatively large amount of a compound, and yet, on account of its low digestibility, fail to supply much of it to the body in an available form. Hence it is that the value of a food is dependent not alone on its composition, but also on its digestibility. The digestible or available nutrients of a food are determined by multiplying the per cent of each nutrient which the food contains by its digestion coefficient. For example, a sample of wheat flour contains 12 per cent protein, 88 per cent of which is digestible, making 10.56 per cent of available or digestible protein (12 x 0.88-10.56). Graham flour made from similar wheat contains 13 per cent total protein, and only 75 per cent of the protein is digestible, making 9.75 per cent available (13 x 0.75 = 9.75). Thus one food may contain a larger total but a smaller available amount of a nutrient than another.

227. Available Energy.—The available energy of a food or a ration is expressed in calories. A ration for a laborer at active out-of-door work should yield about 3200 calories. The calory is the unit of heat, and represents the heat required to raise the temperature of a kilogram of water 1 deg. C., or four pounds of water 1 deg. F. The caloric value of foods is determined by the calorimeter, an apparatus which measures heat with great accuracy. A pound of starch, or allied carbohydrates, yields 1860 calories, and a pound of fat 4225 (see Section 13). While a gram of protein completely burned produces 7.8 calories, digested it yields only about 4.2 calories, because, as explained in the preceding section, not all of the carbon and oxygen are oxidized.[59] The caloric value or available energy of a ration can be calculated from the digestible nutrients by multiplying the pounds of digestible protein and carbohydrates by 1860, the digestible fat by 4225, and adding the results. For determination of the available energy of foods under different experimental conditions, and where great accuracy is desired, a specially constructed respiration calorimeter has been devised, which is built upon the same principle as an ordinary calorimeter, except it is large enough to admit a person, and is provided with appliances for measuring and analyzing the intake and outlet of air.[74] The heat produced by the combustion of the food in the body warms the water surrounding the calorimeter chamber, and this increase in temperature is determined by thermometers reading to 0.005 of a degree or less.



228. Normal Digestion and Health.—While the process of digestion has been extensively studied, it is not perfectly understood. Between the initial compounds of foods and their final oxidation products a large number of intermediate substances are formed, and when digestion fails to take place in a normal way, toxic or poisonous compounds are produced and various diseases result. It is probable that more diseases are due to imperfect or malnutrition than to any other cause. There is a very close relationship between health and normal digestion of the food.

The cells in the different parts of the digestive tract secrete fluids containing substances known as soluble ferments, or enzymes, which act upon the various compounds of foods, changing them chemically and physically so that they can be absorbed and utilized by the body. (See Section 31.) Some of the more important ferments are: ptyolin of the saliva, pepsin of the stomach, and pancreatin and diastase of the intestines. In order that these ferments may carry on their work in a normal way, the acidity and alkalinity of the different parts of the digestive tract must be maintained. The gastric juice contains from 0.1 to 0.25 per cent of hydrochloric acid, imparting mildly antiseptic properties; and while the peptic ferment works in a slightly acid solution, the tryptic ferment requires an alkaline solution. To secrete the necessary amount and quality of digestive fluids, the organs must be in a healthy condition. Many erroneous ideas regarding the digestion of foods are based upon misinterpretation of facts by persons suffering from impaired digestion, and attempts are frequently made to apply to normal digestion generalizations applicable only to diseased conditions.

229. Digestibility of Animal Foods.—The proteids and fats in animal foods, as meats, are more completely digested than the same class of nutrients in vegetables. In general, about 95 per cent of the proteids of meats is digestible, while those in vegetables are often less than 85 percent digestible. The amount of indigestible residue from animal foods is small; while from vegetables it is large, for the cellulose prevents complete absorption of the nutrients and, as a result, there is much indigestible residue. Animal foods are concentrated, in that they furnish large amounts of nutrients in digestible forms. There is less difference in the completeness with which various meats are digested than in their ease of digestion; the proteins all have about the same digestion coefficients, but vary with individuals as to ease of digestion and time required. It is generally considered that the digestible proteins, whether of animal or vegetable origin, are equally valuable for food purposes. This is an assumption, however, that has not been well established by experimental evidence. In a mixed ration, the proteins from different sources appear to have the same nutritive value, but as each is composed of different radicals and separated into dissimilar elementary compounds during the process of digestion, they would not necessarily all have the same food value.

There is but little difference between the fats and proteins of meats as to completeness of digestion,—the slight difference being in favor of the proteins. Some physiologists claim that the fat, which in some meats surrounds the bundles of fiber (protein), forming a protecting coat, prevents the complete solvent action of the digestive fluid. Very fat meats are not as completely digested as those moderately fat. It is also claimed that the digestibility of the meat is influenced by the mechanical character, as toughness of the fiber.

230. Digestibility of Vegetable Foods.—Vegetable foods vary in digestibility with their mechanical condition and the amount of cellulose or fiber. In some the nutrients are so embedded in cellular tissue as to be protected from the solvent action of the digestive fluids, and in such cases the digestibility and availability are low. The starches and sugars are more completely digested than any other of the nutrients of vegetables; in some instances they are from 95 to 98 per cent digestible. Some cellular tissue, but not an excess, is desirable in a ration, as it exerts a favorable mechanical action upon the organs of digestion, encourages peristalsis, and is an absorbent and dilutant of the waste products formed during digestion. For example, in the feeding of swine, it has been found that corn and cob meal often gives better results than corn fed alone. The cob contains but little in the way of nutrients, but it exerts a favorable mechanical action upon digestion. Occasionally too many bulky foods are combined, containing scant amounts of nutrients, so that the body receives insufficient protein. This is liable to be the case in the dietary of the strict vegetarian. Many of the vegetables possess special dietetic value, due to the organic acids and essential oils, as cited in the chapter on fruits and vegetables. The value of such foods cannot always be determined from their content of digestible protein, fat, and carbohydrates. This is particularly evident when they are omitted from the ration, as in the case of a restricted diet consisting mainly of animal foods. Many vegetables have low nutritive value on account of their bulky nature and the large amount of water and cellulose which they contain, which tends to decrease digestibility and lower the amount of available nutrients. Because of their bulk and fermentable nature, resulting in the formation of gases, a diet of coarse vegetables has a tendency to cause distention and enlargement of the intestinal organs. The carbohydrates, which are the chief constituents of vegetables, are digested mainly in the intestines, and require special mechanical preparation in the stomach, hence the nutrients of vegetables are not, as a rule, as easily digested as those of animal foods.

231. Factors influencing Digestion.—There are a number of factors which influence completeness as well as ease of digestion, as: (1) combination of foods; (2) amount of food; (3) method of preparation; (4) mechanical condition of the food; (5) palatability; (6) physiological properties; (7) individuality of the consumer; and (8) psychological influences.

