Fats Of Animal Origin
( Originally Published 1913 )
All foods, before they are absorbed by the intestines, must first be brought into a fluid condition. This rule holds good for the fats, and it is for this reason that such fats as are not soluble and do not melt at the temperature of our bodies are digested with difficulty. Lamb-fat melts at a temperature of 450 to 55 ° C.; it is therefore very indigestible. Next in order in respect of digestibility comes beef-fat; its melting point is lower than that of lamb-fat, yet often exceeds 40° C. Pork-fat is rather better, but it also melts at about 40° C., and frequently even at a higher temperature. The Jews are wise in cooking with goose-fat, which has its melting point always below 40° C.; on the average it is 30° to 350 C., but sometimes it is lower than that. Goose-fat is consequently the most easily digested fat, because its melting point is the lowest of any fat of animal origin. Its taste is pleasant, and it is more healthful than pork-fat. Butter made from cows' milk is also very wholesome, and, next to goose-fat, probably melts at a lower temperature than any other. For this reason it is quite justifiable to employ butter for daily use in preparing food. It is certainly not healthful to use beef-fat (drippings) for cooking, as is done in many hotels in England. I have learned from personal experience how frequently one has eructations and acid is formed in the stomach after its use. That lamb-fat remains for a considerable time in the stomach can often be noticed after one has eaten fat lamb for dinner. Fat, in general, retards the movements of the stomach.
Fluid fat, such as fish-blubber and codliver oil, is not very indigestible, and both children and adults can tolerate quite a considerable amount of the finer varieties, although it has a much more unpleasant taste than other animal fats. It is certainly worthy of being much more generally used by weak, delicate adults, and by persons who have been debilitated by exhausting diseases, than it is now, as it is well absorbed and assimilated. Animal fats in general are well assimilated, as has been shown in the case of milk-fats by the experiments of Tschernoff. Among the Eskimos, fish-blubber forms a large part of the diet; in common with other northern peoples, they have a great predilection for fats. In Scandinavia butter is never absent from the table, especially in Sweden, where at every meal it is thickly spread upon the Swedish graham bread —"Knâkebrôd"—or upon white bread.
This preference on the part of dwellers in cold climates for fats is probably due to the necessity of a food rich in calories, i.e., which will produce much heat; and fat, of all foods, is that of greatest value in this direction. Even in temperate climates the daily addition of a considerable amount of fat to the diet increases the nutritive value of the latter and improves the taste of the viands. Butter is best for this purpose, as has already been said; indeed, our food in general should be prepared with it; to vegetables, in particular, it should be freely added. Butter is far better than vegetable fats, as I have ascertained from personal experience.
Fatty foods should be ingested by persons desirous of rapidly taking on flesh, since the fat absorbed from foods, if well digested and assimilated, will speedily produce this result. Too much fat, however, should not be taken at one time, as the assimilation of other foods will stiffer. That fat should be avoided by the obese is self-evident; diabetics, on the other hand, by taking fats with vegetables may derive some benefit from their use. The butter which they use should, however, be well washed out and freed of fatty acids, as otherwise rapid formation of the dreaded acetone bodies may follow. Pigs' lard and certain vegetable fats containing the least amount of fatty acids, e.g., cottonseed oil (which, according to, Salkowski, contains only o.29 per cent.), would be preferable in such cases.
LEGUMINOUS VEGETABLES AND THEIR IMPORTANCE
When it is desired to absorb a large amount of vegetable albumin, it is best to rely especially on the leguminous varieties. These are so rich in albumin as to be unsurpassed in this respect by any other vegetable or even animal food. The difference between the albumin contained in animal tissues and that of leguminous vegetable foods lies in the fact that meat albumin is well assimilated, whereas this is not the case with that contained in legumes, when prepared in the usual way, even if they have been cooked for a considerable time. When used in the form of a purée they are more digestible and are better assimilated, so that no great amount is passed out unused by the intestine.