232. Combination of Foods.—In a mixed ration the nutrients are generally more completely digested than when only one food is used. For example, milk is practically all digested when it forms a part of a ration, and it also promotes digestibility of the foods with which it is combined, but when used alone it is less digestible.[27] Bread alone and milk alone are not as completely digested as bread and milk combined. The same in a general way has been observed in the feeding of farm animals,—better results are secured from combining two or more foods than from the use of one alone. The extent to which one food influences the digestibility of another has not been extensively studied.

In a mixed ration, consisting of several articles of food of different mechanical structure, the work of digestion is more evenly distributed among the various organs. A food often requires special preparation on the part of the stomach before it can be digested in the intestines, and if this food is consumed in small amounts and combined with others of different structure, the work of gastric digestion is lessened so that the foods are properly prepared and normal digestion takes place. The effect which one food exerts upon the digestibility of another is largely mechanical.

233. Amount of Food.—Completeness as well as ease of digestion is influenced by the amount of food consumed. In general, excessive amounts are not as completely digested as moderate amounts. In digestion experiments with oatmeal and milk, it was found that when these foods were consumed in large quantities the fat and protein were not as completely absorbed by the body as when less was used, the protein being 7 per cent and the fat 6 per cent more digestible in the medium ration. Experiments with animals show that economical results are not secured from an excess of food.[5] Some individuals consume too much food, and with them a restricted diet would be beneficial, while others err in not consuming enough to meet the requirements of the body. Quite frequently it is those who need more food who practice dieting. When there is trouble with digestion, it is not always the amount or kind of food which is at fault, but other habits may be such as to affect digestion. The active out-of-door laborer can with impunity consume more food, because there is greater demand for nutrients, and the food is more completely oxidized in the body and without the formation of poisonous waste products. The amount of food consumed should be sufficient to meet all the demands of the body and maintain a normal weight.

234. Method of Preparation of Food.—The extent to which methods of cooking and preparation influence completeness of digestion has not been extensively investigated. As is well known, they have great influence upon ease and comfort of digestion. During cooking, as discussed in Chapter II, extensive physical and chemical changes occur, and these in turn affect digestibility. When the cooking has not been sufficient to mechanically disintegrate vegetable tissue, the digestive fluids fail to act favorably upon the food. Cooking is also beneficial because it renders the food sterile and destroys all objectionable microoerganisms which, if they remain in food, readily undergo incubation in the digestive tract, interfering with normal digestion. Prolonged heat causes some foods to become less digestible, as milk, which digestion experiments show to be more completely digested when fresh than when sterilized. Pasteurized milk, which is not subjected to so high a temperature as sterilized milk, is more completely digested. See Chapter VII for discussion of sterilizing and pasteurizing milk.[38] The benefits derived from the destruction of the objectionable bacteria in foods are, however, greater than the losses attendant on lessened digestibility due to the action of heat. The method of preparation of a food affects its digestibility mainly through change in mechanical structure, and modification of the forms in which the nutrients are present.[5]

235. Mechanical Condition of Foods.—The mechanical condition of foods as to density and structure of the particles and the extent to which they are disintegrated in their preparation for the table influences digestibility to a great extent. The mechanics of digestion is a subject that has not been extensively investigated, and it is one of great importance, as biological and chemical changes cannot take place if the food is not in proper mechanical condition. In general, the finer the food particles, the more completely the nutrients are acted upon by the digestive fluids and absorbed by the body. Nevertheless, the diet should not consist entirely of finely granulated foods. Some foods are valuable mainly because of the favorable action they exert mechanically upon digestion, rather than for the nutrients they contain.[62] Coarsely granulated breakfast foods, whole wheat flour, and many vegetables contain sufficient cellular tissue to give special value from a mechanical rather than a chemical point of view. The extent to which coarsely and finely granulated foods should enter into the ration is a question largely for the individual to determine. Experiments with pigs show that if large amounts of coarse, granular foods are consumed, the tendency is for the digestive tract to become inflamed and less able to exercise its normal functions. Coarsely granulated foods have a tendency to pass through the digestive tract in less time than those that are finely granulated, due largely to increased peristaltic action, and the result is the food is not retained a sufficient length of time to allow normal absorption to take place. In the feeding of farm animals, it has been found that the mechanical condition of the food has a great influence upon its economic use. Rations that are either too bulky or too concentrated fail to give the best results. In the human ration, the mechanical condition of the food is equally as important as its chemical composition.

236. Mastication is an important part of digestion, and when foods are not thoroughly masticated, additional work is required of the stomach, which is usually an overworked organ because of doing the work of the mouth as well. Although much of the mechanical preparation and mixing of foods is of necessity done in the stomach, some of it may advantageously be done in the mouth. The stomach should not be required to perform the function of the gizzard of a fowl.

237. Palatability of Foods.—Many foods naturally contain essential oils and other substances which impart palatability. These have but little in the way of nutritive value, but they assist in rendering the nutrients with which they are associated more digestible. Palatability of a food favorably influences the secretion of the gastric and other digestive fluids, and in this way the natural flavors of well-prepared foods aid in digestion. In the feeding of farm animals it has been found that when foods are consumed with a relish better returns are secured than when unpalatable foods are fed. To secure palatability the excessive use of condiments is unnecessary. It is possible to a great extent during preparation to develop and conserve the natural flavors. Some foods contain bitter principles which are removed during the cooking, while in others pleasant flavors are developed. Palatability is an important factor in the digestibility of foods.

238. Physiological Properties of Food.—Some food materials, particularly fruits and vegetables, contain compounds which have definite physiological properties, as tannin which is an astringent, special oils which exert a cathartic action, and the alkaloids which serve as irritants to nerve centers. Wheat germ oil is laxative, and it is probable that the physiological properties of graham and whole wheat breads are due in some degree to the oil which they contain.[67] The use of fruits, herbs, and vegetables for medicinal purposes is based upon the presence of compounds possessing well-defined medicinal properties. As a rule food plants do not contain appreciable amounts of such substances, and the use of food for medicinal effect should be by the advice of a physician. The physiological properties of some foods are due to bacterial products. See Chapter XX.

239. Individuality.—Material difference in digestive power is noticeable among individuals. Digestion experiments show that one person may digest 5 per cent more of a nutrient than another. This difference appears to be due to a number of factors, as activity of the organs, as affected by exercise and kind of labor performed; abnormal composition of the digestive fluids; or failure of the different parts of the digestive tract to act in harmony. Individuality is one of the most important factors in digestion. Persons become accustomed to certain foods through long usage, and the digestive tract adapts itself to those foods, rendering sudden and extreme changes in the dietary hazardous. Common food articles may fail to properly digest in the case of some individuals, while with others they are consumed with benefit. What is food to one may prove to be a poison to another, and while general statements can be made in regard to the digestibility of foods, individual differences must be recognized.

240. Psychological Factors.—Previously conceived ideas concerning foods influence digestibility. Foods must be consumed with a relish in order to secure the best results, as flow of the digestive fluids and activity of the organs are to a certain extent dependent upon the nerve centers. If it is believed that a food is poisonous or injurious, even when the food is wholesome, normal digestion fails to take place. In experiments by the author, in which the comparative digestibility of butter and oleomargarine was being studied, it was found that when the subjects were told they were eating oleomargarine, its digestibility was depressed 5 per cent, and when they were not told the nature of the material, but assumed that butter was oleomargarine, the digestibility of the butter was lowered about 6 per cent.[13] Preconceived notions in regard to foods, not founded upon well-established facts, but due to prejudice resulting from ignorance, cause many valuable foods to be excluded from the dietary. Many persons, like the foreign lady who, visiting this country, said she ate only acquaintances, prefer foods that have a familiar taste and appearance, and any unusual taste or appearance detracts from the value because of the psychological influence upon digestion.



CHAPTER XVI

COMPARATIVE COST AND VALUE OF FOODS

241. Cost and Nutrient Content of Foods.—The market price and the nutritive value of foods are often at variance, as those which cost the most frequently contain the least nutrients.[75] It is difficult to make absolute comparisons as to the nutritive value of foods at different prices, because they differ not only in the amounts, but also in the kinds of nutrients. While it is not possible to express definitely the value of one food in terms of another, approximate comparisons may be made as to the amounts of nutrients that can be secured for a given sum of money when foods are at different prices, and tables have been prepared making such comparisons.



242. Nutrients Procurable for a Given Sum.[7]—To ascertain the nutrients procurable for a given sum first determine the amount in pounds that can be obtained, say, for ten cents, and then multiply by the percentages of fat, protein, carbohydrates, and calories in the food. The results are the amounts, in pounds, of nutrients procurable for that sum of money. For example: if milk is 5 cents per quart, two quarts or approximately four pounds, can be procured for 10 cents. If the milk contains fat, 4 per cent, protein, 3.3 per cent, carbohydrates, 5 per cent, and fuel value, 310 calories per pound, multiplying each of these by 4 gives the nutrients and fuel value in four pounds, or 10 cents worth of milk, as follows:

Protein 0.13 lb. Fat 0.16 lb. Carbohydrates 0.2 lb. Calories 1240

If it is desired to compare milk at 5 cents per quart with round steak at 15 cents per pound, 10 cents will procure 0.66, or two thirds of a pound of round steak containing on an average (edible portion) 19 per cent protein, 12.8 per cent fat, and yielding 890 calories per pound. If 10 per cent is refuse, there is edible about 0.6 of a pound. The amounts of nutrients in the 0.6 of a pound of steak, edible portion, or 0.66 lb. as purchased would be:

Protein 0.11 lb. Fat 0.08 lb. Calories 534

It is to be observed that from the 10 cents' worth of milk a little more protein, 0.08 of a pound more fat, and nearly two and one half times as many calories can be secured as from the 10 cents' worth of meat. This is due to the carbohydrates and the larger amount of fat which the milk contains. At these prices, milk should be used liberally in the dietary, as it furnishes more of all the nutrients than does meat. It would not be advisable to exclude meat entirely from the ration, but milk at 5 cents per quart is cheaper food than meat at 15 cents per pound. In making comparisons, preference cannot always be given to one food because of its containing more of any particular nutrient, for often there are other factors that influence the value.

243. Comparing Foods as to Nutritive Value.—In general, preference should be given to foods which supply the most protein, provided the differences between the carbohydrates and fats are not large. When the protein content of two foods is nearly the same, but the fats and carbohydrates differ materially, the preference may safely be given to the food which supplies the larger amount of total nutrients. A pound of protein in a ration is more valuable than a pound of either fat or carbohydrates, although it is not possible to establish an absolute scale as to the comparative value of these nutrients, because they serve different functional purposes in the body. It is sometimes necessary to use small amounts of foods rich in protein in order to secure a balanced ration; excessive use of protein, however, is not economical, as that which is not needed for functional purposes is converted into heat and energy which could be supplied as well by the carbohydrates, and they are less expensive nutrients.



TEN CENTS WILL PURCHASE: (From Farmer's Bulletin No. 142, U. S. Dept. of Agr.)

============================================================================= TOTAL WEIGHT KIND OF FOOD PRICE OF FOOD CAR- MATERIAL PER MATE- PROTEIN FAT BOHY- ENERGY POUND RIAL DRATES - - - - - Cents Pounds Pound Pound Pounds Calories Beef, sirloin 25 0.40 0.06 0.06 410 Do. 20 0.50 0.08 0.08 515 Do. 15 0.67 0.10 0.11 685 Beef, round 16 0.63 0.11 0.08 560 Do. 14 0.71 0.13 0.09 630 Do. 12 0.83 0.15 0.10 740 Beef, shoulder clod 12 0.83 0.13 0.08 595 Do. 9 1.11 0.18 0.10 795 Beef, stew meat 5 2.00 0.29 0.23 1530 Beef, dried, chipped 25 0.40 0.10 0.03 315 Mutton chops, loin 16 0.63 0.08 0.17 890 Mutton, leg 20 0.50 0.07 0.07 445 Do. 16 0.63 0.09 0.09 560 Roast pork, loin 12 0.83 0.11 0.19 1035 Pork, smoked ham 22 0.45 0.06 0.14 735 Do. 18 0.56 0.08 0.18 915 Pork, fat salt 12 0.83 0.02 0.68 2950 Codfish, dressed, fresh 10 1.00 0.11 220 Halibut, fresh 18 0.56 0.08 0.02 265 Cod, salt 7 1.43 0.22 0.01 465 Mackerel, salt, dressed 10 1.00 0.13 0.20 1135 Salmon, canned 12 0.83 0.18 0.10 760 Oysters, solids, 50 cents per quart 25 0.40 0.02 0.01 90 35 cents per quart 18 0.56 0.03 0.01 0.02 125 Lobster, canned 18 0.56 0.10 0.01 225 Butter 20 0.50 0.01 0.40 1705 Do. 25 0.40 0.32 1365 Do. 30 0.33 0.27 1125 Eggs, 36 cents per dozen 24 0.42 0.05 0.04 260 Eggs, 24 cents per dozen 16 0.63 0.07 0.06 385 Eggs, 12 cents per dozen 8 1.25 0.14 0.11 770 Cheese 16 0.63 0.16 0.20 0.02 1185 Milk, 7 cents per quart 3-1/2 2.85 0.09 0.11 0.14 885 Milk, 6 cents per quart 3 3.33 0.11 0.13 0.17 1030 Wheat flour 3 3.33 0.32 0.03 2.45 5440 Do. 2-1/2 4.00 0.39 0.04 2.94 6540 Corn meal, granular 2-1/2 4.00 0.31 0.07 2.96 6540 Wheat breakfast food 7-1/2 1.33 0.13 0.02 0.98 2235 Oat breakfast food 7-1/2 1.33 0.19 0.09 0.86 2395 Oatmeal 4 2.50 0.34 0.16 1.66 4500 Rice 8 1.25 0.08 0.97 2025 Wheat bread 6 1.67 0.13 0.02 0.87 2000 Do. 5 2.00 0.16 0.02 1.04 2400 Do. 4 2.50 0.20 0.03 1.30 3000 Rye bread 5 2.00 0.15 0.01 1.04 2340 Beans, white, dried 5 2.00 0.35 0.03 1.16 3040 Cabbage 2-1/2 4.00 0.05 0.01 0.18 460 Celery 5 2.00 0.02 0.05 130 Corn, canned 10 1.00 0.02 0.01 0.18 430 Potatoes, 90 cents per bushel 1-1/2 6.67 0.10 0.01 0.93 1970 60 cents per bushel 1 10.00 0.15 0.01 1.40 2950 45 cents per bushel 3/4 13.33 0.20 0.01 1.87 3935 Turnips 1 10.00 0.08 0.01 0.54 1200 Apples 1-1/2 6.67 0.02 0.02 0.65 1270 Bananas 7 1.43 0.01 0.01 0.18 370 Oranges 6 1.67 0.01 0.13 250 Strawberries 7 1.43 .01 0.01 0.09 215 Sugar 6 1.67 1.67 2920 =============================================================================