The special property which renders leguminous vegetables hard to digest and to assimilate is the quantity of cellulose or woody fiber contained in them, which greatly exceeds that present in the majority of other foods. This tough, horny substance prevents the action of the intestinal fluids upon the food, and thus there is lost not only a portion of the albumin, but also of the carbohydrate material,—although not so much of the latter as of the albumin. The carbohydrate content of leguminous vegetables is quite considerable, and in some, as in the soy bean, to which we shall refer at greater length in an appendix to this chapter, there is also a large proportion of fat. In order that these nutritive elements of the leguminous vegetables should be assimilated as completely as possible, the method of preparation and cooking is, however, of great importance. In the first place they must be cooked in soft water, since their albumin, which, owing to its great similarity to casein, has been called vegetable casein or legumin, forms together with the lime, when cooked in hard water, as stated by P. F. Richter, an insoluble combination which is but poorly assimilated. By the addition of a little bicarbonate of sodium to the water, this, however, can be avoided. According to P. F. Richter, 10.16 per cent. of the nitrogen and 19 per cent. of the nutrient salts are not assimilated from peas which have been boiled in soft water; from those cooked in hard water the nitrogen loss amounts to 16.60 per cent. and that of the nutrient salts to 42.22 per cent.
The most advantageous mode of preparing leguminous vegetables is in the form of a purée, as by this method the greater part of the cellulose which interferes with digestion and assimilation is removed. The high albumin content of these vegetables is best utilized if, after the husks have been removed, the rest is ground to a fine powder and then mixed with some other flour less rich in albumin, e.g., rye flour. From this a bread is made which is much richer in albumin than that made from ordinary flour, and which well deserves the name of "Kraftbrot" (strength bread). The most nutritive of these breads is undoubtedly the soy bread, on account of the higher percentage of fat and, especially, the exceptionally large amount of albumin it contains.
After the foregoing introductory remarks concerning the value of leguminous vegetables, we shall now present an analysis of the varieties most used when in a ripe, full-grown condition; fresh, green vegetables will be further referred to. in a succeeding chapter. In addition to the percentages of the various nutritive elements, which we quote from König, we shall also indicate what proportion of these substances is assimilated.
In addition to this exceedingly rich and valuable nutritive content of the leguminous vegetables, there are also present in them quite considerable amounts of important nutritive salts-above all, a great deal of potash and phosphorus, and, in comparison with other vegetables, also much lime. Of the latter they contain more than the cereals and many other vegetable products.
We find in the above a pretty high content of phosphorus although the cereals contain more of it-and of phosphoric acid, which manifests itself in the acid condition of the urine; the leguminous vegetables therefore share this property with meat; this applies also to their considerable nitrogen content.
The sulphur contained in certain leguminous vegetables, such as beans, is responsible for the flatulency caused by them. It is also important to note that these vegetables contain much lecithin—i per cent. As far as the digestibility is concerned, we see from the above table that the albumin contained in peas is best assimilated. This is due to the fact that peas are eaten without their shells. Green peas are best digested and assimilated, as we shall show elsewhere. They are also most frequently used, for when peas are quite ripe and old they are very hard to digest and assimilate, but are nevertheless better in this respect than beans or lentils under similar conditions. According to Rubner, when large quantities of peas are eaten, 14.5 per cent. of the dry substance, 27.8 per cent. of the nitrogen, 75 per cent, of the fat, 6.9 per cent. of carbohydrate, and the large amount of 3.5 per cent. of the nutrient salts are eliminated unused. Peas are much better assimilated when taken in small quantities, when only 17.5 per cent. of the nitrogen is lost. The best assimilation takes place when peas are eaten in the form of a purée; in this way they are assimilated about as are fine wheat flour and macaroni.
We have already mentioned that leguminous vegetables contain considerable lecithin—more than the cereals. Peas contain 1.05 per cent. ; other substances found in peas, namely, the purin bases, have, however, an injurious action, since they increase the formation of uric acid. According to, Walter Hall and the latest experiments of Bessau and Schmidt, they contain quite considerable amounts of these substances, but, nevertheless, not so much as do lentils; peas contain o.018 gram in 100 grams, while the lentils, which, among the legumes, have the greatest quantity of purin, contain 5 cg. in 100 grams.