It is to be noted in the table that, ordinarily, for the same amount of money the most nutrients can be obtained in the form of milk, cheese, sugar, and beans, corn meal, wheat flour, oatmeal, and cereals in bulk. While meats supply protein liberally, they fail to furnish carbohydrates as the vegetables. As discussed in the chapter on Dietary Studies of Families, unnecessarily expensive foods are often used, resulting either in lack of nutrients or unbalanced rations.

EXAMPLES

1. Compute the calories and the amounts of protein, fat, and carbohydrates that can be procured for 25 cents in cheese selling for 18 cents per pound; how do these compare with the nutrients in eggs at 20 cents per dozen?

2. Which food furnishes the larger amount of nutrients, potatoes at 50 cents per bushel or flour at $6 per barrel?

3. How do beans at 10 cents per quart compare in nutritive value with beef at 15 Cents per pound?

4. How does salt codfish at 10 cents per pound compare in nutritive value with lamb chops at 15 cents per pound?

5. Compare in nutritive value cream at 25 cents per quart with butter at 30 cents per pound.

6. Calculate the composition and nutritive value of a cake made of sugar, 8 oz.; butter, 4 oz.; eggs, 8 oz.; flour, 8 oz.; and milk, 4 oz.; the baked cake weighs one and three fourths pounds.

AVERAGE COMPOSITION OF COMMON AMERICAN FOOD PRODUCTS

(From Farmer's Bulletin, No. 142, U. S. Dept. of Agr.)

============================================================================= F h u p R P C y e e e W r a d l r f a o F r r A Food Material u t t a b a s v P (as purchased) s e e t o t h a o e r i - e l u n s u n e d + + + + + -+ -+ Calo- ANIMAL FOOD % % % % % % ries Beef, fresh: Chuck ribs 16.3 52.6 15.5 15.0 0.8 910 Flank 10.2 54.0 17.0 19.0 0.7 1105 Loin 13.3 52.5 16.1 17.5 0.9 1025 Porterhouse steak 12.7 52.4 19.1 17.9 0.8 1100 Sirloin steak 12.8 54.0 16.5 16.1 0.9 975 Neck 27.6 45.9 14.5 11.9 0.7 1165 Ribs 20.8 43.8 13.9 21.2 0.7 1135 Rib rolls 63.9 19.3 16.7 0.9 1055 Round 7.2 60.7 19.0 12.8 1.0 890 Rump 20.7 45.0 13.8 20.2 0.7 1090 Shank, fore 36.9 42.9 12.8 7.3 0.6 545 Shoulder and clod 16.4 56.8 16.4 9.8 0.9 715 Fore quarter 18.7 49.1 14.5 17.5 0.7 995 Hind quarter 15.7 50.4 15.4 18.3 0.7 1045 Beef, corned, canned, pickled, dried: Corned beef 8.4 49.2 14.3 23.8 4.6 1245 Tongue, pickled 6.0 58.9 11.9 19.2 4.3 1010 Dried, salted, and smoked 4.7 53.7 26.4 6.9 8.9 790 Canned boiled beef 51.8 25.5 22.5 1.3 1410 Canned corned beef 51.8 26.3 18.7 4.0 1270 Veal: Breast 21.3 52.0 15.4 11.0 0.8 745 Leg 14.2 60.1 15.5 7.9 0.9 625 Leg cutlets 3.4 68.3 20.1 7.5 1.0 695 Fore quarter 24.5 54.2 15.1 6.0 0.7 535 Hind quarter 20.7 56.2 16.2 6.6 0.8 580 Mutton: Flank 9.9 39.0 13.8 36.9 0.6 1770 Leg, hind 18.4 51.2 15.1 14.7 0.8 890 Loin chops 16.0 42.0 13.5 28.3 0.7 1415 Fore quarter 21.2 41.6 12.3 24.5 0.7 1235 Hind quarter, without 17.2 45.4 13.8 23.2 0.7 1210 tallow Lamb: Breast 10.1 45.5 15.4 19.1 0.8 1075 Leg, hind 17.4 52.9 15.9 13.6 0.9 860 Pork, fresh: Ham 10.7 48.0 13.5 25.9 0.8 1320 Loin chops 19.7 41.8 13.4 24.2 0.8 1245 Shoulder 12.4 44.9 12.0 29.8 0.7 1450 Tenderloin 66.5 18.9 13.0 1.0 895 Pork, salted, cured, pickled: Ham, smoked 13.6 34.8 14.2 33.4 4.2 1635 Shoulder, smoked 18.2 36.8 13.0 26.6 5.5 1335 Salt pork 7.9 1.9 86.2 3.9 3555 Bacon, smoked 7.7 17.4 9.1 62.2 4.1 2715 Sausage: Bologna 3.3 55.2 18.2 19.7 3.8 1155 Pork 39.8 13.0 44.2 1.1 2.2 2075 Frankfort 57.2 19.6 18.6 1.1 3.4 1155 Soups: Celery, cream of 88.6 2.1 2.8 5.0 1.5 235 Beef 92.9 4.4 0.4 1.1 1.2 120 Meat stew 84.5 4.6 4.3 5.5 1.1 365 Tomato 90.0 1.8 1.1 5.6 1.5 185 Poultry: Chicken, broilers 41.6 43.7 12.8 1.4 0.7 305 Fowls 25.9 47.1 13.7 12.3 0.7 765 Goose 17.6 38.5 13.4 29.8 0.7 1475 Turkey 22.7 42.4 16.1 18.4 0.8 1060 Fish: Cod, dressed 29.9 58.5 11.1 0.2 0.8 220 Halibut, steaks or sections 17.7 61.9 15.3 4.4 0.9 475 Mackerel, whole 44.7 40.4 10.2 4.2 0.7 370 Perch, yellow dressed 35.1 50.7 12.8 0.7 0.9 275 Shad, whole 50.1 35.2 9.4 4.8 0.7 380 Shad, roe 71.2 20.9 3.8 2.6 1.5 600 Fish, preserved: Cod, salt 24.9 40.2 16.0 0.4 18.5 325 Herring, smoked 44.4 19.2 20.5 8.8 7.4 755 Fish, canned Salmon 63.5 21.8 12.1 2.6 915 Sardines [A]5.0 53.6 23.7 12.1 5.3 950 Shellfish: Clams 80.8 10.6 1.1 5.2 2.3 340 Crabs 52.4 36.7 7.9 0.9 0.6 1.5 200 Lobsters 61.7 30.7 5.9 0.7 0.2 0.8 145 Eggs: Hen's eggs [B] 11.2 65.5 13.1 9.3 0.9 635 Dairy products, etc.: Butter 11.0 1.0 85.0 3.0 3410 Whole milk 87.0 3.3 4.0 5.0 0.7 310 Skim milk 90.5 3.4 0.3 5.1 0.7 165 Buttermilk 91.0 3.0 0.5 4.8 0.7 160 Condensed milk 26.9 8.8 8.3 54.1 1.9 1430 Cream 74.0 2.5 18.5 4.5 0.5 865 Cheese, Cheddar 27.4 27.7 36.8 4.1 4.0 2075 Cheese, full cream 34.2 25.9 33.7 2.4 3.8 1885 VEGETABLE FOOD Flour, meal, etc.: Entire wheat flour 11.4 13.8 1.9 71.9 1.0 1650 Graham flour 11.3 13.3 2.2 71.4 1.8 1645 Wheat flour, patent roller process High-grade and medium 12.0 11.4 1.0 75.1 0.5 1635 Low grade 12.0 14.0 1.9 71.2 0.9 1640 Macaroni, vermicelli, etc 10.3 13.4 0.9 74.1 1.3 1645 Wheat breakfast food 9.6 12.1 1.8 75.2 1.3 1680 Buckwheat flour 13.6 6.4 1.2 77.9 0.9 1605 Rye flour 12.9 6.8 0.9 78.7 0.7 1620 Corn meal 12.5 9.2 1.9 75.4 1.0 1635 Oat breakfast food 7.7 16.7 7.3 66.2 2.1 1800 Rice 12.3 8.0 0.3 79.0 0.4 1620 Tapioca 11.4 0.4 0.1 88.0 0.1 1650 Starch 90.0 1675 Bread, pastry, etc.: White bread 35.3 9.2 1.3 53.1 1.1 1200 Brown bread 43.6 5.4 1.8 47.1 2.1 1040 Bread, pastry, etc.: Graham bread 35.7 8.9 1.8 52.1 1.5 1195 Whole wheat bread 38.4 9.7. 0.9 49.7 1.3 1130 Rye bread 35.7 9.0. 0.6 53.2 1.5 1170 Cake 19.9 6.3. 9.0 63.3 1.5 1630 Cream crackers 6.8 9.7. 12.1 69.7 1.7 1925 Oyster crackers 4.8 11.3. 10.5 70.5 2.9 1910 Soda crackers 5.9 9.8. 9.1 73.1 2.1 1875 Sugars, etc.: Molasses 70.0 1225 Candy[C] 96.0 1680 Honey 81.0 1420 Sugar, granulated 100.0 1750 Maple sirup 71.4 1250 Vegetables:[D] Beans, dried 12.6 22.5. 1.8 59.6 3.5 1520 Beans, Lima, shelled 68.5 7.1. 0.7 22.0 1.7 540 Beans, string 7.0 83.0 2.1. 0.3 6.9 0.7 170 Beets 20.0 70.0 1.3. 0.1 7.7 0.9 160 Cabbage 15.0 77.7 1.4. 0.2 4.8 0.9 115 Celery 20.0 75.6 0.9. 0.1 2.6 0.8 65 Corn, green (sweet), edible portion 75.4 3.1 1.1 19.7 0.7 440 Cucumbers 15.0 81.1 0.7. 0.2 2.6 0.4 65 Lettuce 15.0 80.5 1.0. 0.2 2.5 0.8 65 Mushrooms 88.1 3.5 0.4 6.8 1.2 185 Onions 10.0 78.9 1.4. 0.3 8.9 0.5 190 Parsnips 20.0 66.4 1.3. 0.4 10.8 1.1 230 Peas (Pisum sativum), dried. 9.5 24.6 1.0 62.0 2.9 1565 shelled 74.6 7.0 0.5 16.9 1.0 440 Cowpeas, dried 13.0 21.4. 1.4 60.8 3.4 1505 Potatoes 20.0 62.6 1.8. 0.1 14.7 0.8 295 Vegetables: Rhubarb 40.0 56.6 0.4 0.4 2.2 0.4 60 Sweet potatoes 20.0 55.2 1.4 0.6 21.9 0.9 440 Spinach 92.3 2.1 0.3 3.2 2.1 95 Squash 50.0 44.2 0.7 0.2 4.5 0.4 100 Tomatoes 94.3 0.9 0.4 3.9 0.5 100 Turnips 30.0 62.7 0.9 0.1 5.7 0.6 120 Vegetables, canned: Baked beans 68.9 6.9 2.5 19.6 2.1 555 Peas (Pisum sativum), green 85.3 3.6 0.2 9.8 1.1 235 Corn, green 76.1 2.8 1.2 19.0 0.9 430 Succotash 75.9 3.6 1.0 18.6 0.9 425 Tomatoes 94.0 1.2 0.2 4.0 0.6 95 Fruits, berries, etc., fresh: [E] Apples 25.0 63.3 0.3 0.3 10.8 0.3 190 Bananas 35.0 48.9 0.8 0.4 14.3 0.6 260 Grapes 25.0 58.0 1.0 1.2 14.4 0.4 295 Lemons 30.0 62.5 0.7 0.5 5.9 0.4 125 Muskmelons 50.0 44.8 0.3 4.6 0.3 80 Oranges 27.0 63.4 0.6 0.1 8.5 0.4 150 Pears 10.0 76.0 0.5 0.4 12.7 0.4 230 Persimmons, edible portion 66.1 0.8 0.7 31.5 0.9 550 Raspberries 85.8 1.0 12.6 0.6 220 Strawberries 5.0 85.9 0.9 0.6 7.0 0.6 150 Watermelons 59.4 37.5 0.2 0.1 2.7 0.1 50 Fruits, dried: Apples 28.1 1.6 2.2 66.1 2.0 1185 Apricots 29.4 4.7 1.0 62.5 2.4 1125 Dates 10.0 13.8 1.9 2.5 70.6 1.2 1275 Fruits, dried: Rhubarb 40.0 56.6 0.4 0.4 2.2 0.4 60 Figs 18.8 4.3 0.3 74.2 2.4 1280 Raisins 10.0 13.1 2.3 3.0 68.5 3.1 1265 Nuts: Almonds 45.0 2.7 11.5 30.2 9.5 1.1 1515 Brazil nuts 49.6 2.6 8.6 33.7 3.5 2.0 1485 Butternuts 86.4 0.6 3.8 8.3 0.5 0.4 385 Chestnuts, fresh 16.0 37.8 5.2 4.5 35.4 1.1 915 Chestnuts, dried 24.0 4.5 8.1 5.3 56.4 1.7 1385 Cocoanuts [F] 48.8 7.2 2.9 25.9 14.3 0.9 1295 Cocoanut, prepared 3.5 6.3 57.4 31.5 1.3 2865 Filberts 52.1 1.8 7.5 31.3 6.2 1.1 1430 Hickory nuts 62.2 1.4 5.8 25.5 4.3 0.8 1145 Pecans, polished 53.2 1.4 5.2 33.3 6.2 0.7 1465 Peanuts 24.5 6.9 19.5 29.1 18.5 1.5 1775 Pinon (Pinus edulis) 40.6 2.0 8.7 36.8 10.2 1.7 1730 Walnuts, black 74.1 0.6 7.2 14.6 3.0 0.5 730 Walnuts, English 58.1 1.0 6.9 26.6 6.8 0.6 1250 Miscellaneous: Chocolate 5.9 12.9 48.7 30.3 2.2 5625 Cocoa, powdered 4.6 21.6 28.9 37.7 7.2 2160 Cereal coffee, infusion (1 part boiled in 20 parts water)[G] 98.2 0.2 1.4 0.2 30 =============================================================================