The best way to eat full-grown peas is in a purée, and they are usually prepared in this manner. In some countries, as in Spain, for instance, large dried peas, of a variety common in that country, are a universal and greatly liked food, and these "Garbanzos" form, as I have seen, a daily addition to the diet, both there and in Mexico. They may, in a measure, be responsible for the obesity which so frequently affects, the women of these countries. The purée form is decidedly preferable, but it has the disadvantage of being merely swallowed, with but little, if any, mastication. With such a purée some-thing hard should be eaten, as, for instance, a piece of rye bread; in this way it would require mastication and would then be better digested.
Purée of peas is rendered very nourishing when bacon or sausage is taken with it. This food is often given to the German soldier, who thus receives a truly nourishing diet, containing all three of the main groups of our foods, and for a soldiers' stomach it is not very hard to digest. Some people declare that the German army has accomplished its able work not only because of the efficient German instructors, but also because of the "Erbstwurst" (pea sausage), and it is certainly true that a sufficiently rich and complete food, such as this sausage, plays an important rôle—in reality much more important than is generally believed—in making an army capable of marching and of successful action. In pea sausage there is not very much meat, but the carbohydrates, vegetable albumin, and fat are all well represented.
Lentils are also a valuable food. Since, however, according to Strümpel, they are but poorly assimilated after having been soaked and then cooked,—nearly 40 per cent., thus pretty nearly the half, of the albumin content being lost,—they, too', are best taken in the form of purée. They are then well assimilated, as was found by Strümpel, and only 9 per cent. is lost. I also observed that when boiled lentils were eaten in considerable quantities the undigested skins were present in the stools.
That which makes lentils so nourishing is the rather large proportion of iron contained in them, particularly in the Egyptian lentils, which are the best variety. It is not only among leguminous vegetables, but among other foods as well, that lentils occupy a first position in regard to the iron content. When finely ground, they form a most valuable food, the "Revalenta arabica," which, as stated by Hutchison, contains 22 per cent. of easily digested and assimilated albumin, 1.5 per cent. of fat, and 65.2 per cent. of carbohydrates. Owing to their limited sulphur content, lentils cause but little flatulence, and in the form of purée are really a food deserving of much more attention than is at present accorded to it. That lentils are so neglected as never to be included in the bill of fare in the best restaurants, notwithstanding their agreeable taste, is one of the incomprehensible anomalies too often met with in the present-day scheme of nourishment.
Another leguminous vegetable, the bean, almost as healthful as the lentil, is, on the contrary, very much used. Probably in no country in the world are beans more used than in the United States, as in the form of "Boston baked beans." One finds them in all the restaurants and buffet cars in the Union cooked with bacon, as "pork and beans." The experiments of Praussnitz show that the ripe white beans are poorly assimilated, even more so than other legumes, and this not only as regards the albumin, but the carbohydrates as well, of which 17.5 per cent. are unused. Beans, too, are better digested in the purée form. A thick bean purée soup tastes very good and is easily digested. Whole beans as well as lentils often pass through the intestinal canal undigested (Praussnitz). Beans as an article of diet have the great disadvantage of causing decided flatulency; there is hardly any other food either among the legumes or other varieties of food which causes this to such a marked degree. It is probably due to the large amount of cellulose and of sulphur contained in them. In fact, the disadvantage of inducing flatulency to a greater or less degree is common to all leguminous vegetables, and they have the additional drawback of causing acid eructations, to a much greater extent than many other foods, in persons who are predisposed to this condition; this is especially the case in nervous affections. Since they impose more work upon both the stomach and intestines, also causing more flatulency, than the majority of foods, leguminous vegetables should be strictly forbidden in stomach and intestinal diseases as well as in arteriosclerosis. Neither should they be allowed for persons suffering from gout, since they contain a considerable amount of purin bases, which favor the formation of uric acid; lentils contain the most, peas come next, and lastly beans. Persons who fear to grow stout should eat but little of the leguminous vegetables, and the same may be said of diabetics. For the latter it is best, according to my experiments lately cited, to eat these leguminous vegetables whole, that is to say, with their skins, since they are not so well assimilated in this way, and consequently do not greatly increase the sugar secretion in mild cases of diabetes. These vegetables should form the principal portion of a vegetarian diet, as they alone contain albumin, that important nutrient, in appreciable quantities. For healthy persons the leguminous vegetables form the best vegetable diet.