[Footnote A: Refuse, oil.] [Footnote B: Refuse, shell.]

[Footnote C: Plain confectionery not containing nuts, fruit, or chocolate.]

[Footnote D: Such vegetables as potatoes, squash, beets, etc., have a certain amount of inedible material, skin, seeds, etc The amount varies with the method of preparing the vegetables, and cannot be accurately estimated The figures given for refuse of vegetables, fruits, etc., are assumed to represent approximately the amount of refuse in these foods as ordinarily prepared.]

[Footnote E: Fruits contain a certain proportion of inedible materials, as skin, seeds, etc., which are properly classed as refuse. In some fruits, as oranges and prunes, the amount rejected in eating is practically the same as refuse. In others, as apples and pears, more or less of the edible material is ordinarily rejected with the skin and seeds and other inedible portions. The edible material which is thus thrown away, and should properly be classed with the waste, is here classed with the refuse. The figures for refuse here given represent, as nearly as can be ascertained, the quantities ordinarily rejected.]

[Footnote F: Milk and shell.]

[Footnote G: The average of five analyses of cereal coffee grain is: Water 6.2, protein 13.3, fat 3.4, carbohydrates 72.6, and ash 4.5 per cent. Only a portion of the nutrients, however, enter into the infusion. The average in the table represents the available nutrients in the beverage. Infusions of genuine coffee and of tea like the above contain practically no nutrients.]



CHAPTER XVII

DIETARY STUDIES

244. Object of Dietary Studies.—The quantity of food which different families purchase varies between wide limits; a portion being lost mechanically in preparation and a still larger and more variable amount in the refuse and non-edible parts. If a record is made of all foods purchased and the waste and non-edible portions are deducted, the nutrients consumed by a family may be calculated by multiplying the weight of each food by the average composition. If such calculations be made, it will be found that in some families nearly a half pound per day of both protein and fat is consumed by adults, while in other families less than half of this amount is used. The object of dietary studies is to determine the source, cost, composition, and nutritive value of the foods consumed by different families; they also enable comparisons to be made of the amounts of nutrients purchased. Extensive dietary studies have been made by the United States Department of Agriculture, and the results have been published in various bulletins.[76]

245. Wide and Narrow Rations.—When the amount of carbohydrates in a ration is small in comparison with the protein, it is called a narrow ration, while a wide ration is one in which the carbohydrates are much in excess of the protein. When a ration contains 0.40 of a pound of protein, 0.40 of a pound of fat, and 1 pound of carbohydrates, it has a nutritive ratio of 1 to 4.8 and is a narrow ration. To calculate the nutritive ratio, the fat is multiplied by 2-1/4, the product added to the carbohydrates, and this sum divided by the protein. It is not possible to designate accurately the amount of protein and other nutrients that should be in the daily ration of all persons, because the needs of the body vary so with different individuals. Hard and fast rules governing the amounts of nutrients to be consumed cannot as yet be formulated, as our knowledge of the subject is too limited. It is known that both excessive and scant amounts are alike injurious. While the appetite may indicate either hunger or satiety, it alone cannot always be relied upon as a safe guide for determining the amount and kind of food to consume, although the demands of appetite should not be disregarded until it has been demonstrated beyond a doubt that it is not voicing the needs of nature. There has been a tendency which perhaps was a survival of the Puritanical ideas of the early days to stamp as hurtful whatever seemed desirable and pleasant; as examples might be cited the craving for water by fever patients, and for sugar by growing children, which have now been proven to be normal demands of nature.

246. Dietary Standards.—As a result of a large number of dietary studies and digestion experiments, dietary standards have been prepared. Atwater in this country and Voit in Germany have proposed such standards for men employed at different kinds of labor, as follows:

========================================================================== Protein Fat Carbo- Fuel Nutritive hydrates Value - - - - lb. lb. lb. Calories Ratio Man with little physical exercise 0.20 0.20 0.66 2450 5.5 Man with light muscular work 0.22 0.22 0.77 2800 5.7 Man with moderate muscular work 0.28 0.28 0.99 3520 5.8 Man with active muscular work 0.33 0.33 1.10 4060 5.6 Man with hard muscular work 0.39 0.55 1.43 5700 6.9 ==========================================================================

In the table it will be seen that the quantity of nutrients increases with the labor to be performed. In order to secure the necessary heat and energy, rations for men at heavy labor contain proportionally more fat and carbohydrates than are required for light work. All dietary standards, however, should be regarded as tentative only. Opinions differ greatly on different points; for example, as to the amount of protein a ration should contain. This is a matter that can be determined only from extended investigations under a variety of conditions, and as yet results are too meager to formulate other than tentative standards. Chittenden has found that the body can be sustained on very much less protein than is called for in the standard ration.[77] The amount of protein in the ration should be ample to sustain the body weight and maintain a nitrogen equilibrium; that is, the income and outgo of nitrogen from the body should be practically equal.



"While one freely admits that health and a large measure of muscular strength may be maintained upon a minimum supply of protein, yet I think that a dispassionate survey of mankind will show that races which adopt such a diet are lacking in what, for want of a better word, one can only describe as energy." [28]

On the other hand, excessive and unnecessarily large amounts of protein are sometimes consumed, adding greatly to the cost of the ration and necessitating additional labor on the part of the body for its elimination.

247. Number of Meals per Day.—Some persons advocate two meals per day rather than three, but dietary studies show that the best results are secured when the food is divided among three rather than two meals, and with a two-meal system the tendency is to consume a larger total amount of food than when three meals are eaten. It is not essential that the food be equally divided among the three meals. Any one of them may be lighter or more substantial as the habits and inclinations of the individual dictate. If it is found necessary to reduce the total quantity of food consumed, this may be done by a proportional reduction of each of the meals, or of any one of them instead of decreasing the number of meals per day. The occasional missing of a meal is sometimes beneficial, in cases of digestion disorders, but the ordinary requirements of persons in normal health who have either mental or physical labor to perform are best met when three meals per day are consumed, as this insures an even supply of nutrients. For persons of sedentary habits, the kind and quantity of food at each meal must be regulated largely by the individual from knowledge based on personal experience.

"In the matter of diet every man must, in the last resort, be a law unto himself; but he should draw up his dietetic code intelligently and apply it honestly, giving due heed to the warnings which nature is sure to address to him should he at any time transgress."[28]

If there is trouble in digesting the food, it is well to study the other habits of life along with the food question, for it may be the difficulty arises from some other cause, and would be remedied by more exercise and fresh air, avoiding rush immediately after meals, more thorough mastication, or less worry. It is a serious matter to shut off the supply of food from a person not suffering from some disease and who is working; as well cut off the supply of fuel from a furnace and then expect a full amount of energy and heat. But unlike the furnace, when the human body is deprived of needed nutrients it preys upon itself and uses up its reserve that should be drawn upon only in cases of illness or extreme nervous strain. Some persons live in such a way as to never have any reserve of strength and energy to call upon but use up each day all the body can produce and so become physical bankrupts when they should be in their prime. Food is required for the production of nerve energy as well as physical energy.[78]

248. Mixed Dietary Desirable.—Experiments in the feeding of farm animals show that the best results come from the combination of a number of foods to form a mixed ration, rather than from the use of one food alone,[79] for in this way the work of digestion is more evenly distributed, and a higher degree of efficiency is secured from the foods consumed. The same is true in human feeding; the best results are secured from a mixed diet. Ordinarily, about two fifths of the nutrients of a ration are derived from animal and three fifths from vegetable sources.

249. Animal and Vegetable Foods; Economy of Production.—Animal foods can never compete in cheapness of the nutrients with cereals and vegetables, as it takes six to eight pounds or more of a cereal, together with forage crops, to make a pound of meat. Hence the returns in food value are very much larger from the direct use of the cereals as human food, than from the feeding of cereals to cattle and the use of the meat. As the population of a country increases, and foods necessarily become more expensive, cereals are destined to replace animal foods to a great extent, solely as a matter of economy.

250. Food Habits.—Long-established dietary habits and customs are not easily changed, and when the body becomes accustomed to certain foods, substitution of others, although equally valuable, may fail to give satisfactory results. For example, immigrants from southern Europe demand foods with which they are familiar, as macaroni, olive oil, and certain kinds of cheese, foods which are generally imported and more expensive than the staples produced in this country,[80] and when they are compelled to live on other foods, even though they have as many nutrients, they complain of being underfed. Previously acquired food habits appear to affect materially the process of digestion and assimilation. Sudden and pronounced change in the feeding of farm animals is attended with unsatisfactory results, and whenever changes are made in the food of either humans or animals they should be gradual rather than radical.

251. Underfed Families.—As the purchasing of food is often done by inexperienced persons, palatability rather than nutritive value is made the basis of choice. Dietary studies show that because of lack of knowledge of the nutritive value of foods, whole families are often underfed. Particularly is this true where the means for purchasing foods are limited. In dietary studies among poor families in New York City,[81] the United States Department of Agriculture notes: "It is quite evident that what is needed among these families more than anything else is instruction in the way to make the little they have go the farthest." Some classes of the rich too are equally liable to be underfed, as they are more prone to food notions and are able to indulge them. Among the children of the rich are found some as poorly nourished as among the poor.

252. Cheap and Expensive Foods.—Among the more expensive items of a ration are meats, butter, and canned fruits. The difference in composition and nutritive value between various cuts of meat is small, being largely physical, and affecting taste and flavor rather than nutritive value. Expensive cuts of meat, high-priced breakfast cereals, tropical fruits and foods which impart special flavors, add little in the way of nutritive value to the ration, but greatly enhance the cost of living. Ordinarily the cheapest foods are corn meal, wheat flour and bread, milk, beans, cheese, sugar, and potatoes.[7] The amount of animal and vegetable foods to combine with these to form a balanced ration may be governed largely by personal preference or cost, as there is little difference in nutritive value. The selection of foods on the basis of cost and nutritive value is discussed in Chapter XVI.

253. Food Notions.—Many erroneous ideas exist as to the nutritive value of foods, and often wholesome and valuable foods are discriminated against because of prejudice. Skim milk is usually regarded as containing little if any nourishing material, when in reality it has a high protein content, and can be added to other foods to increase their nutritive value. The less expensive cuts of meat contain more total nutrients than many of the more expensive ones. Beef extracts have been erroneously said to contain more nutrients than beef,[51] and mushrooms to be equal in value of beefsteak; chemical analyses fail to confirm either statement. The banana also has been overestimated as to food value, and while it contains more nutrients than many fruits, it is not the equal of cereals, as has been claimed.[82] Cocoa, although a valuable beverage, adds but little in the way of nutrients to a ration unless it is made with milk. The value of a food should be based upon its composition as determined by chemical analysis, its digestibility as founded upon digestion experiments, and its palatability and mechanical structure. Food notions have, in many instances, been the cause of banishing from the dietary wholesome and nutritious foods, of greatly increasing the cost of living, as well as of promulgating incorrect ideas in regard to foods, so that individuals and in some cases entire families have suffered from improper or insufficient food.

254. Dietary of Two Families Compared.—A dietary study often reveals ways in which it is possible to improve the ration in kinds and amounts of food, and sometimes at less expense. The following dietaries of two families for the same period show that one family expends over twice as much in the purchase of foods as the other family, and yet the one whose food costs the less actually secures the larger amount of nutritive material and is better fed than the family where more money is expended for food.[13]

FOOD CONSUMED, ONE WEEK

FAMILY No. 1

20 loaves of bread $1.00 10 to 12 lb. loin steak, or meat of similar cost 2.00 20 to 25 lb. rib roast, or similar meat 4.40 4 lb. high-priced cereal breakfast food, 20 ct. 0.80 Cake and pastry purchased 3.00 8 lb. butter, 30 ct. 2.40 Tea, coffee, spices, etc 0.75 Mushrooms 0.75 Celery 1.00 Oranges 2.00 Potatoes 0.25 Miscellaneous canned goods 2.00 Milk 0.50 Miscellaneous foods 2.00 3 doz. eggs 0.60 ——— $23.45

FAMILY No. 2

15 lb. flour, bread home-made (skim milk used) $0.45 Yeast, shortening and skim milk 0.10 10 lb. steak (round. Hamburger and some loin) 1.50 10 lb. other meats, boiling pieces, rump roast, etc. 1.00 5 lb. cheese, 16 cents 0.80 5 lb. oatmeal (bulk) 0.15 5 lb. beans 0.25 Home-made cake and pastry 1.00 6 lb. butter, 30 ct. 1.80 3 lb. home-made shortening 0.25 Tea, coffee, and spices 0.40 Apples 0.50 Prunes 0.25 Potatoes 0.25 Milk 1.00 Miscellaneous foods 1.00 3 doz. eggs 0.60 ——— $11.30



In comparing the foods used by the two families, it will be observed that family No. 1 purchased their bread at the bakery at a cost of $ 1.00, while the bread of family No. 2 was home-made, skim milk being used in its preparation, the flour, milk, yeast, and shortening costing about 55 cents. Family No. 1 consumed 10 pounds of expensive steaks, family No. 2 consumed the same number of pounds, a portion being cheaper cuts. Instead of the 20 pounds of roast or similar beef used by family No. 1, only one half as much and cheaper cuts as boiling pieces, stew, rump roast, etc., were used by family No. 2; 5 pounds of beans and 5 pounds of cheese taking the place of some of the meat. Family No. 1 consumed 4 pounds of high-priced cereal breakfast foods, supposing they contained a larger amount of nutrients than were actually present. In place of the 4 pounds of high-priced cereal breakfast foods of family No. 1, family No. 2 used 5 pounds of oatmeal purchased in bulk. Family No. 1 bought their cake and pastry for $3.00, while those of family No. 2 were home made and cost $1.00. Family No. 2 used 2 pounds less butter per week because of the preparation and use of home-made shortening from beef suet and milk. They also purchased a smaller amount of tea, coffee, and spices than family No. 1. Family No. 2 consumed a larger quantity of less expensive fruits and vegetables than family No. 1, who ate 75 cents' worth of mushrooms with the idea that they contained as much protein as meat, but analyses show that mushrooms contain no more nutrients than potatoes and similar vegetables. In place of the celery and oranges, apples and prunes were used by family No. 2. The same amount of potatoes was used by each. Fifty cents was spent for milk by family No. 1 and $1.00 by family No. 2. The total amount expended for food by family No. 1 was $23.45, while family No. 2 purchased a greater variety of foods for $11.30, as well as foods containing more nutrients. The approximate amounts of nutrients in the foods purchased by the two families are given in the following table, from which it will be observed that family No. 2 obtained a much larger amount of total nutrients and was better fed at considerably less expense than family No. 1.

NUTRIENTS IN FOODS CONSUMED.—FAMILY NO. 1

============================================= PROTEIN FAT CARBOHYDRATES LB. LB. LB. - - - 20 lb. bread 1.98 0.28 11.42 10 lb. loin steak 1.59 1.76 20 lb. rib roast 2.68 4.26 4 lb. cereals 0.42 0.06 2.75 8 lb. butter 0.04 6.80 25 lb. potatoes 0.45 0.03 3.83 20 lb. milk 0.70 0.80 1.00 - - - 7.86 13.99 19.00 =============================================

FAMILY NO. 2 ===================================================== PROTEIN FAT CARBOHYDRATES LB. LB. LB. - - - - 15 lb. flour 1.89 0.12 11.15 5 lb. skim milk 0.16 0.01 0.26 10 lb. round steak 1.81 1.26 10 lb. beef 1.32 2.02 5 lb. cheese 1.40 1.75 5 lb. oatmeal 0.78 0.36 3.40 6 lb. butter 0.03 5.10 3 lb. shortening 2.55 3 lb. prunes 0.03 0.60 25 lb. apples 0.12 2.50 25 lb. potatoes 0.45 0.03 3.83 40 lb. milk 1.44 1.60 1.90 5 lb. beans 1.12 3.00 - - - 10.55 14.80 26.64 - - - Difference in nutrients in favor of family No. 2, consuming the cheaper 2.69 0.81 7.64 combination of foods =====================================================

255. Food in its Relation to Mental and Physical Vigor.—When the body is not properly supplied with food, the best results in the form of productive work cannot be secured. There is a close relationship between the nature of the food consumed and mental activity, also ability to satisfactorily perform physical labor. "The productive power of the individual as well as of the nation depends doubtless upon many factors other than food, such as race, climate, habit, etc., but there is no gainsaying the fact that diet has also a profound and direct influence upon it."[83]

If the body is diseased, it cannot make the right uses of the food, and often the food is blamed when the trouble is due primarily to other causes. The fact that a diseased digestive tract is unable to utilize some foods is no valid reason why these foods should be discarded in the dietary of persons in normal health, particularly when the food is in no way responsible for the disease.

Some diseases are most prevalent in the case of a restricted diet. A change in the dietary of the Japanese navy greatly improved the health of the sailors.

"The prevalence of kakke or beriberi in the navy turned the attention of many medical specialists toward the problem of nutrition.... It was generally believed that there was some very close connection between the disease and the rice diet.... One outcome of these investigations was the passage of the food supply act of the navy in 1884. The ration provided in accordance with this act was sufficient to furnish an abundance of protein and energy.... Following the change of ration in 1884, the prevalence of the disease was very materially diminished, and at the end of three years cases of kakke were practically unknown among the marines."[83]

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